JBL 43xx Charged Coupled Network Boards

[VinylGroove]

I've been wanting to do this to my 4343's for a long time now and wondered why no one has offered something like these boards that just showed up in my ebay feed. Does anyone here have experience with these specific boards/networks, or with Echo Mountain Audio? Ebay listing:https://www.ebay.com/itm/325442735517Slightly Website:https://echomountainaudio.com/collections/jbl-4300-serieshttps://i.ebayimg.com/images/g/IfoAAOSwmjVjhR4s/s-l1600.jpghttps://i.ebayimg.com/images/g/f40AAOSwGcBjhR41/s-l1600.jpghttps://i.ebayimg.com/images/g/LFIAAOSwFpxjhR6v/s-l1600.jpghttps://i.ebayimg.com/images/g/wI0AAOSwV2hjhR60/s-l1600.jpg

[Robh3606]

Not all parts are the same size. Some may fit others may not.

There is an attached appendix that lists the parts used for the layout.

If you choose to use other parts verify the sizes.

From their site.

Rob :)

[VinylGroove]

What specific parts are they laid out for. Not all parts are the same size. Some may fit others may not. Rob :) EDIT: You updated your reply and beat me to mentioning the Appendix with parts. I would definitely follow it verbatim. Seems to be very well thought out. Example sent of a completed board that was built for use externally in it's own box, which is what I'd like to do. https://i.imgur.com/dwBOnyT.png

[VinylGroove]

I think I'm going to go for it. I noticed in the appendix it specifies different components for different 43xx models.For my 4343's would I want to do the 4344/45 spec instead of 4343 spec if I'm using all original 4343 drivers?

[speakerdave]

I think I'm going to go for it. I noticed in the appendix it specifies different components for different 43xx models.For my 4343's would I want to do the 4344/45 spec instead of 4343 spec if I'm using all original 4343 drivers?I infer from your question that you wonder if the 4344-45 crossover is an improvement of a general crossover for the four-way 43xx monitors—like a 43xx crossover 2.0.No, it isn't. The crossovers derive from the task of making a given set of drivers work well together, so using the original set for the 4343 you would follow that crossover schematic.

[VinylGroove]

I infer from your question that you wonder if the 4344-45 crossover is an improvement of a general crossover for the four-way 43xx monitors—like a 43xx crossover 2.0.No, it isn't. The crossovers derive from the task of making a given set of drivers work well together, so using the original set for the 4343 you would follow that crossover schematic.Thanks, I went ahead and bought the boards and all components are on their way for 4343 spec. If anyone is curious, the Solen caps & inductors, Mills resistors, etc. were about $1500 shipped.

[Ian Mackenzie]

Are you building the crossover in or outside the enclosure?

Given the presentation of those pcbs l personal would put a clear perspex sheet on top of an external crossover housing and show it off to your friends.

[mattking52]

I think I'm going to go for it. I noticed in the appendix it specifies different components for different 43xx models.For my 4343's would I want to do the 4344/45 spec instead of 4343 spec if I'm using all original 4343 drivers?Thanks for your interest in the boards! You definitely did the right thing by following the 4343 column of the parts list instead of the 4344/4345 configuration. By using the parts listed in the 4343 column, you'll have a charge-coupled crossover with voltage drives equivalent to the stock 3143 network. If you ever did update your drivers to 4344 specs, you could then modify the crossover components accordingly.
Are you building the crossover in or outside the enclosure?Given the presentation of those pcbs l personal would put a clear perspex sheet on top of an external crossover housing and show it off to your friends.Ian, this is exactly what I plan to do with my own, eventually (mine are still in the silly little MDF "test sled" configuration that Vinyl_Groove showed in the image below, with my early version of the boards that I just made for myself). In the meantime, fellow Lansing Heritage user Ricpan has done exactly this with the enclosures that he's built around our crossover PCBs. Adding a link to his post on another JBL-related group since image uploads don't see to be working (hope that's okay): https://www.facebook.com/groups/JBLALTEC/permalink/2131826193668636/

[VinylGroove]

Yes, I'm definitely building/buying a box to house the crossovers in. Super excited for this. Here are images from that FB post. I can't seem to post attachments either, but can link them using img tags. https://scontent.fslc3-2.fna.fbcdn.net/v/t39.30808-6/315485045_5811123898955541_8556729082105032758_n.j pg?_nc_cat=111&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=s0Nqtt7oylAAX-da6M5&_nc_ht=scontent.fslc3-2.fna&oh=00_AfBHpOkbF8O2tH6vehMIViJq0U7Yhq8PXgh7_txhV5Wt Mg&oe=638AF0EBhttps://scontent.fslc3-1.fna.fbcdn.net/v/t39.30808-6/315120128_5811124525622145_5246266194617021453_n.j pg?_nc_cat=103&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=YEsidiREe7wAX9ngXPW&_nc_ht=scontent.fslc3-1.fna&oh=00_AfDTpTT0tnJk-cZhTWsZQ82DZIaNvxMOweKkXHws_4U4tg&oe=638AD983https://scontent.fslc3-1.fna.fbcdn.net/v/t39.30808-6/315524682_5811124662288798_2249308109351010847_n.j pg?_nc_cat=102&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=oXZvFPLF5UoAX_SIQfX&_nc_oc=AQnlM5O-oEF92yZArhRGnVqs9-3ZhtxjbpogDnxgQwSDjRCVgM8D3aKhJ3B4sRMiowo&_nc_ht=scontent.fslc3-1.fna&oh=00_AfCwMqSWdAciauBdzYyIRR8nr0niu-QLyy2NXDomappepA&oe=638B424Fhttps://scontent.fslc3-1.fna.fbcdn.net/v/t39.30808-6/314975637_5811124715622126_6909200824967928129_n.j pg?_nc_cat=102&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=WSnugZqzFw0AX-lyh_7&_nc_ht=scontent.fslc3-1.fna&oh=00_AfDnihHlTPs842Nwu74IW8Mm8YjF9M8B42IxpVY7d8kT uQ&oe=638AAC46

[mattking52]

Weird - I tried using the img tags, and the images didn't show up, but glad it worked for you!

[mattking52]

Not all parts are the same size. Some may fit others may not. There is an attached appendix that lists the parts used for the layout. If you choose to use other parts verify the sizes.From their site.Rob :)Good advice, Rob, and thanks for checking out the user manual. Most reasonably sized polypropylene caps should fit -- you can see some purple ClarityCaps in the pics below that were used by Ricpan in place of the stock Solens (just because he had them on hand) -- but as you said, definitely check the sizes before purchasing anything alternative to what's shown in the included parts list!

In lieu of the attachment in your post, here's a link to where the user manual lives, so that one can always access the latest version: https://echomountainaudio.com/pages/downloads

By the way, boards for the 4425, 4430, and 4435 are currently in the works...

[mattking52]

Yes, I'm definitely building/buying a box to house the crossovers in. Super excited for this.]

Let us know when you do! I'm really curious and excited to see all the creative ways these are going to get integrated into various systems.

[Ricpan]

I might add these boards are solid and more then support the weight of the components. It an easy build. I wish I had them when I built my first set of cc crossovers. The instructions and documentation make it easy even for a hack like me. I don't have a horse in the race just a happy camper.

[VinylGroove]

I might add these boards are solid and more then support the weight of the components. It an easy build. I wish I had them when I built my first set of cc crossovers. The instructions and documentation make it easy even for a hack like me. I don't have a horse in the race just a happy camper.That's great to hear. I'm good at following instructions but not as good at testing a completed electronic project or diagnosing issues, so I'll follow very closely and hope for the best when it's done.

[mattking52]

That's great to hear. I'm good at following instructions but not as good at testing a completed electronic project or diagnosing issues, so I'll follow very closely and hope for the best when it's done.Always feel free to contact me via email (email address listed in the user manual) or through the contact page on the site, and I'll be happy to provide any guidance you need.

[VinylGroove]

Always feel free to contact me via email (email address listed in the user manual) or through the contact page on the site, and I'll be happy to provide any guidance you need.

I bought both boards so I could have the choice to bi-amp or just use 1 amp as I'm doing right now at home. Is there a way to switch back and forth between bi-amp and single amp connection with these?


For those who have JBL 43xx's do you think biamp is worth the hassle?


Right now I'm running a Parasound A21 amp which is a high bias Class A/AB and probably staying class A with these highly efficient 4343's at my listening levels.

[Chas]

Quote: “For those who have JBL 43xx's do you think biamp is worth the hassle?“ Speaking as a longtime OEM 4345 owner, don’t waste any time getting them biamped. Massive improvement, IMHO.

[christo]

For those who have JBL 43xx's do you think biamp is worth the hassle?

The first upgrade you’ll want to do with a 43xx monitor is to bi-amp and once done - you’ll never go back.
Beside the cost of components for the LF circuit can be up to 50% to 65% the cost of a good electronic cross-over. So why pay for something that in the end will may obsolete (i.e. unused). I’ve built three 43xx series crossovers and never built the LF circuit.

[Ian Mackenzie]

I bought both boards so I could have the choice to bi-amp or just use 1 amp as I'm doing right now at home. Is there a way to switch back and forth between bi-amp and single amp connection with these?

For those who have JBL 43xx's do you think biamp is worth the hassle?

Right now I'm running a Parasound A21 amp which is a high bias Class A/AB and probably staying class A with these highly efficient 4343's at my listening levels.

The Parasound A21 is a very good amp. I use Parasound.

Question 1 answer :
What l would say is “ultimately” yes it is. But that’s not where you are at right now.


My recommendation :
Build the full passive crossover and enjoy it before embarking on any other changes. You will notice improvements in the transparency and transient performance and the bass will be better without the bi amp switch in the circuit.


Benefits of Bi amp mode :
Improved damping of the woofer and an increase in the overall dynamic range of your system beyond the use of a single stereo power amplifier. Bass notes are rendered with improved definition generally. If you play your system at high levels you may notice improved dynamic headroom before clipping of the power amps.

Bi amp mode removes the passive crossover on the woofer in the 3143 network. Those networks used iron core inductors which didn’t have a low dcr resistance. Typically 0.5 ohms. The bi amp switch in the 3143 network added around 0.5 ohms of dc resistance across the wipers on the signal and ground side of the multipole switch. The bi amp switch was a marketing idea and spoilt the performance of these systems. The switch causes a loss in transient detail due to the voltage drop across the switch wipers are high currents.


Alternatives to bi amp mode - A diy project :
Upgrading the inductor in the 3143 woofer filter with a low dcr resistance of 0.2 ohms or less (ERSE Super Q type), thick copper loudspeaker cables and high quality spades / terminals may improve the performance of the passive network. This is an expensive route to implement but may prove a good compromise if you prefer not to accept the added complexity of bi amping. I recommend you bypass the bi amp switch completely/ or build a new passive network. The Mylar capacitors used in those legacy networks muffled the performance of these stock systems.


Important considerings for bi amp mode :
As far as bi amp mode goes you keep all the above improvements of the charge-coupled network if you can acquire a premium active crossover. Very transparent active crossovers are rare and expensive. Otherwise you will loose out on what your charge-coupled passive crossover and your nice Parasound amp are giving you. In this type of situation is like everything in “audio”.

