JBL D2430K Available

[alskinner]

I confirmed with Melissa at Speaker Exchange that the JBL D2430K is back in stock if any one is looking for them. I ordered two for $767.68 which includes shipping.

Regards
Al

[alskinner]

Drivers arrived yesterday. Only took two days to receive them.

Regards

AL

[Mr. Widget]

Looks like Christmas!


Widget

[withTarragon]

Al, Congratulations on getting the drivers. Many years ago, the "version" of the driver meant for use specific use in the M2, would have a sticker on the side that said something to the effect "for use on the M2". I got mine a couple of years ago and when I ordered the vendor double checked and assured me they were for use with the M2, but there was no "M2" sticker on the side. There are various theories on why the M2 sticker was added ...... many of these theories are about a decade old.Quick question, do your drivers have the "M2" sticker on the side?Thanks, -Tom

[alskinner]

Hi

No they don't have a M2 sticker on the side. However, according to the part number 5032754X on the box it is correct for the M2. Hope that helps.

Regards

AL

[alskinner]

Tom,

Attached are pictures of the box which does state M2 on it

Regards
AL

[rusty jefferson]

Congratulations on picking up those drivers. I have not yet heard an M2 system but did listen to these on a pair of 4367s and thought they were excellent. Are you making a clone of one of those monitors?

[alskinner]

I'm not sure yet but leaning towards the 4367 mainly because of the passive network The problem will probably be finding the horn for sale for it.

The M2 is dsp controlled and building a decent passive network for it will be difficult for me but, the horn for the M2 is available. I'd love to build a true M2 clone but the electronics cost is prohibitive for me. It may be possible to modify the 4367 network to use with the M2 horn.

I've got a lot of research to do while building my skills to accurately measure the speakers response.

Any guidance or suggestions are always welcome.

Thanks
AL

[pos]

The M2 is dsp controlled and building a decent passive network for it will be difficult for me but, the horn for the M2 is available. I'd love to build a true M2 clone but the electronics cost is prohibitive for me. It may be possible to modify the 4367 network to use with the M2 horn.It depends on what you call expensive, but you can probably replicate the original filtering closely enough using hypex fusion amps.

[alskinner]

Thanks POS

According to the M2 system requirements for either two Crown I-Tech 5000HD at $7,043.96 each or one I-Tech 4x3500HD at $14,496.54 for a true clone. A little too expensive for me. I appreciate your suggestion and will definitely
look into the hypex fusion amps.

Thanks
AL

[rusty jefferson]

I'll throw this idea out since you're not sure yet. If you're not familiar with Joseph Crowe, he designs and builds wood horns in Canada. He also sells CAD files for his horns to allow diyers to 3D print the horns, or have them CNC cut locally. If money is tight, you could probably get a pair of these 3D printed locally for a few hundred dollars. Another member here recently did this with one of his 1" horns and they turned out good and measured well. Of course, if within your budget he could make you the wood horns...

https://josephcrowe.com/products/3d-cad-plans-for-es-290-biradial-horn-horn-no-1670

[pos]

According to the M2 system requirements for either two Crown I-Tech 5000HD at $7,043.96 each or one I-Tech 4x3500HD at $14,496.54 for a true clone.There are several other proven options available if you are ok to separate the amps and processors: BSS BLU, openDRC, DCX2496, etc.

[alskinner]

I appreciate all your support. It has given me a lot to think about. I do have several amps. It will probably be a while before I actually build a system. I have the 2216s but still need the horns and adapters. My main goal right now is to get the parts before they are no longer available.

Right now I'm building a test stand for my 2441s and 2311 horns to see if it's worth while to integrate them in the 4344s. The shorter horns will better line up the 2235 and 2122 magnets and help remove the delay of using 2307 horn. It will be interesting to hear the difference.

Another project that is in the works is a DD55000 clone. I have pair of NOS E145s, 077s, and 2425hs but only have one 4660 horn. Not sure when and if I will find another one.

