Hello,
I do this stuff for fun. I assume that you do to.
First blush my impression was that the foam was a little odd, you know blocking the output of a carefully designed wave guide.
Then I gave it some more thought and got the idea that the foam may serve some purpose similar to what the wave guide is supposed to do in the first place but more of it. I see the foam shaping the beamwidth and or reducing the sound reflecting off the walls much the same effect as absorption material placed on the walls. I also see the off axis frequency response curves being completely different than the factory curves.
I kind of see the foam attached to the waveguide as flaps on a barn door spotlight.
I recently got a calibrated microphone and acoustic measurement hardware. When it quits raining here in Northern California I plan to go out in the backyard and do some frequency response testing.
Thanks DT
Attachments
Hi Norman,
Did you ever get a chance to listen or measure the M2 waveguide?
It seems available at: JBL M2 Horn Lens 5025594 - Speaker Exchange but have not called for a price.
Cheers,
Mitch
Did you ever get a chance to listen or measure the M2 waveguide?
It seems available at: JBL M2 Horn Lens 5025594 - Speaker Exchange but have not called for a price.
Cheers,
Mitch
Hi Mitch,
That M2 waveguide looks a bit complicated on the back.
Looking at the Speaker Exchange site there is a 8 hole adapter flange that is used to connenect the compression driver to the waveguide.
Do you know what bolt circle dimension of the D2 driver is?
Thanks DT
That M2 waveguide looks a bit complicated on the back.
Looking at the Speaker Exchange site there is a 8 hole adapter flange that is used to connenect the compression driver to the waveguide.
Do you know what bolt circle dimension of the D2 driver is?
Thanks DT
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JBL waveguides
Guys: considering these newer style waveguides are available, are the older horns you mention, like the 2344a still worth pursuing or using? I came a cross a boxed set yesterday that I bought years ago, but the project never got completed, with compression drivers. I was wondering what I should do with them. Heard some of the new JBL 100 re-issues today, and they sounded really good. I realize they don't have anything to do with each other, but it made me wonder if it is even worth messing with the 2344a now? I have new 2404H too.
Personally, I always liked the sound of the 2344a, but I have not heard any of these new ones.
Opinions?
Guys: considering these newer style waveguides are available, are the older horns you mention, like the 2344a still worth pursuing or using? I came a cross a boxed set yesterday that I bought years ago, but the project never got completed, with compression drivers. I was wondering what I should do with them. Heard some of the new JBL 100 re-issues today, and they sounded really good. I realize they don't have anything to do with each other, but it made me wonder if it is even worth messing with the 2344a now? I have new 2404H too.
Personally, I always liked the sound of the 2344a, but I have not heard any of these new ones.
Opinions?
Build with the 2344s. Look at the white papers on them. We're talking about dispersion when we talk of 100x100 - no matter the manufacturer. The 2344s will get you where you want to be if you're looking for that pattern. I currently have five different horn/CD combos and they ALL sound good, but I like 100x100 best. I can move anywhere in the room and still be in the sweet spot.
Hello Mitchba
I have done on axis measurements and worked out a passive network compensation for it. If you have CD driver with relatively smooth response it works out nice. I have to actually build up the speakers come spring been sitting on them for a while. Hear is an on axis with a passive network doing the comp and the high pass.
The bolt pattern is the same as 2431's and 2435's and 476Mg's
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JBL waveguides
Guys: Thank you for your comments. I started a project many years ago to build up a 4 way set of speakers, and acquired a whole slew of components, including a stack of TAD 12" mid-bass. I still have all the components, but life just got in the way. Changing jobs, moving three times, etc. But the biggest problem was that I lost interest in building the cabinets myself due to a back injury, and I couldn't find anyone to build them for me.