You won’t miss what you don’t have until you experience the moment of truth. Then there is no going back. But try telling that to the hoards. They will call you out for heresy.


Testing of a active crossovers :
I have mentioned the following on numerous occasions over the years.

Back in 2007 l built a high end active crossover which was tested in Porschedman system using Pass labs amps. It was a clone of the Pass Labs XVR1. At the time Ed confirmed that putting the prior active crossover he was using in the signal path did in fact detract from the fidelity of his system. If you do a search and you find those posts it’s there in black and white.

Question 2 answer :
Switching back and forth from bi amp to full passive mode is not necessarily straight forward.

The high amp used in bi amp mode is connected to the rear internal terminals of the 4343. These terminals are used for the full range amplifier in passive mode. You would need to select internal mode on the loudspeaker bi amp switch. Then reconnect the high power amp directly to your preamplifier so it functions as a full range amplifier.

What l recommend is that you listen carefully to several familiar tunes and then change to bi amp mode and play the same tunes again after adjusting the levels of all the drivers so they are identical to the passive levels ( using a measurement mic).


Edit: Added information.
I have putting everything relating to the topic of bi amping in a single post to avoid a fragmented back and forth posts making the thread very difficult to follow. For this reason DO NOT quote and edit this post. Just as questions referring to this post.

Not everyone viewing this post will accept or agree with what l have stated. The above comparison test was done systematically and under controlled conditions. It wasn’t placebo or confirmation bias that lead to the findings.

Those viewing this post who are or aren’t bi amping their 43XX don’t have to accept or agree with what l have stated in accordance with Forum Rules.

It’s the choice of each individual to determine for a variety of reasons which brand / grade of equipment they use with their own systems. As an individual you are entitled to believe and voice what you believe or your opinions as long as no one gets hurt in the exchange.

Copyright 2022 lan Mackenzie Audio

[Ian Mackenzie]

Here is a link to a 4343 system used a Jazz bar in Tokyo l visited in 2008.

If you scroll through the pages there are two Aleph 2 class A SE mono blocks running these 4343s. It was an impressive system as l recall.


https://www.instagram.com/p/B2bFhM4FEQ3/?igshid=MDJmNzVkMjY=

If anyone with a stock 4343 is interested l have a pair 2121 mid cone refoam kits.

[VinylGroove]

Here is a link to a 4343 system used a Jazz bar in Tokyo l visited in 2008.
If you scroll through the pages there are two Aleph 2 class A SE mono blocks running these 4343s. It was an impressive system as l recall.
https://www.instagram.com/p/B2bFhM4FEQ3/?igshid=MDJmNzVkMjY=
If anyone with a stock 4343 is interested l have a pair 2121 mid cone refoam kits.


Thanks for the response and all of the detail on biamping. I was making a lot of assumptions that were incorrect. I had no idea I would need an active crossover, I thought if I had an active crossover it would replace my entire internal network of the speaker, not work in unison with it.

Since I bought all of the components for full passive crossovers and have both boards, I think I will build them out and enjoy that for a while. Though I will keep my eye out for a deal on another Parasound amp and a good active crossover. (I'll do some searching here for recommendations, unless you have any?)

---

It's interesting you mention that Jazz bar in Tokyo. The first 4343's I ever heard were in this "Salon Bar" in Tokyo and it was then I decided I would end up with a pair. Their setup was done by Kenrick Sound and as far as I know, they were running it off of the single Triode TRV-845SE amp on the counter (20W class A), but they could have been biamping and had another amp under the counter, I don't know. They controlled music via a tablet and were extremely kind people who ran the place. (I don't drink alcohol so they made me a ginger ale with real ginger, 100% from scratch and it was incredible)

https://www.youtube.com/watch?v=-O8N0cJJhiY&ab_channel=KenrickSound--%E3%82%B1%E3%83%B3%E3%83%AA%E3%83%83%E3%82%AF%E3%8 2%B5%E3%82%A6%E3%83%B3%E3%83%89

http://norainu.crayonsite.info/

https://goo.gl/maps/AyxrAkkT7t9SZnHX9

[mattking52]

Replying a little late here, so this response will be somewhat multi-faceted...

I agree with all of the sentiments in the last few posts about bi-amping. It really does make a huge difference (my 4344s with our charge coupled crossover boards are biamped as well), but obviously the quality of the electronic crossover does play a huge part in how well it all pans out. I personally use a First Watt B4 (Nelson Pass design), with a 12dB/oct Linkwitz-Riley filter arrangement and crossover frequency of about 315 Hz, and it sounds great. I've tried another non-standard arrangements, frequency spreading (a la Douglas Self), etc., and always ended up coming back to the symmetrical LR12 arrangement. There are lots of threads on this forum about crossover choice... the Pass Labs XVR1 --pricier than the B4, but more adjustable in terms of filter Q-- is a great option (and has been used by Greg Timbers from JBL in the past). People seem to have had good experiences with the Bryston 10B as well, but I don't have any direct experience with those.

As Chas said, it would certainly be a very valid approach to save the money from the passive woofer/mid filters (i.e., the stuff on the "Aux board" in the case of your Echo Mountain boards) and go straight into an active crossover setup with just the Main boards. However, I can confirm that going through the process in steps is really rewarding, as Ian pointed out. FWIW, my own progression with the 4344s (which were in their stock factory configuration when I bought them) was:
1. Full passive mode (stock crossovers) with a Music Reference RM-10 mk2 Class A tube amp
2. Same configuration, but removing the bi-amp selector switch (noted as one of the very weak points of the design) and hardwiring it - huge step up right there in terms of bass performance and control
3. Stock crossover hard-wired into bi-amp mode, with the First Watt B4, the RM-10 mk2 driving the upper range, and a 130W solid state amplifier driving the woofer. Another huge leap, particularly in the midrange performance and bass clarity
4. Same bi-amp configuration, but with the stock crossover replaced with the Echo Mountain charge-coupled crossover boards. Again, a big leap forward, mostly heard in the upper octaves of the audio band. Greg Timbers knew what he was doing with this charge-coupled/biased capacitor approach!

Following a similar path to the above may be more expensive in the long run, and take more time, but again, it is quite rewarding, and you'll be able to subjectively link the audible improvements in performance with the modifications.

VinylGroove - regarding your question on being able to switch back and forth with your boards: yes, you can; it will just require removal/replacement of a couple of connections, highlighted in Figure 5 of the user manual. We can surely talk more about it once you get things built. Figures 3 and 5 are block diagrams of the bi-amp and full passive configurations, respectively, including the active crossover.

[Ian Mackenzie]

Hi Vinylgroo,

Over on Diyaudio.com there is an active crossover kit. If you are diy oriented with electronics assembly this kit may be of interest to you.

https://diyaudiostore.com/products/diy-biamp-6-24-crossover?variant=31765939322953

[Ian Mackenzie]

This is where it all started.

Whether your already a charge coupled crossover user or just lurking there is some interesting information in these threads.

https://www.audioheritage.org/vbulletin/showthread.php?8111-Charge-Coupling-on-the-Cheap&

https://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade

https://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade&p=127646&viewfull=1#post127646

[Ian Mackenzie]

EEK

I hadn’t realised it until l looked at the foreign exchange rate this morning but if you are planning to buy set of these next nice boards on a credit card or PayPal the AUD cost is $499.00 dollars for a full set of cards or $418.00 plus bank fees for a bi amp set. Just something to consider before you pull the trigger! Perhaps Echo Mountainaudio can look at prices for effected foreign markets.

[VinylGroove]

EEK

I hadn’t realised it until l looked at the foreign exchange rate this morning but if you are planning to buya set of these next nice boards on a credit card or PayPal the AUD cost is $499.00 dollars for a full set of cards and $418.00 plus bank fees for a bi amp set. Just something to consider before you pull the trigger! Perhaps Echo Mountainaudio can look at prices for effected foreign markets.

I know right now even though the dollar is comparatively strong, our costs here have skyrocketed on everything. Manufacturing costs are up at least 30% in many areas here in the US. Raw materials, labor, shipping etc are all a problem.

I finally have my components all ordered and have a good bit of sticker shock on those.

[Ian Mackenzie]

To respond to your post please find below the US inflation over 2022. Inflation has come down since June and was the same in Nov 2022 as Nov 2021.

I’m not asking you to advocate the pricing on the basis that you have purchased these nice pcbs.

My purpose here is is to make people aware that they need to investigate the real cost of building these charge coupled networks before they go ahead with buying these pcbs. The foreign exchange rate is an important consideration in determining the overall cost of such a diy project.

EBay is a market with global reach. It looks like a good idea at the time as often it is on Ebay and you go ahead. However, this isn’t a full crossover kit. There’s a parts list on the website. The buyer needs to go online and order all the parts which can take a while and they won’t know the cost until they go to the check out. They would do that once the boards arrive.

I very much doubt the average diy person really knows the overall cost of these crossovers until it’s finished! The cost of the parts, the pcb and hardware such as connectors and everything else really adds.

I know this because l assisted numerous people remotely all over the world get these complicated four way networks together. Once they got to the shop checkout online at Parts Express or wherever they plan to buy the parts from they came back to me via email looking for alternatives.

That is where l am coming from.

You’ve come on the forums looking for help which is great and you now realise just how expensive it is.

If people are looking at this thread and are interested in these boards it’s about doing the right thing and letting people know just what this whole thing all about. It’s not like it’s coupled hundred dollars. Its a real lot money.

I have an acquaintance here locally who has asked me if l would help assemble those boards and l said well you had better go online and look at what this is going to cost l explained what else he needed to build external networks. His feedback was thanks lan for working it because l had no idea? He’s got three kid and it’s Christmas so he won’t be doing it on his break.

If it were me l would prepare an article on what building this thing is about and attach a parts list with prices in a thread. Then those who have decided to go ahead know the financial commitment and they proceed to buy the boards. They can also help each other assemble the boards. That’s me and that’s the way l do business.

This is “why” people come here.


Characteristic Inflation rate
Nov '22 7.1%
Oct '22 7.7%
Sep '22 8.2%
Aug '22 8.3%
Jul '22 8.5%
Jun '22 9.1%
May '22 8.6%
Apr '22 8.3%
Mar '22 8.5%
Feb '22 7.9%
Jan '22 7.5%
Dec '21 7%
Nov '21

[VinylGroove]

I went through to the best of my ability to document the parts, where I got them from and prices. I don't make any claims for this to be free of typos or errors and your parts selection, vendor and situation may differ from mine.
I did not include shipping or taxes as that will vary from place to place, but did add very rough estimates at the bottom, to arrive at my final estimated cost of $1845.53 USD before crossover cases or wiring and misc connectors and supplies.

So, they're cheaper than Kenrick's $11,000USD crossovers but not cheap by any means. Now I need to find a case/box worthy of the components and decide if I'm housing both PCBs in each speaker in 1 large case or in 2 smaller cases.

(I've attached a screenshot of the spreadsheet and also a copy of the excel spreadsheet that is zipped to allow upload here)

[mattking52]

All valid points.

I agree that this information would be useful in published form, and I do plan to put those cost estimates on my website in the upcoming FAQ pages. I applaud VinylGroove for posting the breakdown of the costs for his 4343 variant, as this is and also Ian for bringing this up. People should be informed, I completely agree. I would not advocate for anyone to purchase the boards if they were unaware and/or unprepared for the magnitude of the parts cost.