Regards
AL

[alskinner]

Attached are some pictures of the variation of the M2 I came up with. The cabinet is 46.5" H x 19.5" W x 13" D. Internal dimensions are 45"H x 18.25"W x 11.5"D which comes out to 5.46 cubic feet. I believe the M2 has an internal measurement of around 5.2 cubic feet. I did use 2" x 3 " internal bracing so that would bring down the cubic feet slightly. I used 3" Precision ports with a 8.4" length for a tuning frequency of 27hz. There is a 3/4" thick panel around the port area. I know some people curved it but I thought I would try it straight to see what the effect would be. The grill is a solid piece of 3/4 inch plywood with a 16.75" hole cut so that it fits over the woofer. This will also change the way the woofer acts and I'll need to take measurements to see what the effect it has. It also has the M2 crossover.

I bought I MiniDSP 2x4HD and hooked it up to a Threshold Stasis II and a Sunn SPL 9000 amp and made some basic xovers to get sound and not blow anything up. I now have a rudimentary understanding of how the DSP works so now the fun begins as I have a lot to learn and the ability to measure it is crucial to success. Will post more as the project progresses.

If this needs to be moved to a different area of the forum please do.

Regards
AL

[Mr. Widget]

Cool!

I think you might want to consider the miniDSP Flex unit to take care of your needs. By all reports the version with Dirac Live is technically excellent. I bought a variant that I use as an A to D for an all digital system and am impressed with the quality. Not sure about the interface and learning curve on adjusting the settings as I haven't needed to dig into that level, but many other DIYers have had great success so you should be fine.

With the Flex version you should be able to take the info POS has posted on the M2 curves and get these dialed in to perfection and can use Dirac Live to correct any room issues. I believe the 2X4HD will only give you basic crossover functionality.


Widget

[alskinner]

Thanks Widget

I bought the 2x4hd as a learning tool and as I reach the limits of it's capability plan to upgrade to either a BSS or the Flex. Being able to import the M2 files would defiantly save a bunch of time and frustration, but even those files may need to be tweaked due to my cabinet design. This is my first foray into DSP so I have got a lot to learn. I do have patience as it took me years to get the 4344s to sound like I wanted them to.

I also want to get new amplification as what I have is at least 30 years old. Although the Threshold has been a reliable workhorse there is better technology out there. I'm leaning toward Parasound right now

[sebackman]

Nice work. Enjoy, they are fantastic but may require some attention to the room as they are 100 by 100 in coverage.

Let the fun begin!

[withTarragon]

Cool!I think you might want to consider the miniDSP Flex unit to take care of your needs. By all reports the version with Dirac Live is technically excellent. I bought a variant that I use as an A to D for an all digital system and am impressed with the quality. Not sure about the interface and learning curve on adjusting the settings as I haven't needed to dig into that level, but many other DIYers have had great success so you should be fine.With the Flex version you should be able to take the info POS has posted on the M2 curves and get these dialed in to perfection and can use Dirac Live to correct any room issues. I believe the 2X4HD will only give you basic crossover functionality.WidgetThe Flex unit is an exciting offering. Do you know, or does anyone else know, whether "both sets" of coefficients from POS will work on the Flex unit. The first set is IIR coefficients of standard filters and their associated phase shifts. There is also did a second set using FIR filters which can "undo" the phase shifts (IOW, a flatter phase spectrum) but with a penalty of increased computational resources. When POS did this using using OpenDRC-DI (which has both IIR and FIR filers), then TWO units were required due to the increased computational load. My question is whether a SINGLE Flex unit (which can do both IIR and FIR filters) has sufficient horsepower to do all four output filters using FIR filtering. If the answer is complicated, then I can start a fresh thread and not corrupt this one.

[Mr. Widget]

I have not used any of the miniDSP Flex's features beyond using it as a simple A to D so I haven't researched the capabilities and limitations. In comparison with the BSS offerings, it is a more modern design than the BSS units I am familiar with so it may offer higher performance... which may or may not be audible.


Widget

[Robh3606]

They look really good! Have fun, curious what your comparison will be to the 4344's. I really like mine and the 100 X 100 works just fine for me.

Rob :)

[alskinner]

Thanks Rob

I suspect that the m2 will be more refined and accurate, but the 4344s will beat them in pure dynamics. Only time will tell. I ended up with a 2441 on a 2311 horn, that combination suited me best, they sound great with little equalization needed.

