DIY 2235h, 2206h, 2446J Be or TAD 4001 and 2405H Build Thread

[Champster]

I thought I'd start a thread on my attempt to build a reference system that is one step more advanced than the JBL Synthesis K2 S9900. Although I have never heard the S9900, I love the design concept and am pretty sure it would rival, or exceed, many high end, audiophile systems. I am thrilled to get your comments (positive or negative) on my project. I realize that in any project like this, there are varying opinions on build theory and I won't bristle at your thoughts.

To start, a little background on me and my design goal. I am a life-long audiophile. This system is exclusively for my home listening room which is 19 x 15 x 9. It is a dedicated listening room and I have it set up as a live end (behind speakers) /dead end (behind listening position) and listen in the longer length of the room.

I have built, and purchased, many speakers in my 30+ year devotion to high end audio. Some of these, kind-of in order, include Infinity Beta Clone's, Wilson Audio WATT/PUPPY and WAMM clones, JBL L300, Altec Model 14's & 19's, Martin Logan (CLS and others), Entec, Muse and Velodyne subs, to name just a few. My latest love is dynamic, dipole speakers from Linkwitz Labs. I have built and owned the Orion and now the LX521. Check them out here. I consider the LX521 the most pure speaker I've ever heard and that includes some of the most celebrated audiophile speakers of all time (Soundlab, IRS, WAMM, B&W Matrix 800). So you ask, why am I building another speaker system? Fair question. The answer is that I love designing and building things and I want to build something that tests how close I can come to my LX521's as my Reference system. In the past, the one shortcoming in my efforts was the ability to analyze the output in a highly detailed, electronic way. I've always just used my, and a few buddies, ears. Well, we all know how accurate that can be.... Now with the creation of affordable DSP, the amateur speaker builder can analyze, evaluate and make changes much easier, cheaper and faster than ever before. So I'm awaiting delivery of my new miniDSP 4x10hd. In addition, I also have the Behringer RTA on hand. Luckily, Mr. Linkwitz has approved a DSP setup for the LX521 to replace my existing ASP. So, with that background, I came here to source what I know to be the best drivers available to see what I (with your help) can build.

To start, I'm not a big fan of the square box solutions (like the 4345) that JBL has historically designed. I've just never been able to eliminate cabinet resonances from big boxes. From a design perspective, I'm much more interested in the cabinets from the JBL Synthesis line. I'm thinking curves with lots of bracing using Sono construction tubing to make a D shaped cabinet. As the title of this thread discloses, I've sourced pristine pairs of the following: 15" (2235h) subwoofer; 12" (2206h) woofer; 2" Compression Driver (2446j) with a 2380 horn and (2405h) tweeter. I'm estimating the crossover points (all LR 24db/oct) at 100, 900, 8000, but those are subject to change with the miniDSP. I'm thinking 5 cf vented (tuned to 30 hz) cabinet for the 2235 and 1 cf sealed (.57 Qtc) for the 2206. I have read that mounting the woofer and midrange as close as possible is very important to achieve a seamless blend between the dynamic woofer and compression driver midrange and it helps to avoid the honking horn effect. I prefer to have an image that is slightly above my seated ear height (38") and plan for the center point of the horn to be about 45" high.

At this point, those are my design thoughts. I'm really going to give this the old college try and compete with the a great reference system that was designed by one of the most important contributors of speaker design in my lifetime. I'd love your thoughts, help and encouragement!

Thanks,
Paul

[JuniorJBL]

I am not sure that this will be very helpful but when I was looking to go down this path but with different drivers, I was told I should do a sub/sat system instead of a 4 way. You may also want to put Be dia's in your 2446's and run them all the way out without a band-pass (remove the low pass on the top of the band-pass).

You should also visit the REW forum http://www.hometheatershack.com/forums/rew-forum/ for a primer on speaker measurement and what can be done with it. I know GT recommends REW as a good starting point for doing speaker measurement.

Member 4313B did a "1200 Array" http://www.audioheritage.org/vbullet...ght=1200+array which used your 2206H and produced very good results.I would look into that as your primary means of attack. Use the 2235H's as subs.

I am by no means the end all voice for JBL s maybe others will chime in and correct me where I am wrong.

[Champster]

I am not sure that this will be very helpful but when I was looking to go down this path but with different drivers, I was told I should do a sub/sat system instead of a 4 way. You may also want to put Be dia's in your 2446's and run them all the way out without a band-pass (remove the low pass on the top of the band-pass).

You should also visit the REW forum http://www.hometheatershack.com/forums/rew-forum/ for a primer on speaker measurement and what can be done with it. I know GT recommends REW as a good starting point for doing speaker measurement.

Member 4313B did a "1200 Array" http://www.audioheritage.org/vbullet...ght=1200+array which used your 2206H and produced very good results.I would look into that as your primary means of attack. Use the 2235H's as subs.

I am by no means the end all voice for JBL s maybe others will chime in and correct me where I am wrong.

I don't know what the advantage would be to run a sub/sat system? I'm planning on using the 2235 as a sub up to 80-100 hz.

REW looks like a great tool. I have it downloaded. HTS is another great forum.

I hadn't seen this thread. Looks like a lot of good info. Thanks!

Thanks Paul

[JuniorJBL]

For most subwoofers to perform well they should be below 80hz IMHO.

I typically run mine at 55-60hz with an 18db slope. YMMV

I don't know what the advantage would be to run a sub/sat system? I'm planning on using the 2235 as a sub up to 80-100 hz.

REW looks like a great tool. I have it downloaded. HTS is another great forum.

I hadn't seen this thread. Looks like a lot of good info. Thanks!

Thanks Paul

[Champster]

No argument here. I totally agree with your sub crossover comment of keeping it well below 100 but I see a lot of people (even JBL) using the 2235 in 2 way systems. I assumed that meant it was very well behaved above the more prudent high pass cutoff of most subs. What tuning would you recommend for the tuning freq of the 2235? This is from 4313b's post. "I guess I'll find out if the "single fifteen in a small box going straight to the vertically oriented horn" ends up being the best implementation. The large single fifteen boxes that preceeded these dual fifteen boxes were also "28 Hz" boxes. The small single fifteen boxes are "35 Hz" boxes, still reasonably respectable for a wide variety of material. All the Everest II boxes are "31.5 Hz" boxes."

[JuniorJBL]

The 2206 will go to 50 hz without any help and do it well. So I would shoot for the 28hz-30hz box but that is my preference for subs. cross them somewhere between 50 and 70 hz. 4313B said the 2206 had fantastic dynamics so I would not worry to much about it.

[christo]

I thought I'd start a thread on my attempt to build a reference system that is one step more advanced than the JBL Synthesis K2 S9900. Although I have never heard the S9900, I love the design concept and am pretty sure it would rival, or exceed, many high end, audiophile systems. I am thrilled to get your comments (positive or negative) on my project. I realize that in any project like this, there are varying opinions on build theory and I won't bristle at your thoughts.

As for getting vintage JBL’s to sound anywhere near modern JBL speakers you won’t come close. I know as I have them side by side (4344/K2 S9900) and it is no contest. A beryllium compression driver in the 4344 helps with imaging but nowhere near what the 1500AL-1/476Mg combo can do. I have spent hours fiddling with my 4344s and have them sounding as good as they’re going to get, you can’t tell your listening to a horn speaker any more, but they’re no were near the K2s.