Frankly, after hearing the new JBLs' I'm tempted to just sell my stuff, and buy a pair and enjoy them. But seeing this post really got me thinking again. I have a new purpose built audio room in the basement, a new 7channel JBL Synthesis 7 channel x 160 watt amp sitting here, etc. And, most importantly, I have a cabinet maker to build anything I want at any time. Right now he is building us all new cabinets for our kitchen, baths, etc. A super talented guy who can run circles around anything I could ever dream of. In fact, I sold him all my shop equipment years ago.
Years ago, someone had sent me a schematic on a circuit that JBL used to correct for some performance issues with the 2344a, but I cannot remember what it was. That brings up the other point, I'm worthless when it comes to crossovers and design. I'd have to buy something. I do have a stereo 3 way active crossover but I don't know if I need more than that. It is one of those older Madisound Sledgehammer balanced adjustable deals.
Last but not least, If I did something like this today, I'd use AE woofers. Been up to meet John a couple of times in Green Bay. Love his products.
In the end, would I get that much more performance out of a set up like that?
Guys: Thank you for your comments. I started a project many years ago to build up a 4 way set of speakers, and acquired a whole slew of components, including a stack of TAD 12" mid-bass. I still have all the components, but life just got in the way. Changing jobs, moving three times, etc. But the biggest problem was that I lost interest in building the cabinets myself due to a back injury, and I couldn't find anyone to build them for me.
Frankly, after hearing the new JBLs' I'm tempted to just sell my stuff, and buy a pair and enjoy them. But seeing this post really got me thinking again. I have a new purpose built audio room in the basement, a new 7channel JBL Synthesis 7 channel x 160 watt amp sitting here, etc. And, most importantly, I have a cabinet maker to build anything I want at any time. Right now he is building us all new cabinets for our kitchen, baths, etc. A super talented guy who can run circles around anything I could ever dream of. In fact, I sold him all my shop equipment years ago.
Years ago, someone had sent me a schematic on a circuit that JBL used to correct for some performance issues with the 2344a, but I cannot remember what it was. That brings up the other point, I'm worthless when it comes to crossovers and design. I'd have to buy something. I do have a stereo 3 way active crossover but I don't know if I need more than that. It is one of those older Madisound Sledgehammer balanced adjustable deals.
Last but not least, If I did something like this today, I'd use AE woofers. Been up to meet John a couple of times in Green Bay. Love his products.
In the end, would I get that much more performance out of a set up like that?
The new jbl's ?
Meaning the m2 horn with the d2 compression driver ?
Hard to say.
My most impressive system i had was 2x18, 2x15, ev hp640, and piezo crossed at 80hz, 750, and 5khz, 24db L/R per side.
Now i look for a horn with less reflections (no parallel walls, no diffraction slot, no changing angles in horn path such as my ev hr90, a smooth shape of the mouth to the baffle). Even the m2 horn has a bit of a corner (mouth edge) i'd rather not see. But a tractrix (round and smooth) has a narrowing dispersion pattern.
I can't tell you what to get.
I know that the jbl 2384 horn is very nice, especially with a 2435hpl driving it.
Mostly, i prefer what i have to the double 15 crossed to 2384 horn.
Instead of "an infinite amount of reflections" on the jbl m2, how about minimal horn reflections ?
Oblate spheroid looks good, not so sure about the last change of horn path to baffle though.
The jbl synthesis looks pretty good, short horn with pretty flat mouth to baffle.
Best sounding horn I've ever heard is the mcm round horn now unobtanium with a jbl 2407.
Probably ususable under 2.5khz, maybe 2khz.
1st pic = jbl synthesis
2nd pic = jbl m2 horn
3rd pic = mcm 54-580 horn
Meaning the m2 horn with the d2 compression driver ?
Hard to say.
My most impressive system i had was 2x18, 2x15, ev hp640, and piezo crossed at 80hz, 750, and 5khz, 24db L/R per side.
Now i look for a horn with less reflections (no parallel walls, no diffraction slot, no changing angles in horn path such as my ev hr90, a smooth shape of the mouth to the baffle). Even the m2 horn has a bit of a corner (mouth edge) i'd rather not see. But a tractrix (round and smooth) has a narrowing dispersion pattern.
