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Dr.db
01-11-2016, 05:41 PM
Hello,

is it possible to change the alluminum diaphragm in the 2441 driver with the TRUEXTENT beryllium dia´s without changing the 3155 crossover?

As the 2405 covers all frequencies above 10khz, is their any real benefit in the beryllium diaphragms anyway?
I don`t need extended freq-response, so is it worth it ?
Is beryllium that much superior to the alluminum D16R2441 diaphragms ?


Thanks a lot,
Olaf

Challenger604
01-11-2016, 05:43 PM
Hello,

is it possible to change the alluminum diaphragm in the 2441 driver with the TRUEXTENT beryllium dia´s without changing the 3155 crossover?

As the 2405 covers all frequencies above 10khz, is their any real benefit in the beryllium diaphragms anyway?
I don`t need extended freq-response, so is it worth it ?
Is beryllium that much superior to the alluminum D16R2441 diaphragms ?


Thanks a lot,
Olaf

The aluminum diaphragm is what you want! Don't change anything!
C

1audiohack
01-11-2016, 10:19 PM
I went down this road with my 4350's. I loaded a second pair of 2440's with TruExtent diaphragms and loaded them in the cabinets with another pair of 2405's. I honestly could not hear the difference swtching side to side. I left them fully loaded for a couple of months and finally took them out.

In a better horn they are an audible improvement to me but in the 2311/2308 they are not discernibly different.

Barry.

Mannermusic
01-12-2016, 06:36 AM
I went down this road with my 4350's. I loaded a second pair of 2440's with TruExtent diaphragms and loaded them in the cabinets with another pair of 2405's. I honestly could not hear the difference swtching side to side. I left them fully loaded for a couple of months and finally took them out.

In a better horn they are an audible improvement to me but in the 2311/2308 they are not discernibly different.

Barry.

From local JBL pro re blind-fold A-B: "Yes, they are better, but the difference is extremely subtle. Thing is, there are many things you can do with your system to improve performance more. Once you get everything else perfected, this might be a consideration . . . but it is certainly is NOT worth the money." He recommends the 2441. Mike

Challenger604
01-12-2016, 07:42 AM
Hello,

is it possible to change the alluminum diaphragm in the 2441 driver with the TRUEXTENT beryllium dia´s without changing the 3155 crossover?

As the 2405 covers all frequencies above 10khz, is their any real benefit in the beryllium diaphragms anyway?
I don`t need extended freq-response, so is it worth it ?
Is beryllium that much superior to the alluminum D16R2441 diaphragms ?


Thanks a lot,
Olaf

What I would do though, is to update your crossover. I'm not a fan of coupled at all but it's up to you!
C

Mannermusic
01-12-2016, 09:43 AM
What I would do though, is to update your crossover. I'm not a fan of coupled at all but it's up to you!
C

Yep. I purposely built my 3155 in non-cc configuration, fully intending to "upgrade" and then report the results (One test is worth 1000 expert opinions). Thing is, it sounds good enough that I largely lost interest in the test! Higher priorities. Kind of like the Be diaphragm thing (post #4 above).

speakerdave
01-12-2016, 10:06 AM
Hmm. I experimented with beryllium and aquaplas dusted diaphragms for the treble in my 4345's, which uses the horn for basically the same frequency range as the 4350/55. One thing I never got around to trying was new aluminum diaphragms. I heard improvement with both the things I tried. However these were not controlled experiments because there were other changed factors. That is the beryllium was in TAD 2001's and the dusted diaphragm was in the JBL 2450. I was messing around with this because I wasn't liking the tizzy tizzy I was getting from the treble. When I turned the horn down enough to make it tolerable the image, which was never very well defined in the 4345, had disappeared into the speakers. This problem went away with both of the alternate drivers. The larger diaphragm in the 2450 probably inherently has less distortion, and of course both alternate drivers have different phase plugs. Still, I think the relevant factors are something else. First, the mass break point for both titanium, the material in the dusted diaphragm, and aluminum are within the relevant range. That of beryllium is outside it (above). The aquaplas dusting dampens the rattle in the material, but it adds mass. The beryllium is not only not rattling, but it is also lighter than the other materials, so it will follow the waveform of the signal more accurately. This is an advantage over the whole frequency range. HF extension is a secondary benefit. The irritation of the tizziness was gone with both materials, but the beryllium had the added benefit of greater accuracy as well. The audible effect was what some listeners call greater inner detail, which opens up the music considerably, especially with complex sound such as orchestral music. I wouldn't characterize the differences I was hearing as extremely subtle. They were quite evident and identifiable.

