Klipschorn + JBL 2350

Here's my latest. Klipschorn bass bin; JBL 2350, 2470; Bob Crites tweeters. Stock Klipsch AK-3 crossover (400Hz and 6k)


That JBL horn is exactly the perfect size. I'm surprised: I thought with a 1" driver and the throat adapter, it might be too deep. But no, fits like a dream.

Sound: a tiny bit toppy (the 2470 could use a little bit of attenuation) but amazingly good. I'll run some measurements later, see how the 400Hz crossover really suits the 2470/2350 combination.


(couple more pics here:)
http://www.flickr.com/photos/hughpyl...n/photostream/

Well Done Hpyle.:applaud:

I like the way you have made it in white. The 2350 seems to just float in air. I will remember that trick when the time comes. I like the 2350, but they are very hard to get in Australia. I must keep searching- you post has reminded me.

How do you find the intergration of the bass bin and 2350 at the 400 Hz crossover when listening? Looking forward to your measurements.

Best
JA

How does the JBL horn flare compare with the original Klipsch horn?

Are they the same width/length and have the same expansion rate?

Also, I'm in unfamiliar territory, but does the JBL horn/driver suffer from the same fate as the Klipsch in that 400hz is pushing the lower limit?

Project looks nice, just asking due to curiousity!

Thanks, Ron

JBL 2350: width 31.5, height 8, depth 20 (plus throat, adaptor, driver). Biradial with 220Hz cutoff.

Klipsch K400: width 18, height 7.5, depth 21 (plus driver). Tractrix... not sure what the spec'd cutoff would be there.

So they're in the same ballpark for expansion rate, but the JBL sounds to have cleaner horizontal dispersion; the Klipsch horn can be beamy. In both cases I guess a 400Hz crossover is pushing the lower limit; it's not quite an octave above the 220Hz JBL cutoff. But I don't think the alternatives are dramatically different (Altec 203B or 311-90, for example - I like the look of the 203Bs but they're several inches too deep!).

Anyway, here are some measurements - plotted with one-octave smoothing so you can see the forest for the trees a bit.
Blue: the Klipsch original, with Crites tweeters
Red: ...after the K400 swap for JBL2350
Green: ...after room correction (DRC)
The green trace is trying hard to equalize flat, but still shows a small dip around the 400Hz crossover point (where of course the time misalignment is huge, these folded bass bins), and a small rise around the 6k crossover.

Several take-aways from these measurements, for me:
- The 400Hz crossover point is just fine. Certainly no worse than before. I might still try 2482 drivers at some point, since those should be very comfortable down below the crossover point, at the expense of the broad HF range.
- With this (16ohm) 2470 driver, the JBL goes way higher than the Klipsch midrange, leading to the 6-7k bump I noticed. It's not that the driver sensitivity is mis-matched as I first thought, just that the treble extension is vastly better. Some EQ/DSP can flatten this a bit, or I could move the crossover point higher (8k?).

Enough with the math. It sounds good. Stress-free, punchy, clean, and very very detailed. Time to spin a few platters :-)

Quote:

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Originally Posted by hpyle

Green: ...after room correction (DRC)

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DRC?

John

DRC (http://drc-fir.sourceforge.net) and InguzDSP (http://inguzaudio.com). Source is a Transporter (http://www.slimdevices.com/pi_transporter.html).

Quote:

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Originally Posted by hpyle

DRC (http://drc-fir.sourceforge.net)

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Thanks! That should only take me a couple years to catch up on... :o: 'Looks very interesting, but I'll obviously have to read up on it to somewhat grasp how it does its magic...

John

Hpyle, that is one nice looking system! One thought I had as soon as I saw your picture is that you might want to try some room treatment. At a minimum you might try damping the side walls to catch the near field reflections. Hauling mattresses into the listening room from throughout the house would enable you to make a quick trial; just ignore any worried looks you might receive.

Good plan. I'm wondering how to add side-wall absorbtion without making it look silly (though my favorite Blake quote keeps me going here: "you never know what is enough until you know what is more than enough"...!).

Speakers are on the long wall of a fairly small room. So the listening position is only about a foot from the back wall, where I have some GIK panels already.

Quote:

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Originally Posted by hpyle

Klipsch K400: width 18, height 7.5, depth 21 (plus driver). Tractrix.

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FWIW the K400 are not tractrix but exponential.