I've had lots of folks who were on the fence about buying the boards reach out to me (via email, etc.) to get a sense of what the costs of the parts will be, and I've been very up front with everyone who has asked that it can cost in the neighborhood of $2k total for boards + parts on a full passive configuration, and about $1500 for a biamp configuration. That definitely jives with VinylGroove's breakdown below.

The fact is that it's always been an expensive proposition to build a charge-coupled network, especially in a full passive configuration (and the current economic situation makes it more expensive, no doubt). As Greg Timbers said on this forum years ago, "It cost a bloody fortune to implement as it requires 4 times the capacitance and double the capacitor parts count. The network size gets huge as well. In spite of this, I have never heard a capacitor type that didn't improve (or change) including the nearly perfect teflon variety." The PCBs do add additional expense, but also save the user the hassle of point-to-point wiring, hot glue, and lessen the potential for wiring mistakes. That savings in time will justify the cost for some customers; I've certainly gotten this feedback from some folks who have finished or are in progress with their builds. At the end of the day, the cost of the upgraded charge-coupled networks (the success stories are well documented here on Lansing Heritage) is much smaller than the market value of the 43xx series monitors, but it is a non-trivial expense nonetheless.

Irrespective of the month-to-month rates of inflation, the cost of manufacturing here in the U.S. is not dropping - the costs (and lead times) are actually increasing daily... I deal with it in my main job every day. Hi-Fi companies are continuing to hike their prices too; I just got an email the other day from a local hi-fi dealer saying that a number of their brands (including the Manley gear) are implementing 10-20% price increases across the board starting Jan 2023.

Shipping is also expensive... everything's just expensive. Fabricating these boards was no exception, especially in the quantities that a small outfit can afford to order. I do include the cost of shipping with the purchase of the boards in an attempt to ease the burden on the international customers in particular.

I am exploring some options for trying to offer kits of parts in a more economical way in the future, but we will see how that goes.

[Ian Mackenzie]

I went through to the best of my ability to document the parts, where I got them from and prices. I don't make any claims for this to be free of typos or errors and your parts selection, vendor and situation may differ from mine.
I did not include shipping or taxes as that will vary from place to place, but did add very rough estimates at the bottom, to arrive at my final estimated cost of $2014.05 USD before crossover cases or wiring and misc connectors and supplies.

So, they're cheaper than Kenrick's $11,000USD crossovers but not cheap by any means. Now I need to find a case/box worthy of the components and decide if I'm housing both PCBs in each speaker in 1 large case or in 2 smaller cases.

(I've attached a screenshot of the spreadsheet and also a copy of the excel spreadsheet that is zipped to allow upload here)


I am sure your disclosure will be much appreciated.

FWIF l have provided the option of conventional capacitor of specific varieties where cost is price prohibitive. On this type of network a charge coupled crossover uses two capacitors with double the value. With large values it’s prohibitive.

What l have done and it’s endorsed in some JBL networks is to use dual NPE bypassed back to back with 0.01uF PP bypass capacitors and change couple. The real deal on the UHF is where it’s most beneficial.

If you want to you can upgrade it later you and see if you can hear the difference. I give people a choice.

[Ian Mackenzie]

Hi Matt,

Thank you for posting. I don’t think there is a justification for pricing your pcb offer relative to the overall cost of these networks. Have you in fact checked if anyone is in fact offering pcbs to the diy audio community at your prices? This is a valid concern by people looking at the price of your pcb offer.

https://www.audioheritage.org/vbulletin/showthread.php?24283-4344-Mk-II-network

In the link above is a schematic of the last iteration of the 4344 called the 4344mk11 which was an improvement on prior systems. I also use this system’s mid high frequency array.

The reason l bring this to the attention of forum members is that JBL has demonstrated the use of their charge coupled network with different capacitor types to enable production of that network in this system. In this network JBL are using NPE and Mylar capacitors bypassed by small value PP film capacitors using the charge coupled approach.

I have adopted this approach with parts lists for people wishing to clone this system and they are quite happy with it. The overall cost is significantly less than using the Solen 250 volt Fast caps. I believe the crossover pcb is considerably smaller and therefore also reducing cost.

As you are no doubt are aware group buys of pcbs are a regularly occurrence on Diyaudio.com. As costs are going up a group buy would be a welcome initiative with a view to reducing the cost.

[Robh3606]

Charge Coupled networks have always been expensive to build. I have been using them for years in my DIY and clone builds. One of the easiest ways to lower the cost is too look at cored inductors and rated voltages on the capacitors.

If you look at the capacitor pricing the difference between 250V vs 400V is significant. The 400V parts are almost double the cost. If you look at JBL specs for the Capacitors in the stock networks it's 100 volts. It's obvious that the 250 volt parts are more than adequate.

Looking at the 4344 Mk 2 JBL doesn't always use CC networks on the woofer. You can CC with NPE as Ian suggested or just use a bypassed film capacitor as an alternative. The NPE's are the most cost effective.

With inductors JBL has used cored inductors in almost all of their designs. Just take a look at the referenced 4344 Mk2 parts list as an example. It can be difficult to find air cores that match the specified DCR of the stock cored inductors. You can save considerable cash using cored inductors as compared to air cores with the same DCR values. Just verify that the power ratings are reasonable.

Look at the 5.6Mh in the Aux PCB parts list. It is listed as 6.5 in the parts link and the price on the 3Mh looks a bit high. Much more costly than the 5.6/6.5 Mh??

If you can't find the exact value Inductor you can purchase the closest higher value and take some turns off providing you have a way to measure for Inductance.

Rob :)

[VinylGroove]

Look at the 5.6Mh in the Aux PCB it 6.5 in the part link and the price on the 3Mh looks a bit high. Much more costly than the 5.6/6.5 Mh.

If you can't find the exact value Inductor you can purchase the closest higher value and take some turns off providing you have a way to measure for Inductance.

Rob :)

For the 5.6Mh inductor, I verified the link is correct for a 5.6. They have a dash in the url that makes it look like 6.5 but it's followed by "5_6" which is for the 5.6.
https://solen.ca/en/products/solen-perfect-lay-air-core-inductors-s125_6-5_6mh-12awg-inductor


BUT, on the other Aux board inductor I bought one 10x the size I need! It turns out the location of a decimal is important! Who knew?


Thank you for catching the price on that! I updated the spreadsheet and screenshot earlier in this thread.

[Ian Mackenzie]

The other thing is building an external network is more expensive than an internal network. Those six L pads add to the overall cost as do the additional cable terminals. I have built a number of these things and it’s surprising just how much the hardware adds to the cost.

Therefore if you are working to a budget putting the network inside the enclosure will save you money. Think about the rest of your system and then determine what you can justify. As Rob has said look at the inductors for alternatives. The Dayton Audio resisters are perfectly satisfactory instead of the Mills resisters and will save you money.

[VinylGroove]

The other thing is building an external network is more expensive than an internal network. Those six L pads add to the overall cost as do the additional cable terminals. I have built a number of these things and it’s surprising just how much the hardware adds to the cost.

Therefore if you are working to a budget putting the network inside the enclosure will save you money. Think about the rest of your system and then determine what you can justify. As Rob has said look at the inductors for alternatives. The Dayton Audio resisters are perfectly satisfactory instead of the Mills resisters and will save you money.


One of the great things about these PCBs is the ease of bypassing/eliminating the L-Pads with a fixed resistor, once you determine the desired resistance you want in your system. And it's easily reversible.

[Ian Mackenzie]

One of the great things about these PCBs is the ease of bypassing/eliminating the L-Pads with a fixed resistor, once you determine the desired resistance you want in your system. And it's easily reversible.


It’s marketed as a feature.

This is the thing :

You loose all flexibility in setting the levels once you do that.
There is quite a lot of re work in implementing that change and the L pads you have installed become redundant. Those L Pads are US$75.00 on the parts list.

Secondly you have to be able to accurately determine the L pad levels. Then disconnect the L pads completely and then measure them. There’s measurement tools and whole procedure to get right that may require several iterations over time. Are your drivers working properly in the first place? Across a population of pcb purchasers are they going to have the levels set consistently?

There is no sonic audiophile virtue in removing the L pads.

Yes the pcb holes are there but the onus is put on the purchaser to figure all this out and do it.

[Ian Mackenzie]

For those interested in the whole topic here is an FYI.

The link below is a pictorial of the stock 3145 network used in the popular JBL 4344 and 4345 systems.

I did this over ten years. There is a lot of detail to be addressed in disconnecting or removing the stock crossover and routing cables to an external crossover if that’s what you want to do. It’s one thing to look at it on paper but in terms of opening these things up there’s a lot going.

None of this has been fleshed out for these pcb purchasers with images.

If it were me l would be running several tutorials for an awareness, what’s involved and how to go about it so the customer does get it right. If l was paying those pcb prices l would be expecting that. It’s about being committed to following it through. It’s not just the sale.

https://www.audioheritage.org/vbulletin/showthread.php?13930-JBL-3145-stock-crossover-A-pictorial

[VinylGroove]

I don't want to derail into a philosophical discussion on pricing, as the seller sets the price and the free market decides if people buy and how many. I feel they're a great value (as long as they end up with a good result, that is ;)

If anyone is wondering, Echo reached out to me and has offered support on multiple questions post-sale and even offered to give some thought to designing a way to switch them back and forth between biamp and full passive, so the support is there thus far.

As for the fixed resistors, you're right about the L-pads being more flexible. The biggest consideration would be if you change the room or speaker placement or gear and may want to adjust those settings again. I'm just annoyed at my vintage L-pads because they are the only issue with my current 4343's. Deoxit resolved it, but that's a bandaid and the issue will return. A stepped switch with multiple resistors in a ladder configuration would be interesting and I considered it but decided to stick with the proposed parts list.

[Charles0322]

For those interested in the whole topic here is an FYI.None of this has been fleshed out for these pcb purchasers with images.If it were me l would be running several tutorials for an awareness, what’s involved and how to go about it so the customer does get it right. If l was paying those pcb prices l would be expecting that. It’s about being committed to following it through. It’s not just the sale. https://www.audioheritage.org/vbulletin/showthread.php?13930-JBL-3145-stock-crossover-A-pictorialFor us building several pairs of these large boxes, it has been really easy to deal with EM. The pricing is very fair in regards to the quality.. not sure where all the critique is coming from. Or imagined problems with implementation.It seems for someone saying "If I was paying" you have quite a lot to say.. as someone who did pay I have nothing but praise for the communication, the actual quality of the product and effort in supplying us these types of parts for our builds.

[mattking52]

If you look at the capacitor pricing the difference between 250V vs 400V is significant. The 400V parts are almost double the cost. If you look at JBL specs for the Capacitors in the stock networks it's 100 volts. It's obvious that the 250 volt parts are more than adequate.

Rob - I'm glad you brought up 250V vs. 400V capacitors, as it's something worth discussing.