Anyway, that's my theory. I settled on the beryllium.

Ian Mackenzie
01-12-2016, 11:38 PM
I did some experiements on the 4345 also.

I had similar finding with the dusted titanium 2425 over the non non dusted 2425.

I preferred however the overall presentation of the non dusted 2425 with the stock 3145 network. It seemed to voice more coherently.

The Tad 2002 however voiced correctly in the stock 4345 network.

The horn is tightly controlled in the passband so the Tad is just doing a better job.

I agree the dusted driver lacks some spatial dynamics and can sound recessed compared to the agressive sparkle of the non dusted driver. Its kind of mellow.

I put this down to the Tad being a more refined driver than the 2425.

In the 4344mk11 network the dusted driver is setup up to run almost full range and the 2405 voltage drive is different. The transition is blended well. The voicing with the dusted driver is spot on.

So l think the system needs to be voiced accordingly to get the optimal results with dusted drivers.

This all goes back to Floyds subjective listening and subjective measurement theory. Greg and his team were ahead of their time in the way they were able to emperically voice these amazing heritage systems.

The business effectively ended an era with a self inflicted orbital lobotomy when they sacked Greg.

speakerdave
01-13-2016, 12:22 AM
I'm glad you mentioned the stock 4345 network, because it might be important. Some of us involved with these experiments wondered why we were getting away with substituting an 8 ohm TAD for a 16 ohm JBL and thought it might have been the tapped inductor in the treble shelving circuit. Just a guess, I would say. Of course, that is not present in the DIY versions.

4313B
01-13-2016, 06:52 AM
DIY M2

Seriously...

Send that stuff to Japan, get a bag of gold for it and pick up the M2 components. ;)

4313B
01-13-2016, 07:10 AM
What I would do though, is to update your crossover. I'm not a fan of coupled at all but it's up to you!
CThere is nothing to be a fan about. As both Ed Meitner and Greg Timbers have maintained, it is a valid topology. I am aware of the fact that there are numerous people against the practice but nobody that matters cares. We are talking about guys that use a notch above state of the art gear that costs tens of thousands of dollars. :o:

It is like the Be diaphragms, simply put, most folks systems and hearing won't be able to take advantage of the increased performance. The truth is that the Be diaphragms are a SIGNIFICANT improvement over any other material, including Mg. If a person can't hear the difference then YEE HAW! They just saved a bunch of money arguably better spent on beer. :)

4313B
01-13-2016, 07:27 AM
Hello,

is it possible to change the alluminum diaphragm in the 2441 driver with the TRUEXTENT beryllium dia´s without changing the 3155 crossover?

As the 2405 covers all frequencies above 10khz, is their any real benefit in the beryllium diaphragms anyway?
I don`t need extended freq-response, so is it worth it ?
Is beryllium that much superior to the alluminum D16R2441 diaphragms ?


Thanks a lot,
OlafAt this point in time I would just leave these legacy systems as they were originally designed. If they no longer do what you want them to do then move on.

4313B
01-13-2016, 07:58 AM
I agree the dusted driver lacks some spatial dynamics and can sound recessed compared to the agressive sparkle of the non dusted driver. Its kind of mellow.Another one of G.T.'s neat ideas based on his R&D.