I can't tell you what to get.
I know that the jbl 2384 horn is very nice, especially with a 2435hpl driving it.
Mostly, i prefer what i have to the double 15 crossed to 2384 horn.
Instead of "an infinite amount of reflections" on the jbl m2, how about minimal horn reflections ?
Oblate spheroid looks good, not so sure about the last change of horn path to baffle though.
The jbl synthesis looks pretty good, short horn with pretty flat mouth to baffle.
Best sounding horn I've ever heard is the mcm round horn now unobtanium with a jbl 2407.
Probably ususable under 2.5khz, maybe 2khz.
1st pic = jbl synthesis
2nd pic = jbl m2 horn
3rd pic = mcm 54-580 horn
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Here is the schematic for the 4430. It has the compensation circuit for the 2344
Rob
http://www.jblproservice.com/pdf/Network Schematics/3134 Network.pdf
Rob
http://www.jblproservice.com/pdf/Network Schematics/3134 Network.pdf
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Thanks Norman and Rob. DT, Rob answered the bolt pattern q.
I have JBL 4722 with the 2384 waveguide and changed out the 3" 2432 CD to a 2453h-SL auquaplased Ti CD. Not bad response up high for a 1.5" exit:
The only two things I don't like is the notch between 12 and 13 kHz and wish for a bit wider directivity as it is a 90 x 50 pattern. I used a 1/2" spacer between the CD and waveguide, which helped reduce the notch. But looking at the throat of the waveguide and where the CD joins, pretty rough around the edges. I thought about taking a dremel tool to smooth out, but don't know if that would help the notch in the FR or not... Or is it simply the case with the large format 4" CD with a 1.5" exit..?
I have JBL 4722 with the 2384 waveguide and changed out the 3" 2432 CD to a 2453h-SL auquaplased Ti CD. Not bad response up high for a 1.5" exit:
The only two things I don't like is the notch between 12 and 13 kHz and wish for a bit wider directivity as it is a 90 x 50 pattern. I used a 1/2" spacer between the CD and waveguide, which helped reduce the notch. But looking at the throat of the waveguide and where the CD joins, pretty rough around the edges. I thought about taking a dremel tool to smooth out, but don't know if that would help the notch in the FR or not... Or is it simply the case with the large format 4" CD with a 1.5" exit..?
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Take a look at post 47 top trace that is also a large format 4" with a 1.5" on an M2 also JBL. If I remember the 2453 is in a shorter package above the top plate than say a 2451/52 so I think you may have a shorter phase plug. Similar to a 2431/2435. It can't hurt to smooth it out aka Earl G.
Rob
Thanks Rob - 476Mg - whoa!! Yes, the 2453 has the shorter phase plug. Maybe not a great match for the 2384...? I do like that the 2384 mates well with the double 15" at 630 Hz. I tried raising the XO to 800 Hz and it shifted the image up towards the waveguide and not inbetween the top 15" and wg. I can try smoothing our per Earl, but maybe I am wasting my time and should be looking at different waveguide and/or CD combo...
I wouldn't worry about that dip, it is way up there and better than a peak.
I'm not sure on a bigger horn, except maybe the klipsch big squarish thing (k402 39" wide x 25" tall, I'd subtract 3" minimum for horn lip mounting to baffle).
K-402 in wood! - Technical/Modifications - The Klipsch Audio Community
Bigger compression driver will go lower, but, now you have more frequency modulation and more eq needed (and maybe notching) to go up way high.
If anything, i wouldn't be happy with 12db crossover in the stock 4722n at 800hz. Maybe the caps bypassed by resistors in network help it roll some.
I'm not sure on a bigger horn, except maybe the klipsch big squarish thing (k402 39" wide x 25" tall, I'd subtract 3" minimum for horn lip mounting to baffle).