Al

[Ian Mackenzie]

Don’t be afraid to go off the reservation and look at at a slight EQ above 2 khertz at 1.5 db per octave. Greg Timber’s suggested this when l designed a passive crossover/ EQ for the M2 horn. Looking at Mitchco’s video tutorials and the Harman curves it make sense…..

Enjoy

Ian

[jmpsmash]

I'm not sure yet but leaning towards the 4367 mainly because of the passive network The problem will probably be finding the horn for sale for it. The M2 is dsp controlled and building a decent passive network for it will be difficult for me but, the horn for the M2 is available. I'd love to build a true M2 clone but the electronics cost is prohibitive for me. It may be possible to modify the 4367 network to use with the M2 horn.A bit late in reply, you probably went a different route but I will put it here for reference.I have tried using the 4367 network topology on M2 horn. I didn't replicate the charge coupling, didn't have enough caps around. So I just replaced them with equivalent capacitance.Using the original 4367 network component values won't give you a flat response as is. They don't have the same exact response. It is confirmed from recent comparative measurements from sebackman. But they are pretty close so it is tweakable. When I did it I measured the response of the D2430K+M2 raw, replicated the network topology in Vituixcad and manually adjusted the response flat. It worked well standalone and the shape looks good. However, due to the difference in acoustic center between the 2 horns, phase matching won't work in the crossover region. More work needed to get that to match. I eventually added another order in the woofer network to get them to match.Ultimately, the overall sound was so-so so in the end, I abandoned the project.Looking back, I don't think it will be easier to use the 4367 network on the D2430k+M2 horn as it is not plug and play. Furthermore, if you are starting from scratch it will be cheaper to just do DSP crossover. The network is quite complicated and the cost of all the caps and inductors will likely cost more than a minidsp.

[jmpsmash]

apologies for the formatting in my last post. somehow all the new lines are not showing up.very strange.

[alskinner]

Thanks for the information on the passive crossover. I may try one in the future but the complexity of getting it right will take a lot of time. I think Ian is way ahead in getting the passive to work properly. I did get the crossover and the peq settings installed into the minidsp 2x4HD according to the paper POS(Rob) published. The only thing I have not put in is the Fir rephrase described in the paper as I will need to study the process more to feel comfortable doing it. Although it sounds pretty good the sound is not quite there yet. I still have a lot of work to do with room correction and tweaking the settings for the variation in the cabinet. I also started measuring the response with six studio audio tools as soon as I am comfortable with the measurements I'll post the findings.

Before I go too far I want to get the signal chain like I want it. I have a parasound A21+ coming and if it performs like I think it will I'll order an A23+ for the top end. One thing I discovered if the signal chain is not right it doesn't matter what you do to the speakers they will not sound the best it can.

Thanks for every ones help.


The Journey continues

Al

[Mr. Widget]

apologies for the formatting in my last post. somehow all the new lines are not showing up.very strange.Take a look at this post by Earl. The forum is still broken and Earl found a way to make it less broken: https://www.audioheritage.org/vbulletin/showthread.php?43110-Forum-image-upload-error&p=442784&viewfull=1#post442784


Widget

[jmpsmash]

Take a look at this post by Earl. The forum is still broken and Earl found a way to make it less broken: https://www.audioheritage.org/vbulletin/showthread.php?43110-Forum-image-upload-error&p=442784&viewfull=1#post442784


Widget

Thanks.

I will try it.

(and it works )

[alskinner]

In my previous post I called POS Rob. My apologies for messing up your name. One of those senior moments.

[alskinner]

Attached is an REW graph showing where I am so far.1st graph is the M2 the second graph is the 4344. I still have a lot to learn about measurements but am becoming more comfortable in the basics. Any input would be appreciated. I measured using a MiniDSP umik-1 mic Measurement was 3 foot from the left speaker with the mic 12 inches from the floor and pointed to the middle of the speaker. I have a tripod coming which will help improve my measurements. I am using a MiniDSP Flex. I have a Parasound 21+ for the lower band an a Parasound 23+ for the upper band.