With the D2430K at the ridiculously low price it is, dusting legacy diaphragms is a thing of the past. :) It does not have the ultra low distortion that the Be has but there is something about it that sounds really nice. Yes, I am aware of some people not liking it - user error - enough said. It is a very capable transducer and it is very inexpensive.

Dr.db
01-13-2016, 08:35 AM
Thanks all for your replies, very appreciated! :)




Hello,

is it possible to change the alluminum diaphragm in the 2441 driver with the TRUEXTENT beryllium dia´s without changing the 3155 crossover?

Thanks a lot,
Olaf


At this point in time I would just leave these legacy systems as they were originally designed. If they no longer do what you want them to do then move on.

Would there have to be any changes to the 3155 crossover when using the Truextent dia´s in your opinion ?

JeffW
01-13-2016, 09:48 AM
One thing that I've never seen addressed is the polarity of the TruExtent. They sell the same diaphragms to fit many different drivers, even different brands. But some of those drivers - even within the brand in JBL's case - have different polarity. Probably only matters with drivers already installed in a system, a raw driver could just be hooked up red to + and confirmed with measurement. But what about swapping a -SL diaphragm from a 2450SL (negative polarity/red to -) into a 2452 (positive polarity/red to +) or replacing the stock diaphragm in a 2450SL/2451/2452 with a TruExtent? The 2440 pdf (http://www.jblpro.com/pub/obsolete/2440.pdf) doesn't mention which way the 2440 is wired.

I didn't see the list of drivers supported on the TruExtent website any more, but OCS is showing them (http://www.speakerrepair.com/page/product/Truextent-Diaphragms/BeX4008.html) to drop in fit the negative polarity drivers, as well as 2440 and 2441.

Anyway, just something to consider when swapping diaphragms.

ivica
01-13-2016, 10:25 AM
Thanks all for your replies, very appreciated! :)

Would there have to be any changes to the 3155 crossover when using the Truextent dia´s in your opinion ?

Hi Dr.db,

As Be (Truextent) is said that it has several +dB in the mid-range region (as shown in the paper) over JBL Ti and Ti-SL, I would expect that some additional tweaking of the original 3155 network would be well-come.

Regards
ivica

4313B
01-13-2016, 12:20 PM
Would there have to be any changes to the 3155 crossover when using the Truextent dia´s in your opinion ?G.T. would very probably say yes, he never seemed to be a proponent of swapping transducers and networks willy nilly.

I have come to the conclusion that, like all this stuff, it will be just fine for some folks and not so fine for other folks.

Challenger604
01-13-2016, 03:59 PM
There is nothing to be a fan about. As both Ed Meitner and Greg Timbers have maintained, it is a valid topology. I am aware of the fact that there are numerous people against the practice but nobody that matters cares. We are talking about guys that use a notch above state of the art gear that costs tens of thousands of dollars. :o:

It is like the Be diaphragms, simply put, most folks systems and hearing won't be able to take advantage of the increased performance. The truth is that the Be diaphragms are a SIGNIFICANT improvement over any other material, including Mg. If a person can't hear the difference then YEE HAW! They just saved a bunch of money arguably better spent on beer. :)

4313B? Do we speak about the same language? I heard the diffrence! Coupled and mine! Guess what??

4313B
01-14-2016, 12:39 PM
4313B? Do we speak about the same language? I heard the diffrence! Coupled and mine! Guess what??There is no need for me to guess, the charge-coupled networks are better. :) If you think otherwise then you are wrong. Period. There is no "opinion" involved in this and I won't play that little game of being polite about it. To be blunt, there is no way in hell on earth JBL is going to waste one cent on biasing networks in their top of the line systems if there isn't an advantage in doing so. I will, however, concede that it is entirely possible that the 4355 simply doesn't have decent enough components to take advantage of charge-coupled networks. :D If that is the case then that would put their component complement a few steps below the components found in the 4406, the smallest system I have biased.