K-402 in wood! - Technical/Modifications - The Klipsch Audio Community
Bigger compression driver will go lower, but, now you have more frequency modulation and more eq needed (and maybe notching) to go up way high.
If anything, i wouldn't be happy with 12db crossover in the stock 4722n at 800hz. Maybe the caps bypassed by resistors in network help it roll some.
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Thanks Norman. Yah, the dip is no big deal, but being a diyAudio fanatic, I was looking for a possibility to improve the waveguide performance. Hence looking at different waveguides and CD combos. I did have a three way mains at one time with a BMS 4540nd on a QSC waveguide and still is the smoothest top octave I have heard/measured to date. I guess that is the advantage of the D2 with its dual ring radiator on the M2 waveguide...
Cask05 made mention of those K402's before and a kind member sent me some polars as well. Seems like an excellent waveguide that goes low, but kind of unobtanium.
I don't know about the stock 4722n's as I biamp mine at the recommended XO frequency from JBL with a linear phase digital XO using steep slopes. The drivers are time aligned with dual subs:Official Rythmik Audio Subwoofer thread - Page 1223 - AVS Forum | Home Theater Discussions And Reviews
Maybe the Celestion AxiPeriodic CD and red waveguide combo would be an audible upgrade...
Red horn ?
Nice.
The qsc waveguide looks real good also.
Hard to say, the 2384 is very special, but it is deep. Nice rounded edges, sort of rounded conical, good mouth to baffle round over, and no hard corners. But it is a 600hz horn.
The jbl 2435hpl compression driver is very special driver, worth 1.1k in my book (new).
That's many moons of allowance for me.
JBL 2435HPL Driver 125-30001-00X - Speaker Exchange
Maybe os waveguide (slightly rounded) that rounds off slowly at baffle.
But then we'd have a large difference in acoustic centers also.
Ug.
Norman
Nice.
The qsc waveguide looks real good also.
Hard to say, the 2384 is very special, but it is deep. Nice rounded edges, sort of rounded conical, good mouth to baffle round over, and no hard corners. But it is a 600hz horn.
The jbl 2435hpl compression driver is very special driver, worth 1.1k in my book (new).
That's many moons of allowance for me.
JBL 2435HPL Driver 125-30001-00X - Speaker Exchange
Maybe os waveguide (slightly rounded) that rounds off slowly at baffle.
But then we'd have a large difference in acoustic centers also.
Ug.
Norman
Attachments
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Thanks Norman and Rob. DT, Rob answered the bolt pattern q.
I have JBL 4722 with the 2384 waveguide and changed out the 3" 2432 CD to a 2453h-SL auquaplased Ti CD. Not bad response up high for a 1.5" exit:
The only two things I don't like is the notch between 12 and 13 kHz and wish for a bit wider directivity as it is a 90 x 50 pattern. I used a 1/2" spacer between the CD and waveguide, which helped reduce the notch. But looking at the throat of the waveguide and where the CD joins, pretty rough around the edges. I thought about taking a dremel tool to smooth out, but don't know if that would help the notch in the FR or not... Or is it simply the case with the large format 4" CD with a 1.5" exit..?
Hello,
This stuff is interesting.
You look at the measurement graphs of all of these waveguides and compression drivers they all have ripples. It looks that the cone and dome drivers have similar frequency response issues.
Thinking about it, a 1/3 octave band graphic equalizer can do a lot to help to smooth out the frequency peaks and dips. Then again the frequency response peaks and dips may not line up with the 1/3 octave band frequencies of the equalizer. I may be trying to slice the peach in too thin of slices, I don’t know.
Seem like a couple of moderate peaks and dips between 10KHz and 20KHz, you know the top octave, may not be all that audible anyway.
I like the way these 100 X 100 ish waveguides sound in my small playback space. The 90 X 50 ish and tighter waveguides seem to be too focused for my taste.
I did order a pair of the M2 waveguides to checkout with different drivers in my playback space.
Thanks DT