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

  1. #1
    Senior Member Champster's Avatar
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    DIY 2235h, 2206h, 2446J Be or TAD 4001 and 2405H Build Thread

    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

  2. #2
    Senior Member JuniorJBL's Avatar
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    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.
    Always fun learning more.......

  3. #3
    Senior Member Champster's Avatar
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    Quote Originally Posted by JuniorJBL View Post
    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

  4. #4
    Senior Member JuniorJBL's Avatar
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    For most subwoofers to perform well they should be below 80hz IMHO.

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



    Quote Originally Posted by Champster View Post
    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
    Always fun learning more.......

  5. #5
    Senior Member Champster's Avatar
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    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."

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    Senior Member JuniorJBL's Avatar
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    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.
    Always fun learning more.......

  7. #7
    Senior Member Champster's Avatar
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    Quote Originally Posted by JuniorJBL View Post
    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.
    In order to get the 2206 to go that low, I'll need to change to a vented enclosure or add eq in the DSP with the sealed enclosure. I like this suggestion but was reluctant to use a vented enclosure for the 2206. What experience can you point to where a 2206 is used like this?

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    Senior Member Lee in Montreal's Avatar
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    Hi Champster

    If your plan had included an 18" 2245 instead of the 2235, then I would have said you have the right recipe for fun. Nothing to change. But with a single 2235 per cabinet, you will very soon find the limitations of that driver. If you go with 2235 woofers, may I recommand you fit two units per side. That's because they are not very efficient and you can't feed them with much power. While the 2245 is an "authoritative beast", the 2235 is its weaker baby brother...

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    To further elaborate and offer my understanding of Lee's post.
    The 2235 is the limiting factor as normally determined by the sensitivity of lowest freq. driver in a system.
    Not that it can't be done and work ok. It will end up as a targeted flat 93dB.

    At 1w/1m:
    2235 = 93dB
    2206 = 95dB
    C.D. and ring radiator > 100dB

    2245 = 95dB

    Personally I would go with the 2245 as well if building from scratch. I've not seen much if any difference in cost. It will need a larger cabinet of course.

  10. #10
    Senior Member Champster's Avatar
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    Quote Originally Posted by grey View Post
    To further elaborate and offer my understanding of Lee's post.
    The 2235 is the limiting factor as normally determined by the sensitivity of lowest freq. driver in a system.
    Not that it can't be done and work ok. It will end up as a targeted flat 93dB.

    At 1w/1m:
    2235 = 93dB
    2206 = 95dB
    C.D. and ring radiator > 100dB

    2245 = 95dB

    Personally I would go with the 2245 as well if building from scratch. I've not seen much if any difference in cost. It will need a larger cabinet of course.
    Lee and Grey- You guys are great! Thank you for that guidance. Since I am in the build from scratch mode, that will be a relatively painless swap.

    I'm on the prowl for a pristine pair of 2245's...

    Thanks again,
    Paul

  11. #11
    Senior Member Lee in Montreal's Avatar
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    The 2245 is a great driver. ;-)

    Lee

  12. #12
    Senior Member JuniorJBL's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    The 2245 is a great driver. ;-)

    Lee
    +1
    Always fun learning more.......

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    To show the difference, if you opt for brand new cone kits this is the latest price:

    C8R2235 $214.00
    C8R2245H $276.00

    Otherwise I've not seen used, good cond. units vary much.

  14. #14
    Senior Member Lee in Montreal's Avatar
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    Plenty of cheap 2240 baskets available to recone as a 2245. Look for baskets on your local Kijiji, not on eBay.

    As for crossing over, 12db/octave LR is fine and will sound natural. ;-)

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    Senior Member christo's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    Hi Champster

    If your plan had included an 18" 2245 instead of the 2235, then I would have said you have the right recipe for fun. Nothing to change. But with a single 2235 per cabinet, you will very soon find the limitations of that driver. If you go with 2235 woofers, may I recommand you fit two units per side. That's because they are not very efficient and you can't feed them with much power. While the 2245 is an "authoritative beast", the 2235 is its weaker baby brother...
    I’m with Lee on changing the 2235 to 2245. I just finished a 4344 set with 2235/2123/TD-2002/2405 and if I could do it over again I would just do a 3-way with 2245/2123/TD-2002.

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