Odd
01-14-2016, 12:51 PM
Yes it is quite clear that charge-coupled networks sounds better.

Challenger604
01-14-2016, 03:01 PM
Yes it is quite clear that charge-coupled networks sounds better.

Hi Odd,
I respectfully desagree.

Happy New Year to you.
C

Odd
01-15-2016, 02:44 AM
Hi Odd,
I respectfully desagree.

Happy New Year to you.
C


Happy New Year!

You have to build new crossover this year.
Then we would agree.

Challenger604
01-15-2016, 09:07 AM
Happy New Year!

You have to build new crossover this year.
Then we would agree.


Thanks Odd!
Oh no! My 4355's sound so good I won't change for nothing!
Coupled crossover is like global warming! A huge scam!!
Sorry! This is my own opinion with few...
C

sebackman
01-15-2016, 09:13 AM
I'm lazy when swapping diaphragms. I check polarity by applying 1,5v from a AAA battery to the diaphragm when mounted in the driver and the acoustical negative pole is the pole where applying + from the battery moves the diaphragm out from the phase plug. I prefer to apply voltage so it moves the diaphragm out from the phase plug but if you get it the other way around it inflicts no harm with such low voltage. I have never had a diaphragm touching the phase plug by doing this simple test.

If the terminals are different between different driver motors, just turn the diaphragm180 degrees to get the terminal cables right.

It does not move much but it is clearly visible to the eye with a good flash light.

Don’t forget to sweep with a tone generator to be certain that there are no resonances after mounting. There should not be any rattle with these drivers but I find that sometimes there is anyway…

I agree with what is said above regarding Be contra other dome materials but would like to add that the Be rolls off earlier than an SL (coated) diaphragm which will demand more EQ to go “all the way”.

The SL is easier (less EQ) to extend above 12k (if desired) and may prove a good alternative when going for a 2-way solution or when the 077 cuts in very high.

JBL solved the Be roll off to some extent by introducing 045 tweeter in the K2 models and the newer 43xx’s.

To my ears the SL sound more musical than Alu and Ti, albeit it may not do so in a system designed for Ti or Alu diaphrams from the outset as mentioned above. I would not know as I only run active DIY designs.

The difference between SL and Be is clearly audible but I would prefer a 2-way SL system before a more complex Be 3-way if I started from scratch. I’m right now building both alternatives with M2 waveguides and the reason is that I had all the components. If I had nothing to start with I would go 2430k as 4313b points out above, albeit the 4”drivers looks like they sound way much better J .

And of course, my diaphragm discussion here is completely useless and irrelevant to all 4-way 43xx owners as they already do have a UHF/077/2405 unit built in. J

Kind regards
//RoB

4313B
01-15-2016, 09:30 AM
Coupled crossover is like global warming! A huge scam!!Another idiot on the waiting list for a brain donor...

Ian Mackenzie
01-15-2016, 09:39 AM
CC is a means to an end. The most recent implementation is really neat with self powering the Dc bias from the signal.

In many circuits a capacitor blocks Dc from entering the signal so the re e is nothing unique going on here.

When the Ac voltage is not constant but is pulsed and frequency modulated the dielectric (foil) can rattle depending on how the capacitor is wound. The rattling results in non linear behavior of the dielectric. Applying the DC bias adds tension to the film/foil construction of the dielectric and minimize the rattling.

Some capacitor are wound are made in such a way that the dielectric will not rattle (stacked foil) or has damping like Oil . This can be an expensive manufacturer process.

With JBL it's alwsys been about the drivers so its nice to see the impact of the capacitor being removed from the equation.

I am not sure if the Greens would like it with twice the values and quantity of parts.

Ian Mackenzie
01-15-2016, 10:53 AM
Back OT if you can find diamond aluminum diaphragms l am sure you will be quite happy. Also consider a Westlake or Smith horn atop the 4355. Going Be is an expensive exercise and unless with rest of the food chain is pristine you may hear more about the rest of your system than what is on the record.