From a technical standpoint, it's absolutely true that a 250V capacitor is more than adequate in these circuits, as you pointed out. In fact, I initially started the board layout with Solen's "PA" Fastcap line (250V) in mind, based on the smaller size, the sufficient voltage rating relative to the stock caps, and what I *assumed* would be cheaper parts. However, a few things immediately came to light:

- Solen's PA (250V) line is not carried at most of the bigger parts vendors - Parts Express, Parts Connexion, or Madisound. They only carry the PB (400V) line.
- If you go direct to Solen Canada's website (solen.ca), the 250V PA parts are actually the same price, or in some cases *more expensive* than, their 400V PB equivalents. As befuddling as this is, it's true! For example:
https://www.solen.ca/en/products/solen-fast-capacitors-pa2200-22uf-250v-metallized-polypropylene-film (22uF 250V PA series - $12.59 CAD each)
https://www.solen.ca/en/products/solen-fast-capacitors-pb2200-22uf-400v-metallized-polypropylene-film (22uF 400V PB series - $11.32 CAD each)
https://www.solen.ca/en/products/solen-fast-capacitors-pa220-2_2uf-250v-metallized-polypropylene-film (2.2uF 250V PA series - $5.19 CAD each)
https://www.solen.ca/en/products/solen-fast-capacitors-pb220-2_2uf-400v-metallized-polypropylene-film (2.2uF 400V PB series - $4.80 CAD each)

Since the Solens have a good reputation in charge-coupled applications on Lansing Heritage, and because it's what JBL uses in their latest and greatest charge-coupled networks (they're what I use in my own setup also), I chose to target those for the board design. Since there was no price benefit on the Solen 250V over the 400V, and because the 400V are more widely available from vendors, I chose to size the footprints for the 400V series and include them in the "default" parts list. The user manual also states that customers can choose to pull from the default parts list, or substitute parts of their own choice, as long as they verify the dimensions and fit.

That said, there are less expensive 250V polypropylene caps from Dayton that would be perfectly fine in this application. As alluded to in previous posts, there are other options (NPE, mylar, etc.) that can be leveraged to lower cost as well. The boards provide a nice platform for experimentation, since the larger PB-sized footprints should be big enough to accommodate a variety of caps, so people can feel free to choose what they like in terms of preference, budget, etc. :)

[Ian Mackenzie]

I don't want to derail into a philosophical discussion on pricing, as the seller sets the price and the free market decides if people buy and how many. I feel they're a great value (as long as they end up with a good result, that is ;)

If anyone is wondering, Echo reached out to me and has offered support on multiple questions post-sale and even offered to give some thought to designing a way to switch them back and forth between biamp and full passive, so the support is there thus far.

As for the fixed resistors, you're right about the L-pads being more flexible. The biggest consideration would be if you change the room or speaker placement or gear and may want to adjust those settings again. I'm just annoyed at my vintage L-pads because they are the only issue with my current 4343's. Deoxit resolved it, but that's a bandaid and the issue will return. A stepped switch with multiple resistors in a ladder configuration would be interesting and I considered it but decided to stick with the proposed parts list.


But is a free market and high prices invite completion.

I speak for someone who isn’t a forum member and has asked for a justification of the pricing?

This is quote l have been provided by this person from a reputable online line pcb fabrication business for the same basic specifications of the bi amp is pcbs. The fabricator is Pcway.com

FYI

A quote on price, build and shipping of quantity 10 pcbs 320mm x 240mm per the bi amp pcb shipped to the reseller is US$206.20 plus shipping $91.31 Total $297.41

Assuming supply of two Biamp or PCB US$30.00 each plus shipping locally US$20.00 = US$80.00 cost per pair of these boards. You sell with shipping at US$279.00 per.

This means your net profit on the sale of two pcbs is US$220.00.

This is the retail online sale price of a part of a audio diy project. Not a finished retail product in Beverly Hills. Does that represent good value? In AUD x 1.45 = AUD $404.00 plus fees for two. Is this the price for the privilege to assemble a passive crossover network on two twenty dollar pcbs?

For purposes of comparison not long ago l purchased a Douglas Self stereo preamplifier pcb set. This is complex project to assemble with hundreds of parts designed by an expert.

Here is the correspondence. Included was a folder of pdf documents and pcb overlay to facilitate assembly.

This is a great sounding preamp that is easy to build. A single PCB kit is $50 US.

Shipping outside the US is $25 via First Class Post.
That means for one kit $50 + $25 = $75 to ship to ship inside the US.

If you buy a 2nd kit the shipping on that 2nd kit is free. That means 2 kits ...

Outside the USA $100 US (ie: 2 x $50) + $25 (pack & ship First Class mail) = $125 US

The kit amounts to ...

#1) the main PCB
#2) the 5 x 1 IO PCB,
#3) Front panel selector switch PCB
#4) Power supply PCB (120v but can be easily modded to 230v)
#5) and 2 (hard to get) OEM quad RCA phono connector blocks

The BOM can be fulfilled by Mouser and Digikey

[rusty jefferson]

Don't have a dog in this fight, as they say, but the 4 board set for $329 doesn't seem outrageous to me. I don't see it as boutique, but rather a niche product. How many of these things could they possibly sell in a lifetime? Apparently, not enough that someone else wants to start making them.

I don't know, but if you want to talk manufacturing cost/profit ratio, what's it cost Solen to make those 22mfd capacitors they sell direct to consumers for CA$12.50 each?

[VinylGroove]

But is a free market and high prices invite completion.

I speak for someone who isn’t a forum member and has asked for a justification of the pricing?

This is quote l have been provided by this person from a reputable online line pcb fabrication business for the same basic specifications of the bi amp is pcbs. The fabricator is Pcway.com

FYI

A quote on price, build and shipping of quantity 10 pcbs 320mm x 240mm per the bi amp pcb shipped to the reseller is US$206.20 plus shipping $91.31 Total $297.41

Assuming supply of two Biamp or PCB US$30.00 each plus shipping locally US$20.00 = US$80.00 cost per pair of these boards. You sell with shipping at US$279.00 per.

This means your net profit on the sale of two pcbs is US$220.00.

This is the retail online sale price of a part of a audio diy project. Not a finished retail product in Beverly Hills. Does that represent good value? In AUD x 1.45 = AUD $404.00 plus fees for two. Is this the price for the privilege to assemble a passive crossover network on two twenty dollar pcbs?

For purposes of comparison not long ago l purchased a Douglas Self stereo preamplifier pcb set. This is complex project to assemble with hundreds of parts designed by an expert.

Here is the correspondence. Included was a folder of pdf documents and pcb overlay to facilitate assembly.

This is a great sounding preamp that is easy to build. A single PCB kit is $50 US.

Shipping outside the US is $25 via First Class Post.
That means for one kit $50 + $25 = $75 to ship to ship inside the US.

If you buy a 2nd kit the shipping on that 2nd kit is free. That means 2 kits ...

Outside the USA $100 US (ie: 2 x $50) + $25 (pack & ship First Class mail) = $125 US

The kit amounts to ...

#1) the main PCB
#2) the 5 x 1 IO PCB,
#3) Front panel selector switch PCB
#4) Power supply PCB (120v but can be easily modded to 230v)
#5) and 2 (hard to get) OEM quad RCA phono connector blocks

The BOM can be fulfilled by Mouser and Digikey

Kindly stop with the complaints about price in this thread, it's not helpful and is kind of weird. I'm a happy customer working on a project that I'm very excited about and would like to proceed with that kind of focus and enjoyment of the hobby. Thank you.

[Ian Mackenzie]

Well it’s interesting you say that…Lol

Why are you here? It wasn’t for sale on the Lansing Market Place.

However, l did have a look at the website after l was made aware of it. On further investigation l determined that the parts in the parts list did not coincide with the parts in the 4343 JBL model crossover schematic. Why? Oddly no schematic is published or available on the Echo Mountain Audio Website. I have not had time to look at anything else.

I am familiar with the technical aspects of these systems so l modelled the parts in the parts list electronically. The results did not match the JBL published data in all instances. In view of this l kindly reached out to Echo Mountain Audio to let them know. Ultimately Echo Mountain Audio accepted there were problems and that they had not checked or understood the information provided on the JBL schematic tech sheet. I then validated a modified schematic for you so it would work properly. As it turns out the none of the work was peer reviewed or tested by a 3rd party before it was advertised. I am not aware if the parts listed on the website have been updated or an error notice placed on the website.

Is it worth the asking price? Well that’s in the eye of the beholder on EBay. What you don’t won’t hurt you will it!

So as it is you are the recipient of a lot of my time.

Thankyou coming here.

[VinylGroove]

Well it’s interesting you say that…Lol

Why are you here? It wasn’t for sale on the Lansing Market Place.

However, l did have a look at the website after l was made aware of it. On further investigation l determined that the parts in the parts list did not coincide with the parts in the 4343 JBL model crossover schematic. Why? Oddly no schematic is published or available on the Echo Mountain Audio Website. I have not had time to look at anything else.

I am familiar with the technical aspects of these systems so l modelled the parts in the parts list electronically. The results did not match the JBL published data in all instances. In view of this l kindly reached out to Echo Mountain Audio to let them know. Ultimately Echo Mountain Audio accepted there were problems and that they had not checked or understood the information provided on the JBL schematic tech sheet. I then validated a modified schematic for you so it would work properly. As it turns out the none of the work was peer reviewed or tested by a 3rd party before it was advertised. I am not aware if the parts listed on the website have been updated or an error notice placed on the website.

Is it worth the asking price? Well that’s in the eye of the beholder on EBay. What you don’t won’t hurt you will it!

So as it is you are the recipient of a lot of my time.

Thankyou coming here.

I definitely benefitted from your comments because you pointed out a price on the list I posted was off on one of the items and I bought the wrong one. So you saved me some grief and a lot of waiting since I was able to order the correct part - still laughing that I bought an inductor 10x the size of what I needed. So thank you for that!

I just don't think it's appropriate to bash each other on a public forum over something like pricing, I think that's best left to a private conversation because they never end well when it's aired publicly.

FYI, I've been an active member of hundreds of forums since the 90's and owned some myself as well. I've surely helped millions of people with my chronic overthinking and incessant need to delve into details and share findings as I do that to decompress, and I rotate between a lot of hobbies and interests. That is what makes forums such a great resource - and when someone makes an error, it gets called out by other experts so honestly forums are the best place to obtain knowledge in many cases because "none of is as smart as all of us". When a discussion is had and a consensus is made among those with expertise, that is incredibly valuable and appreciated. I've benefitted a lot from this forum for sure.

[Ian Mackenzie]

I’ve just done a cart list for the bi amp only change coupled 4345 final schematic.

Pcb parts only
On my list l selected a Jantzen laminate core 1.8mh. All other inductors air core
All Solen capacitors
Dayton audio grade resisters

The total parts cost was US$309.64 or a pair of networks excluding shipping.

Most forum members with these systems have already built or had built by Giskard charge coupled networks.

If you are new to all this l would look at installing the network internally to save a heap on money and space taken up by an external network. An external network won’t make it sound any better. Wiring faults are more likely with external connectors and cables. The pcb should fit on the inside of rear access panel. An external crossover will need a reasonable sized enclosure. Most people who have done this either put them atop the loudspeaker system or beside it. Will that fit the room decor or WAF is something to consider.