I would like to thank POS for the settings documented in his excellent paper on the JBL M2 crossover. I did use the ACD spreadsheet to construct the biquads for the 36db linkwitz lower crossover based on his recommendation and confirmed with the Linkwitz -Riley website. There were numerous people in the massive M2 threads that were of immense help and I appreciate it.

One thing I learned using Windows 11 is there are all kinds of enhancements that are turned on by default. After turning off the enhancements I started to get readings that made more sense.

Robh asked me for an opinion between the M2 and 4344. IMHO the M2 is more refined with great detail especially percussion reproduction with a well focused sound stage. On the other hand the 4344 with a 2441 and 2311 horn is slightly more exciting with a more in your chest bass and an articulate high end. Voices are well defined. Of course this may change as I finish dialing the M2 in which in my case may take years. I have Dirac capability and as soon as my tripod comes in I will try my hand at room correction.

Regards
Al

[alskinner]

At first I had trouble keeping a connection to the Dirac server due to my ancient computer and operating system. I bought a new one, loaded 32 GB of ram and the connection was steady as a rock.

I then loaded the equalization and crossover settings provided by POS in the output section as Dirac will not allow you to load equalization in the input section in the minidsp. Using a minidsp UMIK-1 mic as recommended by Dirac I proceeded to the volume calibration settings setting the output and mic settings. If these settings are too low Dirac will let you know. I then went to measurement section and chose the 13 position measurements which record data from the front, back and both sides of the listening position. It is important that these measurements are equal for both sides of the measured position and room needs to be as quiet as possible. After that I went to the filter design section where you can accept the preliminary settings or customize them by the use of shelving and/or individual equalizer control points. You can then export the project to a slot on the MiniDsp. These settings can be edited at any time.

Upon playing music using Dirac I noticed a great reduction in room resonances without sacrificing bass response. Instruments and voices had a greater degree of separation with a spatial quality in the music. I verified this by toggling between the regular Flex module and Dirac. Two of the recordings I used was The Who's, Eyesight to the Blind from the album Tommy. Keith Moon's drumming and crash cymbals sounded more life like. The other recording was Pink Floyd's Pigs (three different ones) from the album Animals(2018 remix). The spatial quality was excellent with David Gilmour's guitar more life like. All music sounds better but well recorded material stands out.

The system is by no means perfect but it is deeply satisfying. The next project is treating the room itself. My listening space is 12'x16' with a carpeted floor and double window. I plan to put drapes over the windows and then get some bass traps and acoustic panel.

At some point I plan on purchasing a MiniDsp Flex eight which will allow me to try DSP on the L300s.

Regards
Al

Below are some snapshots of the results using Dirac.

[Ian Mackenzie]

That is really cool.

Thankyou for posting your progress. The detail of the procedure was really interesting.

[alskinner]

Thanks Ian.
I forgot to mention is the default results in Dirac use are based on the Harman curve, which are quite good. As stated above the results can be modified by using the shelving and/or equalization within Dirac to taste. I am using version 3.65.

The M2 project so far has been one of the most rewarding and at times the most frustrating. It caused me to do tons of research in this forum and all around the internet. I knew that I would not be able to create a true M2 clone as I did not have the ports or the ability to do a curved panel at that time. So I compromised on a design that would match the dimensions as close as possible. Then starts the frustrating part. I knew I did not want to spend the money for the Crown amps that are used in the M2 implementation. I finally decided on a Minidsp 2x4 hooked everything up and loaded the equalization and crossover settings. One thing the Minidsp does not have is 36db Linkwitz-Riley crossover selection but has a 36db Butterworth. So I had to learn about biquads and created the Linkwitz-Riley. Hooked up everything and it sounded like crap. So I put my ear up to the high frequency driver and found there wasn't enough volume. Turned out that the Threshold takes more input voltage to reach maximum volume. Increased the high frequency gain in minidsp and I actually had music. I then decided to replace my aging amplifiers and bought the Parasounds and upgraded to the minidsp flex with Dirac.

As others have pointed out before a two way system is harder to implement correctly than a three way. I am well satisfied with the results, but understand that with more tweaks and room treatment it can be made even better.

I know I don't say it enough but I appreciate the guidance and comments on this outstanding forum.

Regards
Al