Beyond that its real tweeker journey. Most don't really see the impact of a series inductor. Inductors are the evil curse of passive crossovers.

If you made the 12 inch midcone fully active with the correct voltage drive the performance would elevate to a new level . Get the midrange right and you stop worrying about everything else. I am thinking about getting another B4 First Watt active crossover and going 3 way active with my 4345s.

Challenger604
01-15-2016, 03:37 PM
Another idiot on the waiting list for a brain donor...

Why the direct insult?
Incapable to argue?

Prove to me that it's better? Did you hear two pairs of 4355's with differents xover same amps? Did you EVER heard just one pair? Have you seen a pair?? So until you do! Keep your insults in your mouth!

pos
01-15-2016, 03:48 PM
Well, Challenger604, calling other people's work a scam *is* an insult
(and beside that, considering that global warming is a scam is... kind of stupid)

BMWCCA
01-15-2016, 03:49 PM
Did you EVER hear just one pair? Have you seen a pair??
Now children . . . we're all friends here, right?

Not defending the tone but I believe 4313b created the circuitry design for the CC network I'm using in my 4345, and I'm quite certain he's heard more 43xx versions than many if not all of us here. And built quite a few, too.

I guess the same question you asked could be asked of you, since you made the first of the damning declarations. :dont-know:

Challenger604
01-15-2016, 05:33 PM
Well, Challenger604, calling other people's work a scam *is* an insult
(and beside that, considering that global warming is a scam is... kind of stupid)

I said! Global Warming is a scam as coupled xover! I didn't say that he was a brainless moron!!

Challenger604
01-15-2016, 05:36 PM
Now children . . . we're all friends here, right?

Not defending the tone but I believe 4313b created the circuitry design for the CC network I'm using in my 4345, and I'm quite certain he's heard more 43xx versions than many if not all of us here. And built quite a few, too.

I guess the same question you asked could be asked of you, since you made the first of the damning declarations. :dont-know:

So! If he was so educated, why does he react the way he does?? Humilty? Wisdom? Anyway! No matter what you would say! Some will still believe in global warming!

Ian Mackenzie
01-15-2016, 07:09 PM
When the CC network is in place if the battery is removed the difference is quite audible once the capacitor has discharged.

The CC does improve sound quality with the Solen fast capacitors as specified. This is a fact from controlled listening test in my audio laboratory.

I am not going to elaborate subjectively other than the CC when 'on' made a noticable improvement to all members of listening panel.
The consensus at the time was CC was a brilliant idea and delivered the results without resorting to prohibitively expensive parts in a commercial loudspeaker.

At the time we compared networks with mylar , bypassed mylar, polypropolyne, bypassed polypropolyne, exotic silver and oil Munforf capacitors with charge coupled Solen fast caps.

The wider consideration is that Solen makes some high quality range capacitor like teflon. I am not aware of any CC testing with Teflon capacitor but it would be hideously expensive.

Challenger604
01-15-2016, 07:17 PM
When the CC network is in place if the battery is removed the difference is quite audible once the capacitor has discharged.

The CC does improve sound quality with the Solen fast capacitors as specified. This us a fact.

The wider consideration is that Solen makes some high quality range capacitor like teflon. I am not aware oc any CC testing with Teflon capacitor but it would be hideously expensive.

Everything on my crossovers are from Solen! Top notch!
Everything on his coupled crossovers are from Solen! Top notch!
And! A huge difference between the two! Obvious! Shocking!

Ian Mackenzie
01-15-2016, 07:41 PM
Unless you can substantiate you comment you are merely stating an opinion . There are thousands if not million of opinions of audio. Most of them are wrong and at best misleading as there is not science to support the opinion.

My original post was based on work over a 12 month period.

Your opinion only took 30 seconds to write.