Given these particular pcbs add almost 100% to the overall cost and if located internally (not mens eye candy) a conventional plywood crossover assembly would be a significant cost saving.

[VinylGroove]

I've got all of my parts to build a full passive crossover setup now, but doing this internally with just the biamp board would allow me to complete it next week on the holiday break. (I can always move to external later)

To any who have done this are there lessons learned on where the best location to install the PCB inside the box is?
My gut reaction would be to have an edge of the PCB against the floor of the speaker box, but maybe that would be bad for vibration and it would be better "floating" on the standoff mounts.

Here are a couple of standoff options:
https://www.amazon.com/BCQLI-Console-Motherboard-Fixed-Plastic/dp/B07H2BGGSF
https://www.amazon.com/gp/product/B08MSYHW9M/

[Ian Mackenzie]

Your on the right track.

Those stand offs look fine.

Provided the parts are securely mounted on the pcb you don’t have to worry about vibrations. The floor of the enclosure will be fine and probably the easiest location in my experience. You could just sit it in there for now.

Tips.

Disconnect the wires in the binding posts marked internal and connect your crossover pcb via new cables to the internal binding posts.

Edit . Your system is the 4343. So you will need to search around for pics of the 4343 crossover network.

There are wires from the stock crossover to the L pads and return wires from the L pads as l recall. What you need to do is determine the correct wires for the L pad tabs (1), (2), (3). Draw out the existing wiring on a sheet of paper and label all the wires. Then refer to your pcb instructions. Take it step by step with a glass of red wine and under no circumstances get interrupted.

I suggest you take a number of pics on your Smart phone before dis assembly of the stock crossover. It will save your marriage by averting a major meltdown if you become confused, agitated and loose your shit! Lol.

Edit. Because the internal L pads for the MID and the HF are 16 ohms they won’t be compatible with this pcb. So you will need to wire up you’re 8ohm L pads. What l suggest you do for now is put the Lpads through the ports on long enough cables so you can adjust then from outside. Replacing the existing L pads is a bit involved.

[VinylGroove]

Your on the right track.

Those stand offs look fine.

Provided the parts are securely mounted on the pcb you don’t have to worry about vibrations. The floor of the enclosure will be fine and probably the easiest location in my experience. You could just sit it in there for now.

Tips.

Disconnect the wires in the binding posts marked internal and connect your crossover pcb via new cables to the internal binding posts.

See my pictorial link l posted earlier for a guide to how the L pads are wired to the stock pcb.

There are wires from the stock crossover to the L pads and return wires from the L pads as l recall. What you need to do is determine the correct wires for the L pad tabs (1), (2), (3). Draw out the existing wiring on a sheet of paper and label all the wires. Then refer to your pcb instructions. Take it step by step with a glass of red wine and under no circumstances get interrupted.

I suggest you take a number of pics on your Smart phone before dis assembly of the stock crossover. It will save your marriage by averting a major meltdown if you become confused, agitated and loose your shit! Lol.

Ah crap, I forgot about the Lpads entirely. Can the new replacement Lpads line up on the front baffle with the same coin slot knobs for OEM JBL appearance?

https://www.parts-express.com/L-Pad-50W-Mono-3-8-Shaft-8-Ohm-260-252
https://www.parts-express.com/L-Pad-50W-Mono-3-8-Shaft-16-Ohm-260-254

[Ian Mackenzie]

I don’t know. You will have to measure it out.

If the internal L pads are the same power rating it should be okay.

However, l don’t recall how to remove the L pad board? I suggest you take some internal pics of the L pads.

These pics show the way.

There are plenty of people with 4343 so if you get stuck they might chime in.

Open a new thread and call it 4343 upgrade help needed.

[mattking52]

Ah crap, I forgot about the Lpads entirely. Can the new replacement Lpads line up on the front baffle with the same coin slot knobs for OEM JBL appearance?

https://www.parts-express.com/L-Pad-50W-Mono-3-8-Shaft-8-Ohm-260-252
https://www.parts-express.com/L-Pad-50W-Mono-3-8-Shaft-16-Ohm-260-254

I replaced the L-pads in my 4344s before I went to charge-coupled networks in an external enclosure. It is possible to get the OEM look, flush with the front baffle, but it requires the new L-pads with the 1" shaft (the 3/8" are too short), and custom spacers - the existing ones on the back side of the L-pad shaft will be too short with the 1" shaft. I had to get new standoffs and cut them down to a custom size, but it wasn't hard to figure out when measuring the shaft of the original L-pad and taking the difference between that and the 1" shaft. If I had the dimensions for you, I'd pull them up, but it's been so long that I don't think I have a record of what exactly the new spacer length was. If I find it, I'll let you know.

I have some other thoughts about mounting internally, too, which I will come back with later (hard to keep up with the forums with all the end of the year work madness going on). I also have a customer who is almost done with his build who is mounting his boards internally (4345s, so not exactly the same as yours), but he'll be sending pictures, etc., and possibly posting here, so his build might give you some ideas/inspiration. In general, though, I agree that sitting it on the floor of the speaker enclosure - as long as it isn't vibrating against any hard surfaces - would likely be just fine.

[VinylGroove]

Looks like I'd have to remove the foilcal on the front to get to the screws.

Maybe for this first iteration of crossover upgrade I'll keep the stock Lpads as they are, install the biamp board internally, upgrade binding posts and see how that goes.

[Ian Mackenzie]

Just to get it going put the new L pads on long cables so you can pull use L pads in and out of the ports. You probably won’t have time to mess around with the stock L pads.

In hindsight if the stock 16 ohm L pads and the stock 4343 crossover schematic was used neither of you would have had to deal with this or any of the problems you’ve had to date.

That’s the lesson that needs to be learnt here.

[Ian Mackenzie]

Looks like I'd have to remove the foilcal on the front to get to the screws.

Maybe for this first iteration of crossover upgrade I'll keep the stock Lpads as they are, install the biamp board internally, upgrade binding posts and see how that goes.

That’s a bummer.

What l would do is leave it for now.

Try it as l posted with you new L pads on long cables.

Then talk to Matt or me about a revision of the parts so you can use the existing 16 ohm L pads on the MID and HF. It’s just hard work otherwise and l would risk peeling off the foilcal.

[VinylGroove]

Just to get it going put the new L pads on long cables so you can pull use L pads in and out of the ports. You probably won’t have time to mess around with the stock L pads.


That's not a bad idea running them out the bass ports.

I would also need the 9V battery holder mounted on the back of the speaker since I don't want it to leak inside or be inconvenient to change in the future. I think I'll run the 9v wire through the factory internal/external crossover switch hole.

Another idea is I could enlarge that hole and also run Lpad wires out of it to a small board mounted on the back of the speaker and not have to modify the front Lpads at all. Kind of a hodge podge but it would work and keep the stock front appearance.

(Note the mid L-pad is 16ohm on the replacements I have)

[Ian Mackenzie]

That’s an interesting thought.

If you use a good quality lithium 9v battery it should be fine.

If can change the two 68R resisters in the mid filter to 47R your internal mid L pads will work with the attenuation you need normally.

I’m having a look at your horn filter

[Ian Mackenzie]

I don’t know what parts values Matt finally ask you to put in the HF filter.

But wire up your internal 16 ohm HF L pad we send me via email details of the parts you have for that filter and l will advise on any changes if necessary.

It can be sorted out. Okay

[mattking52]

That's not a bad idea running them out the bass ports.

I would also need the 9V battery holder mounted on the back of the speaker since I don't want it to leak inside or be inconvenient to change in the future. I think I'll run the 9v wire through the factory internal/external crossover switch hole.

Another idea is I could enlarge that hole and also run Lpad wires out of it to a small board mounted on the back of the speaker and not have to modify the front Lpads at all. Kind of a hodge podge but it would work and keep the stock front appearance.

(Note the mid L-pad is 16ohm on the replacements I have)

I support this configuration... on the condition that you use that exact battery. LOL!

[mattking52]

That's not a bad idea running them out the bass ports.

I would also need the 9V battery holder mounted on the back of the speaker since I don't want it to leak inside or be inconvenient to change in the future. I think I'll run the 9v wire through the factory internal/external crossover switch hole.

Another idea is I could enlarge that hole and also run Lpad wires out of it to a small board mounted on the back of the speaker and not have to modify the front Lpads at all. Kind of a hodge podge but it would work and keep the stock front appearance.

(Note the mid L-pad is 16ohm on the replacements I have)


I don’t know what parts values Matt finally ask you to put in the HF filter.

But wire up your internal 16 ohm HF L pad we send me via email details of the parts you have for that filter and l will advise on any changes if necessary.

It can be sorted out. Okay

Ian - VinylGroove has new 16 ohm L-pads for the MF section, and the filter is tuned for that (you and I looked at this - it's those same values - and thanks again for catching that mistake and verifying my changes). It's the HF filter that currently uses an 8 ohm L-pad instead of the stock 16 ohm. The UHF uses 8 ohm L-pads in both cases.

If he goes with his external mounting idea, he is good with the new L-pads that he has on hand. He and I have been in close communication via email.

[VinylGroove]

A small surface mount "project box" like this could easily be mounted to the back of the speaker to house the Lpads

https://www.amazon.com/BUD-Industries-CU-477-Aluminum-Econobox/dp/B005T7R82W/
https://www.amazon.com/Otdorpatio-Junction-Waterproof-Electrical-200x120x75/dp/B08P55BZDH/

[Ian Mackenzie]

There you go. A good work around.

[Ian Mackenzie]

Ian - VinylGroove has new 16 ohm L-pads for the MF section, and the filter is tuned for that (you and I looked at this - it's those same values - and thanks again for catching that mistake and verifying my changes). It's the HF filter that currently uses an 8 ohm L-pad instead of the stock 16 ohm. The UHF uses 8 ohm L-pads in both cases.

If he goes with his external mounting idea, he is good with the new L-pads that he has on hand. He and I have been in close communication via email.

Apparently.

But those who wish to put the pcb inside and use the stock L pads will need a work around. This is your product. Good luck with it.

[mattking52]

Apparently.

But those who wish to put the pcb inside and use the stock L pads will need a work around. This is your product. Good luck with it.

Yes, future revisions will target a 16 ohm L-pad on the HF filter to avoid issues for those who want to use the stock L-pads on the 4341/4343. Trying to make the boards universal was an ambitious task, and of course it came with an initial hiccup, but we are working through it now. Gotta start somewhere.

The assistance you've provided has been much appreciated.

[VinylGroove]

I just realized I still need wire for each of the 4 drivers and the Lpads and 9v and to wire binding posts but the only wire I have on hand is 12awg belden speaker wire. I could reuse the existing wire to the drivers but I don't know if it will be long enough or how good that original JBL wire is.

Does any one know a US supplier that ships fast that has good OFC wire in various gauges for the above? (silver plated?)

This stuff has a good silicone jacket/tinned copper, available in 14, 16, 18awg
https://www.amazon.com/Fermerry-Stranded-Flexible-Silicone-Electrical/dp/B089D1741Z

This 6 conductor wire seems like it would be good to run out to the external Lpads
https://www.amazon.com/gp/product/B0B943FX4V/ref=ox_sc_act_title_5?smid=A14FQMU70R1AU5&psc=1

This Gear IT stuff has good reviews and available in 12, 14, 16, 18awg
https://www.amazon.com/Speaker-GearIT-Meters-Theater-Speakers/dp/B00HZWYP1G/

[Ian Mackenzie]

What l would do is make up a separate cable loom for each L pad. Use zip ties.

Don’t mix them together in the one jacket. This could effect the crossover performance and result in wiring mistakes.

https://www.amazon.com/Fermerry-Stranded-Flexible-Silicone-Electrical/dp/B089D1741Z

You don’t need anything thicker than 18 gauge for the horn and the slot L pads. Perhaps 16 gauge for the mid but over such a short distance not really necessary heavy gauge wire will be more difficult to solder properly because more heat and a bigger soldering iron is required to heat a joint up quickly. Otherwise you end up melting the cable insulation.

I suggest you also you some adhesive or screw down cable clamping (cable management) to provide strain relief on the connections to the pcb and the L pads. Otherwise the cable will stress the L pad tabs and or the pads on the Pcb.

This is where cable fatigue occurs and reliability problems. That would be a suggestion for a future iteration of the pcb.

[mattking52]

This stuff has a good silicone jacket/tinned copper, available in 14, 16, 18awg
https://www.amazon.com/Fermerry-Stranded-Flexible-Silicone-Electrical/dp/B089D1741Z



The wire at the link above will work great. As you and I discussed previously, I typically use 18 AWG for the HF and UHF, 16 AWG for the mid (feel free to use 18AWG, though), and larger speaker wire for the direct wiring to the woofer in a biamp configuration. I also use thicker speaker wire to the input of the crossover.

You will have no problem soldering larger than 18AWG gauge wire to these PCBs. I've done it many times, as have some other folks who are using them.

[Ian Mackenzie]

Yes, future revisions will target a 16 ohm L-pads on the HF filter to avoid issues for those who want to use the stock L-pads on the 4341/4343. Trying to make the boards universal was an ambitious task, and of course it came with an initial hiccup, but we are working through it now. Gotta start somewhere.

The assistance you've provided has been much appreciated.

Great.

What you need and must do quickly moving forward is to set up a jig for real loudspeaker driver load and voltage drive plotting of an authentic system with stock network in each case. The measurement needs to made at the driver terminals.

The best way to do this is to build up each system or borrow a stock system. This is what GT and Giskard did with the equivalent networks published on the LHS forums.

See the Nelson Pass JBL L300 crossover article. He used to design all the networks for ESS Loudspeakers in the 70’s. Talk to him about how to go about it.

Then test and plot each of your equivalent networks with a stock system. Confirm & Validate your equivalent networks with actual published results. There are no doubt people with stock systems who would volunteer to participate in this important step. Make sure you arrange for someone to built and test each system and validate per the above. Proof of compliance with any JBL network or system should be available before a customer completes a transaction.

None of this is difficult.

The assistance l have provided was a quick fix only for that particular customers circumstances. I have NOT validated or endorsed your pcbs product or any claims made by Echomountainaudio.com in any way shape or form.

Good luck

[Ian Mackenzie]

Hi Matt,

As a follow up to my above post the best and safest path for you and your fledging enterprise is to revert to the original stock JBL schematics or equivalent JBL schematics where applicable. People are familiar with these schematics and know what they are. Credit should be paid to the Greg Timbers and Giskard for the equivalent networks include the final 4344 equivalent network which you are currently using in your parts list.

People will still buy your pcbs and you will find the whole situation much easier to manage.

[VinylGroove]

I was going to use hot glue to support the weight of the large items but decided to go with some "Neutral Cure" Silicone, which doesn't give off any acid or harmful vapors and cures with some flexibility rather than getting hard and brittle with time.
I went with ASI 388 as it was specifically made for electronics and I can get it here quickly. Chip Quick is another one good for electronics but was delayed on shipping, as were the other neutral cure options.

Since I need to let the silicone cure for a full day, I roughed out some jigs to hold the pcbs in place and allow the component leads to hang down through the board without obstruction. I figure if I just silicone everything into place it will make flipping the board over and soldering up the back nice and easy. If there's an issue and I have to remove parts, it will be annoying, but that is the same with hot glue, and far worse with epoxy.

https://www.amazon.com/gp/product/B0063U2RT8
https://www.amazon.com/s?k=neutral+cure+silicone&crid=19LF63ES1C37F&sprefix=neutral+cure+silicon%2Caps%2C120&ref=nb_sb_noss_2

I know there are PCB jigs out there but most won't support a >12" PCB with extremely heavy components, so I just threw some plywood and 2x4's together that I had on hand and used finish nails which will make it easy to take PCBs on/off.

[Ian Mackenzie]

Great to see your having fun.

[VinylGroove]

I'm looking forward to having them done. I enjoyed some Christmas music through the 43's with stock crossovers while wrapping gifts today. Will dig into them next week (time permitting)
Once done, I'll do a final shootout between these 4343's and my 250TIs, then one of the two will be sold.

BTW - I think it's worth it to seal the low and mid woofers with new o-rings on these 43's. The bass and sound overall was much improved when I did. YMMV.
I bought 2 sets of o-rings from Kenrick so I have one spare set and the one that is in place now, totally worth it. But you could DIY with silicone pretty easily if you wanted to.

[Ian Mackenzie]

That’s a good point. I use cork gaskets on my clones.

Here is a link to the designers post. See the discussion on the 4345 and the 250

https://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post

[mattking52]

I'm looking forward to having them done. I enjoyed some Christmas music through the 43's with stock crossovers while wrapping gifts today. Will dig into them next week (time permitting)
Once done, I'll do a final shootout between these 4343's and my 250TIs, then one of the two will be sold.

BTW - I think it's worth it to seal the low and mid woofers with new o-rings on these 43's. The bass and sound overall was much improved when I did. YMMV.
I bought 2 sets of o-rings from Kenrick so I have one spare set and the one that is in place now, totally worth it. But you could DIY with silicone pretty easily if you wanted to.

You're gonna have some fun next week soldering them all up! I find it therapeutic, personally.

I put new O-ring gaskets on my 4344 drivers as well - including on the 2307 horn mounting interface.

[mattking52]

Oh, and Happy Holidays to all! It's 1:30pm here in California and the Christmas Eve festivities are kicking off soon.

[VinylGroove]

And a late Merry Christmas to all!

As I've been soldering and siliconing things together I messed up one inductor and realized I was short 2 resistors, so waiting another few days for those things to show up.

The metal box fits L-pads perfectly as far as thickness, so I bought a second one and am planning to use them on the back of the speaker - possibly with a 9 pin connector of some kind to let me put long or short cables on it if I chose. The box kind of resembles a Klon guitar pedal, if any of you are guitar players.
https://www.amazon.com/gp/product/B005T7R82W/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

But I've really been thinking about using resistors rather than L-pads. It seems like you could just do something like these below, with the middle resistor value being what you prefer for that driver, then you'd have +/- multiple steps in each direction.
Has anyone done this before?

Another option is to have a switch that could bypass the L-Pad and use 1 resistor that you could install and make it swappable.

The L-Pad just seems like a weak link and source of future issues but a stepped resistor ladder/knob situation could be fixed while still being tunable.

https://www.sparkfun.com/products/13099 - Rotary Switch Potentiometer Breakout
https://www.sparkfun.com/products/13006 - Decade Resistance Box

https://cdn.sparkfun.com/assets/learn_tutorials/3/4/1/product-shot.jpg

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQwRW8IcBKQpDCMXgxdVyPV-FRLNvDfCiHhkhZScZ0fyWrYWPztzY-cGpHYrPC6kOfwuPY&usqp=CAU

[VinylGroove]

A few photos of slow progress...

[mattking52]

But I've really been thinking about using resistors rather than L-pads. It seems like you could just do something like these below, with the middle resistor value being what you prefer for that driver, then you'd have +/- multiple steps in each direction.
Has anyone done this before?

The L-Pad just seems like a weak link and source of future issues but a stepped resistor ladder/knob situation could be fixed while still being tunable.


I think it's an interesting idea and something that you could look into in the future, but there are few things to keep in mind.

The switched attenuators you're showing in the photos are relatively easy to pull off since they are often meant for line-level applications and are sized for 1/4W to 1W metal film resistors. You'd need something more substantial for a speaker crossover application (remember the resistors in the crossover are rated for 12W+ each), and that could get prohibitively large.



Another option is to have a switch that could bypass the L-Pad and use 1 resistor that you could install and make it swappable.


It would have to be *both* resistors that get swapped if you want to dial up and down the attenuation properly, though - that's the trick. A L-pad is a variable voltage divider that maintains a constant load (8 ohm or 16 ohm, most commonly) as seen by the amplifier. If you could imagine turning the knob on a variable L-pad and picture the equivalent voltage divider in your head, both the series resistor leg and the shunt resistor leg would be changing in value to maintain that constant load. You can also see this by messing around with an L-pad calculator like this one: http://www.sengpielaudio.com/calculator-Lpad.htm

Overall, I think you'll find the new L-pads you've purchased from Parts Express to be reliable and an improvement on the old, dirty ones. I started with fresh ones three years ago now in my external crossover units, and they still have yet to exhibit any audible crackles when adjusting, channel dropouts, etc.

You'll find the adjustability very valuable when dialing the system in for the first time, and then can explore fixed resistor options if you wish. Just make sure you use a calculator such as the above and remember which impedance loads you're trying to match.

[mattking52]

A few photos of slow progress...

Looks like progress! That's awesome.

Just a thought (if you think you might display these in an external box in the future): if you don't like the look of bare wire, you can always mount the wire shorts, like the one you have across R13, on the bottom side of the board. Same thing for the L-pad and input/output wiring when you get there. I route it on bottom side of the board, bring it up through the plated through holes from the bottom side, and solder on the top. Keeps everything looking tidy.

[VinylGroove]

I think it's an interesting idea and something that you could look into in the future, but there are few things to keep in mind.

The switched attenuators you're showing in the photos are relatively easy to pull off since they are often meant for line-level applications and are sized for 1/4W to 1W metal film resistors. You'd need something more substantial for a speaker crossover application (remember the resistors in the crossover are rated for 12W+ each), and that could get prohibitively large.

It would have to be *both* resistors that get swapped if you want to dial up and down the attenuation properly, though - that's the trick. A L-pad is a variable voltage divider that maintains a constant load (8 ohm or 16 ohm, most commonly) as seen by the amplifier. If you could imagine turning the knob on a variable L-pad and picture the equivalent voltage divider in your head, both the series resistor leg and the shunt resistor leg would be changing in value to maintain that constant load. You can also see this by messing around with an L-pad calculator like this one: http://www.sengpielaudio.com/calculator-Lpad.htm

Overall, I think you'll find the new L-pads you've purchased from Parts Express to be reliable and an improvement on the old, dirty ones. I started with fresh ones three years ago now in my external crossover units, and they still have yet to exhibit any audible crackles when adjusting, channel dropouts, etc.

You'll find the adjustability very valuable when dialing the system in for the first time, and then can explore fixed resistor options if you wish. Just make sure you use a calculator such as the above and remember which impedance loads you're trying to match.

I didn't think about the 3rd terminal on the L-pads and it being more than just an inline resistor. Makes sense.



Looks like progress! That's awesome.