Challenger604
01-15-2016, 07:57 PM
Unless you can substantiate you comment you are merely stating an opinion . There are thousands if not million of opinions of audio. Most of them are wrong and at best misleading as there is not science to support the opinion.

My original post was based on work over a 12 month period.

Your opinion only took 30 seconds to write.

Based longer than that with one of the best former JBL engineer in Montreal... I'm just a former sound engineer...

Ian Mackenzie
01-15-2016, 08:56 PM
That tells me you are most likely have permanent hearing damage.

I am not convinced being a sound engineer (an authority on recorded music, public address system) serves to support the validity of your post. If said you were a research fellow at a university or has a phd on acoustics and had been collecting evidence to confirm a fact l might believe you.

I hope you dont think l an being a prick, a PITA yes.

I never said CC was the only solution.

If someone says they have a better solution give me some real proof

sebackman
01-16-2016, 02:42 AM
No need for a battle of proof here boys.

Our joint interest for audio is our hobby, at least for most of us. Our personal background or experience does not preclude anyone of us to enjoy their system of taste and to share their findings here on the forum.

This forum is not the world championship in audio, it’s here to help all of us to take our hobby one step forward by sharing knowledge and experiences. We need to always bear in mind that such step can be in different directions for different people.

Some of the members have fantastic knowledge and can bring enormous amounts of experience to the rest of us on the forum. That is why we are here.

We owe gratitude to the senior members that share their insight and happily take their time to answers our, sometimes very basic or stupid, questions on the forum. Some of the members like 4313b and others have access to information the rest of us otherwise cannot get, it is invaluable for us and our hobby. The forum is a wonderful source for discussion and information that each person can choose to embrace or not. -Nothing short of brilliant.

There is little doubt that 30-40 years of development have brought new materials, technology and solutions to the audio industry and that new technology can improve on older constructions. However we must keep in mind that “improvement” does not mean the same thing to all of us. If someone loves the sound of a certain older design it is fantastic, let them enjoy their system anyway they can.

Can older designs be sonically improved by applying the knowledge and yard stick of today? Yes in many ways, both regarding design and components. Does that mean that the listener will be happier? Not necessarily. :dont-know:

It must be allowed to have different opinions on perceived sound quality even if technology or measurements say otherwise. We cannot predict the function and integration of all possible combination of speakers, filters, rooms and peoples taste.
Some improvements can be clearly verified by listening, others by measurements, but even verified improvements does not mean that they are to the liking of all listeners. The only thing that matters is the taste and perceived sound quality of each listener. It is not a matter of what system or technology is objectively best but rather what each members subjectively likes the most.


There is no doubt to me that CC networks do have a sonically advantage over conventional networks in most systems (if not all), but it does not mean that my ears and my taste will confirm that my system in my environment is perceived improved by swapping XO topology. I like the 4" drivers better than the 3" drivers but I have no real reason to do so. - But I do anyway. :blink: However, on a general note I must say that it is very likely that newer technology is "objectively better", unless it is introduced just to be cheaper or more profitable for Harman (good enough...).

Hearing impairment or not. :)

If everyone would run M2’s and share the exact opinion of them and the technology behind, then it would be a rather dull world.

Much of little.

Have a nice weekend

//RoB

Challenger604
01-16-2016, 05:45 AM
That tells me you are most likely have permanent hearing damage.

I am not convinced being a sound engineer (an authority on recorded music, public address system) serves to support the validity of your post. If said you were a research fellow at a university or has a phd on acoustics and had been collecting evidence to confirm a fact l might believe you.

I hope you dont think l an being a prick, a PITA yes.

I never said CC was the only solution.

If someone says they have a better solution give me some real proof

I was in the movie industry for 15 years. Still have a perfect hearing. Checked in regular basis... (Aviation medical requirement).

4313B
01-16-2016, 12:46 PM
Incapable to argue?Your two statements proved beyond question that there is nothing at all to argue about. I have zero tolerance for willful ignorance. To be blunt, I was completely taken aback by them.