Just a thought (if you think you might display these in an external box in the future): if you don't like the look of bare wire, you can always mount the wire shorts, like the one you have across R13, on the bottom side of the board. Same thing for the L-pad and input/output wiring when you get there. I route it on bottom side of the board, bring it up through the plated through holes from the bottom side, and solder on the top. Keeps everything looking tidy.

I don't mind seeing the shorted wire and it makes it easier to see what you have going on if it's on the top, but something to keep in mind for future projects.

[mattking52]

I don't mind seeing the shorted wire and it makes it easier to see what you have going on if it's on the top

Fair point, indeed!

[Ian Mackenzie]

And a late Merry Christmas to all!

As I've been soldering and siliconing things together I messed up one inductor and realized I was short 2 resistors, so waiting another few days for those things to show up.

The metal box fits L-pads perfectly as far as thickness, so I bought a second one and am planning to use them on the back of the speaker - possibly with a 9 pin connector of some kind to let me put long or short cables on it if I chose. The box kind of resembles a Klon guitar pedal, if any of you are guitar players.
https://www.amazon.com/gp/product/B005T7R82W/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

But I've really been thinking about using resistors rather than L-pads. It seems like you could just do something like these below, with the middle resistor value being what you prefer for that driver, then you'd have +/- multiple steps in each direction.
Has anyone done this before?

Another option is to have a switch that could bypass the L-Pad and use 1 resistor that you could install and make it swappable.

The L-Pad just seems like a weak link and source of future issues but a stepped resistor ladder/knob situation could be fixed while still being tunable.

https://www.sparkfun.com/products/13099 - Rotary Switch Potentiometer Breakout
https://www.sparkfun.com/products/13006 - Decade Resistance Box

https://cdn.sparkfun.com/assets/learn_tutorials/3/4/1/product-shot.jpg

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQwRW8IcBKQpDCMXgxdVyPV-FRLNvDfCiHhkhZScZ0fyWrYWPztzY-cGpHYrPC6kOfwuPY&usqp=CAU

Well Nelson Pass wrote in his L300 article he could not detect any sonic change with the L pads. The advantage of a switching L pad is to have repeatable know changes in the driver level.

But do you need to mess with making a switched L pad?

A few tips.
No one setting of the L pads is going to necessarily going suit everyone in every situation. Some rooms will dictate lower or higher L pad settings. Equipment like a valve preamp and power amps in a bi amp situation could potentially need higher L pad settings.

So the flexibility of an L Pad in necessary.

However, you do need to have the drivers reasonably well matched in level. Right.

You can do this by ear by listening carefully to the tonal balance while turning the L pad of one driver at a time. Do this close to the loudspeaker to avoid the reverberation of the room. You can made adjustments to the Lpads later to deal with that.

For example with the horn and slot turned off listen for the mid cone driver and woofer blend that you prefer near the loudspeaker. The bass forms the foundation and much of the emotion in most music. So setting the bass / mid balance is a logical place to start.
By adopting this approach your ears are telling you what you are actually hearing. That’s important because loudspeaker placement in a room significantly effects the bass balance.

Then introduce the horn. By turning the horn L pad up and down you will be able to determine the blend you prefer in your environment. The upper mid range is what adds presence to tonal character. Then introduce the slot 2405. The slot 2405 adds details and ambiance to a musical presentation. By adjusting the 2405 L pad find the position you prefer.

Now the fun part. Recording your L pad preferences.

Ideally if you want to make a change to any of these L pad settings you need to record the changes. Using a Studio Six down load or similar you can make spot frequency test tones to measure increments of change in the L pads position. This can be done with a high degrees of accuracy using a low cost spl sound level meter. These digital spl meters can measure small changes in sound level accurately.

For example you might want to try increasing the horn up or down slightly but by a known amount. With a 5,000 hertz sine wave position the spl meter right in front of the horn lens about 2-3 inches from the meter. Turn the horn L pad up until the spl meter shows an increase of 1 db. You can then record you changes and go back to them later.

Caveat. This will send the family nuts. Send them off to a movie.

For the mid cone driver use a 600 hertz sine wave. For the 2405 use 8000 hertz. Remember to put the spl mic right in front of each driver.

With this process we are only interested in measuring the changes made in the spl level of each driver. You can’t easily do this with a room frequency analyser. They don’t have the resolution.

To determine the overall L pad attenuation of each L pad complete the following procedure.

Using the same spot frequencies for the mid, horn and 2405 each L pad at your preferred Lpad positions adjust the level to a round spl level in the spl meter. Say 90 db. Then turn the L pad up full. Note the change in db. Repeat for the other drivers.

Using this data you can now set the drivers on the other channel to exactly the same levels by turning the Lpad from full down by the measured amount.

You will find the tonal balance between the left and right channels much improved.

Once you have determined the L pad settings and the net attenuation of each L pad the fixed resister values can be determined.

https://www.instrumentchoice.com.au/instrument-choice/meters/environment-meters/sound-level-meters-1/0-200-sound-level-meters

I don’t claim to have been the inventor of this approach but this explanation is mine.

Copyright Ian Mackenzie Audio 2022.

[VinylGroove]

Well Nelson Pass wrote in his L300 article he could not detect any sonic change with the L pads. The advantage of a switching L pad is to have repeatable know changes in the driver level.

But do you need to mess with making a switched L pad?

A few tips.
No one setting of the L pads is going to necessarily going suit everyone in every situation. Some rooms will dictate lower or higher L pad settings. Equipment like a valve preamp and power amps in a bi amp situation could potentially need higher L pad settings.

So the flexibility of an L Pad in necessary.

However, you do need to have the drivers reasonably well matched in level. Right.

You can do this by ear by listening carefully to the tonal balance while turning the L pad of one driver at a time. Do this close to the loudspeaker to avoid the reverberation of the room. You can made adjustments to the Lpads later to deal with that.

For example with the horn and slot turned off listen for the mid cone driver and woofer blend that you prefer near the loudspeaker. The bass forms the foundation and much of the emotion in most music. So setting the bass / mid balance is a logical place to start.
By adopting this approach your ears are telling you what you are actually hearing. That’s important because loudspeaker placement in a room significantly effects the bass balance.

Then introduce the horn. By turning the horn L pad up and down you will be able to determine the blend you prefer in your environment. The upper mid range is what adds presence to tonal character. Then introduce the slot 2405. The slot 2405 adds details and ambiance to a musical presentation. By adjusting the 2405 L pad find the position you prefer.

Now the fun part. Recording your L pad preferences.

Ideally if you want to make a change to any of these L pad settings you need to record the changes. Using a Studio Six down load or similar you can make spot frequency test tones to measure increments of change in the L pads position. This can be done with a high degrees of accuracy using a low cost spl sound level meter. These digital spl meters can measure small changes in sound level accurately.

For example you might want to try increasing the horn up or down slightly but by a known amount. With a 5,000 hertz sine wave position the spl meter right in front of the horn lens about 2-3 inches from the meter. Turn the horn L pad up until the spl meter shows an increase of 1 db. You can then record you changes and go back to them later.

Caveat. This will send the family nuts. Send them off to a movie.

For the mid cone driver use a 600 hertz sine wave. For the 2405 use 8000 hertz. Remember to put the spl mic right in front of each driver.

With this process we are only interested in measuring the changes made in the spl level of each driver. You can’t easily do this with a room frequency analyser. They don’t have the resolution.

To determine the overall L pad attenuation of each L pad complete the following procedure.

Using the same spot frequencies for the mid, horn and 2405 each L pad at your preferred Lpad positions adjust the level to a round spl level in the spl meter. Say 90 db. Then turn the L pad up full. Note the change in db. Repeat for the other drivers.

Using this data you can now set the drivers on the other channel to exactly the same levels by turning the Lpad from full down by the measured amount.

You will find the tonal balance between the left and right channels much improved.

Once you have determined the L pad settings and the net attenuation of each L pad the fixed resister values can be determined.

https://www.instrumentchoice.com.au/instrument-choice/meters/environment-meters/sound-level-meters-1/0-200-sound-level-meters

I don’t claim to have been the inventor of this approach but this explanation his mine.

Copyright Ian Mackenzie Audio 2022.

Very useful info. Thanks. I never thought of doing that with individual drivers before.

This might seem odd to some people, but I only trust my ears to dial my system into 1 type of music at a time. I can always get that sounding great, but when I try something different I often realize I'm off in my settings, so I chase my tail. And when you compound the possibilities of 3 L pads, active crossover, preamp settings and for each of them it's both the levels you set and the relationship between them and others - and you can never trust a knob at 12 oclock to be the baseline either. :)

It will be interesting to use a noise generator and a mic/software to visually see the output at all freq levels to see where it's weak/strong - and get it as close to flat as possible, then my thought was to mostly use the preamp settings for bass and treble from that point on.

[mattking52]

And when you compound the possibilities of 3 L pads, active crossover, preamp settings and for each of them it's both the levels you set and the relationship between them and others - and you can never trust a knob at 12 oclock to be the baseline either. :)


So true. It's best to write down all the settings one uses when trying different configurations, to be able to return to the baseline.

The method that Ian describes above with the SPL meter on individual drivers is a good one; we followed a similar procedure on dialing in my 4344s when he visited my home a few years back, and I've done it subsequently when making tweaks to the system. The "software" SPL meter within REW (https://www.roomeqwizard.com/help/help_en-GB/html/splmeter.html) works well for this too, once you have a calibrated measurement microphone on hand. The handheld meters can obviously come in handy and are convenient when you don't want to bust out the laptop.

[Ian Mackenzie]

No problem.

This is diy and any goes.

On the sanity aspect note that a software based analyser is only a snap shot like a photo at a given moment in time. It not a true indicator of how your ears are being effected by the reverberation of your room which is at least half of what you hear.

This is because the loudspeaker emits sound not only directly to your ears but to most surfaces in your room. These reflections can be analogous to beams of light bouncing off the walls, floor and ceiling at all frequencies above the Schroder frequency of about 350-400 hertz. Because each reflected ray of sound has a delay interval typically 500-1000 ms you ears actually hear this. It’s like a shadow of the direct sound at a lower level.

For most people in their living room there is nothing you can do about this accept sit in a convenient position to listen to your loudspeakers.

Thus while from a technical standpoint a frequency graph might look like a good yard stick to make an assessment its actual use of it needs to have a place. Its not the final arbiter of what’s going to be enjoyable in your room.

I agree the old school bass and treble is useful.

From a scientific perspective Harman has come up with some guidelines called a room curve which is very similar to slight turn to the left of a treble control and modest bass boost. Of course Harman are selling you the idea that they discovered this curve so you buy their equipment and loudspeakers. But it’s been used for decades on traditional integrated amplifiers. The wankers.

In the end trust your ears and look at the curves only if you hear something wrong. It it ain’t wrong don’t mess with it .

Edit the 500-1000 ms referred to above is the time taken for the reflections in a small room (less than the size of a in door basket ball court or meeting hall) to reduce to an inaudible level. These reflections also tie in with the dispersion characteristics of a loudspeaker

Tip

Toe in your 4343’s about 10-15 degrees and place the enclosures 2.00 - 2.5 metres apart if possible. Tell your wife if she loves you then it’s okay.