I have yet to hear of ANYONE removing the charge-coupled networks from their SOTA JBL loudspeaker systems and replacing them with non-biased versions.
Same goes for the Be diaphragms. I have not heard of a single instance of someone changing out their Be diaphragms for aluminum, titanium, or magnesium.
JBL isn't making 4355's, they are making charge-coupled K2's, Everest II's, and 4365's/4367's.

Challenger604
01-16-2016, 02:03 PM
Your two statements proved beyond question that there is nothing at all to argue about. I have zero tolerance for willful ignorance. To be blunt, I was completely taken aback by them.



I have yet to hear of ANYONE removing the charge-coupled networks from their SOTA JBL loudspeaker systems and replacing them with non-biased versions.
Same goes for the Be diaphragms. I have not heard of a single instance of someone changing out their Be diaphragms for aluminum, titanium, or magnesium.
JBL isn't making 4355's, they are making charge-coupled K2's, Everest II's, and 4365's/4367's.

Coupled crossover is garbage! I'm sure made in China!

pos
01-16-2016, 02:17 PM
At that point you are only trolling, this is getting ridiculous...

Mr. Widget
01-16-2016, 02:23 PM
At that point you are only trolling, this is getting ridiculous...+1


Widget

Ian Mackenzie
01-16-2016, 03:08 PM
Although this link to another thread is not specifically about Be it does refer to members upgrades of legacy systems ans is quite informative.

I find couch / potato posts far less useful than from those with some practical activity.

http://www.audioheritage.org/vbulletin/showthread.php?6633-Discussion-Thread-JBL-4343-to-4344-upgrade/page20&highlight=

Dr.db
01-16-2016, 03:44 PM
Back OT if you can find diamond aluminum diaphragms l am sure you will be quite happy. Also consider a Westlake or Smith horn atop the 4355. Going Be is an expensive exercise and unless with rest of the food chain is pristine you may hear more about the rest of your system than what is on the record.

Beyond that its real tweeker journey. Most don't really see the impact of a series inductor. Inductors are the evil curse of passive crossovers.

If you made the 12 inch midcone fully active with the correct voltage drive the performance would elevate to a new level . Get the midrange right and you stop worrying about everything else. I am thinking about getting another B4 First Watt active crossover and going 3 way active with my 4345s.


Thanks for your advise! :)
What is the main problem with series inductors?

Ian Mackenzie
01-16-2016, 03:50 PM
This is an interesting thread on Charge Coupling.

I cant believe how passionate l was about all this stuff back then.

At the moment l have my hands full (literally) so posting is only here and there.

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

Ian Mackenzie
01-16-2016, 04:25 PM
I dont like series inductors in the signal path .

I physical inductor is never an ideal passive component, they have insertion losses, other properties that can impart impurities in the signal and their intended effect is never optimal as the loudspeaker is an electro mechanical device that reacts with the inductor.

When an inductor sees a driver and its motional impediance the perfect world of your crossover schematic turns to hell.

The crossover is usually design around small signal performance of the driver. Ramp up the power and everything shifts and is sometimes modulated with thermal distortion.

Simple aspects like dynamic damping also go to hell.

Bi amping bypasses all of this and yhe crossover function is independent of the driver influence and is under the driect control of the amplifier. Stuff like Thd of the driver will still rise with increased power but all the driver parameters the passive crossovers rely on are effectively de coupled from the crossover with full bi amping.


At realistic volume levels the mid bass driver actually moves and we want it to work almost ideally to create the the reverberant ambiance of the original musical event. Most commercial loudspeakers compromise this and no one cares because the loudspeaker can cant go loud enough anyway. But in the case of ghe 4355 the diyer has the opportunity to push the envelope.

Dr.db
01-16-2016, 08:24 PM
But if I didn`t get you wrong, the mid and high horndrivers still remain with their inductors, right ?
So the mentioned problems would be still an issue in that range...