Ideally the enclosures should be located at non equal distances to the rear and side walls. Your listening height is best if level with the lower lip of the 2308 horn lens. Pick a listening position equivalent to an equilateral triangle. Grab a glass of red wine and enjoy 😊 it.

[Ian Mackenzie]

This is the thing.

We all read reviews of phono preamps. It’s generally agreed the tighter the tolerance of variation with the RIAA equalisation get better. It’s an important performance criteria.

The measurement is +-0.5 db or better.

Generally we to are more susceptible to shifts in tonal balance over two or more octaves than small dips and peaks. So, if you have a four way loudspeaker the overall driver level balance analogous to a phono stage EQ. If the horn is above the mid by two db or more it’s going to effect the overall tonal balance. Given the caveat of your room on the acoustics you still need a degree of precision to set the L pads and match both the left and right channels.

If you use a room response analyser at 3 metres you’d be lucky to see +-3 db.

Therefore l recommend the above spl meter on a tripod. These digital meters can measure fractions of one db.

REW is good tool to obtain overall system measurements averaged across five or more locations near you listening position. It’s also good for near field driver response measurements. The most recent version of REW has tools for advanced acoustic analysis.
That’s not much use unless you can made real chances to your room acoustics.

If you have DIRAC or another home theatre receiver room calibration program you can experiment with the auto room set up.

[mattking52]

Therefore l recommend the above spl meter on a tripod. These digital meters can measure fractions of one db.

REW is good tool to obtain overall system measurements averaged across five or more locations near you listening position. It’s also good for near field driver response measurements. The most recent version of REW has tools for advanced acoustic analysis.
That’s not much use unless you can made real chances to your room acoustics.


FWIW, I used the actual SPL meter function in REW, with fixed frequencies pretty much exactly as you described above, and it worked well in tandem with my calibrated microphone on a microphone boom stand or tripod. The measurements were repeatable and high-resolution. The interface is modeled after the handheld SPL meters.
https://www.roomeqwizard.com/help/help_en-GB/html/splmeter.html

https://www.roomeqwizard.com/help/images/splmeter.jpg

[Ian Mackenzie]

Cool.

Like you said not everyone wants to stuff around with a lap top. The truth is looking at the population of people with audio as a hobby only a very small number use REW.

It’s intimidating if you don’t know what it means and most are not that committed to that kind of understanding. Those who do use REW are the visible 1 % who refer to it on forums.

[Ian Mackenzie]

Hi Matt,

Further issues have been identified in your pcb and parts list ref the 4315.

The components for the impedance conjugate network after the L pad has been emitted per the JBL 3114 and 3114A schematic.

The 2.5R resister after the L pad in the HF circuit is also missing.

Unfortunately the voltage drives don’t line up with real driver loads.

I am curious if you have fallen foul of your own attempt to come up with a one way same way pcb here? Good luck with your next pcb revision.

Incidentally for those interested in these networks it determined by Greg Timbers and Giskard that the money spent on charge coupled network for the 4343 was better spent upgrading the 4343 to the 4344 drivers. Then building a 4344 charge coupled network.

Ditto the 4340/4341.

Hence we never bothered with a 4343 charge coupled network. The effort was focused on the a 4344 change coupled network. The 2122H and the D16R2426 are significant improvements over the 2121H and the 2420 components. However, the 2122H mid driver and its recone kits are long since unavailable. The 2123H is the replacement and requires a 4344mk2 network.

A large number of charge networks for the 4344/4355 have been built by diy loudspeaker enthusiasts over the past 17 years.

Sans the 4350/4350B when Greg revisited the network in the early 1980’s which became the 4355.

The 4315 btw is a defunct system as the woofer and lower drivers have been unavailable for a very long time. Very few 4315 systems were actually produced.

So in rationalising the history of these systems the real justification for spending money on a charge coupled network for such a pcb is down to just three models.

The 4344, 4345 and the 4355. You seem to have omitted the 4344mk11 of which countless clones have been built.

I recommend you advise potential customers to visit the 43XX reference threads and my 4343-4344 upgrade thread before they decide what parts list to refer to.

Supported Systems
• 4315A/4315B
• 4340*
• 4341
• 4343/4343B
• 4344
• 4345
• 4350/4350B* • 4355*

Rationalised list
4344/4345
4344mk2
4355

This would simply your pcb and the parts considerably.

See attachments

[VinylGroove]

Ian, did you get the correct list of components for 4343? That attachment is for 4315 components which has some differences.

As for driver upgrades, I intend to keep this set of speakers stock except for crossovers and am really trying to keep everything reversible to original (which is why I’m tinkering with external L-pads and not messing with the foilcals). The speakers sound absolutely fantastic as they are and though I understand there are some components I could upgrade, I can't dismiss the benefits of charge coupled networks that I've read about, or the benefits of upgrading to fresh high end caps and resistors. Cost and ROI is another discussion, if I was going for maximum ROI I wouldn’t be buying 40 year old speakers in the first place :)

With that said, I haven’t soldered anything yet. I was about to but I’m waiting on 1 inductor before soldering. I do have 2 ohm resistors on hand to go inline on the MF L-pad but I don’t think a 2.5 ohm resistor on the HF L-pad was discussed.

[Ian Mackenzie]

On the 4343 l recall it was discussed but l don’t have the official updated parts list or any updates to the pcb.

I attached the above 4315 schematics for illustration purposes to identify the parts l referred to in my post. For an equivalent network those parts in the 4315 are required. They are after the L pads and ensures the network functions correctly when connected to the actual loudspeaker drivers.

Feedback and Recommendations.

1. I would also suggest a pcb revision so the cabling for the drivers coming from the pcb and not the L pad tab 1 and tab 2.

2. Secondly, l would recommend the pcbs be provided with quality pre soldered crimp style tab terminals and a labeled crimp connector cable loom for connection to the L pads and from the pcb to the mid, horn and 2405 drivers.

That way testing and disconnection of the pcb and the L pads is much easier for the constructor. Alternatively screw type terminals with spade terminals. It needs to be idiot proof so that incorrect connections by the constructor are eliminated. Labelling of supplied cables with a label maker would make it much for the constructor during installation of the crossover.

You don’t want to be looking back and forth to the instructions when installing the crossover, the cabling and the L pads.

This would make it much simpler for the constructor to wire up the L pads and connect the drivers to the pcb using quality crimp connectors (if my understanding of pcb is correct).

3A. Thirdly, on the size of the pcb to fit inside of the enclosures the final equivalent 4344 networks were assembled with the horn and uhf filters stacked above the mid filter board on nylon stand offs. It might not look as pretty but it’s a better approach. The two split pcbs could still be used for an external crossover network. The point is the constructor is not mandated into an external crossover implementation which will not suit all situations.

3B. For illustration in attached image is a HF & UHF filter boards below where l used nylon spacers with brass M5 screw threads as l recall. The mid filter board was mounted on top. Some cable strain relief ensures the integrity of all cable connections to the board.
More of an option but the pcb could be set up for bi or tri wiring back to the power amp. I didn’t to that in the build below but you can see an effective star ground snake to ensure currents in the filters don’t migrate into the ground.

3C. Crimp pcb terminals. Or if a hi end look is preferred brass spade terminals or a direct through hole terminals to the exterior of the enclosure and row of internal lock tight binding posts for internal connections.


This was a conventional network for JBL 4344mk2 clone build in Europe.

[VinylGroove]

On the 4343 l recall it was discussed but l don’t have the official updated parts list or any updates to the pcb.

I attached the above 4315 schematics for illustration purposes to identify the parts l referred to in my post. For an equivalent network those parts in the 4315 are required. They are after the L pads and ensures the network functions correctly when connected to the actual loudspeaker drivers.

Feedback and Recommendations.

1. I would also suggest a pcb revision so the cabling for the drivers coming from the pcb and not the L pad tab 1 and tab 2.

2. Secondly, l would recommend the pcbs be provided with quality pre soldered crimp style tab terminals and a labeled crimp connector cable loom for connection to the L pads and from the pcb to the mid, horn and 2405 drivers.

That way testing and disconnection of the pcb and the L pads is much easier for the constructor. Alternatively screw type terminals with spade terminals. It needs to be idiot proof so that incorrect connections by the constructor are eliminated. Labelling of supplied cables with a label maker would make it much for the constructor during installation of the crossover.

You don’t want to be looking back and forth to the instructions when installing the crossover, the cabling and the L pads.

This would make it much simpler for the constructor to wire up the L pads and connect the drivers to the pcb using quality crimp connectors (if my understanding of pcb is correct).

3A. Thirdly, on the size of the pcb to fit inside of the enclosures the final equivalent 4344 networks were assembled with the horn and uhf filters stacked above the mid filter board on nylon stand offs. It might not look as pretty but it’s a better approach. The two split pcbs could still be used for an external crossover network. The point is the constructor is not mandated into an external crossover implementation which will not suit all situations.

3B. For illustration in attached image is a HF & UHF filter boards below where l used nylon spacers with brass M5 screw threads as l recall. The mid filter board was mounted on top. Some cable strain relief ensures the integrity of all cable connections to the board.
More of an option but the pcb could be set up for bi or tri wiring back to the power amp. I didn’t to that in the build below but you can see an effective star ground snake to ensure currents in the filters don’t migrate into the ground.


This was a conventional network for JBL 4344mk2 clone build in Europe.


I never thought of using Wago lever nuts for point to point wiring projects, that's a great idea.

These inline units could be handy as well and would work anywhere there is a wire, regardless of layout. This specific one works with 12-20awg wire.
https://www.amazon.com/221-2401-WAGO-Lever-Nuts%C2%AE-2-Conductor-Transparent/dp/B0BKR2SR7H/

[Ian Mackenzie]

Correct.

They are excellent for loudspeaker wiring

[Ian Mackenzie]

Feedback

No 4. On L pads where JBL specified 16 ohm version this was done for power handling according to JBL’s Mark Gander when asked by Giskard back in 1978.

In these 4315 and 4343 lower sensitivity systems the mid and hf drivers are attenuated more by the L pads than the higher sensitivity systems like the 4345.

For example the 4343 foilcal has 4 db of attenuation for the zero position. If the user dials back the mid range L pad another 2 db that’s a total of 6 db attenuation. So if the mid range driver was getting 50 watts with the L pad up full and you dialled back L pad to -2 db only -13.5 watts would be going to the midrange driver. The L pad would be dissipating 37.5 watts.

Internally a loudspeaker L pad is not a simple potentiometer voltage divider. There are two separate nichrome wire element tracks for a constant impedance attenuator.

In a 16 ohm attenuator the series element track is 16 ohms and the parallel element track is 130 ohms.

An 8 ohm attenuator has an 8 ohm series element and a 32 ohm parallel track.

So for the same level of attention the demands on an 8 ohm L pad are higher with the lower resistance values.

This is because the lower resistance tracks in the 8 ohm L pad create a larger voltage drop across the element tracks where the load impedance is 8 ohms. Power dissipation = V 2 / R where V is the voltage drop and R is the resistance.

Therefore it is not recommended to amend the L pad values in equivalent networks. Watching your new crossover network smoking at the peak of party and then fail is not good optics. In addition the existing L pads can be utilised for internal pcb installation.