JBL 4320 in a Karlson K15

keto · 9787

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Offline keto

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on: April 27, 2011, 12:21:37 PM
Not a bad sound, on-axis. Well, you really don't want to be off axis, with this combo! Just the 2-way "JBL 4320" version, 2215B woofer and 2420 tweeter, crossed over 2nd/2nd at around 800hz, and driven with a Paramount.

Tom Jones


Offline Paul Joppa

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Reply #1 on: April 27, 2011, 01:48:04 PM
Cool!

Just a note - the 2420 on that horn is flatter on a baffle board, and much less beamy with the slant-plate lens. I found some copies of the lens for $10, some years ago. I used a piece of 1x8, as wide as the cabinet - but it should really be a bit taller, 10 or 12 inches.

Paul Joppa


Offline keto

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Reply #2 on: April 27, 2011, 02:31:14 PM
I sort of prefer the directness of the sound without the diffusors and on-axis. Good to know about the baffle helping out. I've also got a pair of these 550hz horns on order: http://www.azurahorn.com/JBL2420_on_550.pdf.

Tom Jones


Offline xcortes

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Reply #3 on: April 28, 2011, 04:37:13 AM
Aren't the Karlsons supposed to be used in the vertical position? Did you try them both ways?

Xavier Cortes


Offline keto

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Reply #4 on: April 28, 2011, 02:04:17 PM
I haven't yet tried them vertically, since I'm working towards physically aligning the drivers, and that's easiest to do with them horizontally. After disarming the JBL enclosures I found that the tweeters were a 2405 (16 ohm) and a 2405H (8 ohm). Ooops. So, now I'm definitely back to a 2-way system! I'm curious to see if its possible to configure something with these horns in the nearfield. At the moment I'm getting lots of detail but not much integration.

Tom Jones


Offline xcortes

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Reply #5 on: April 28, 2011, 02:59:41 PM
Wow, you are basically using them as headphones! LOL

Xavier Cortes


Offline Maxwell_E

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Reply #6 on: April 28, 2011, 03:06:14 PM
Yeah, I don't know if you can get any more "near-field" than that.

I noticed the shot glass on the bench and I chuckled to myself. I did the same thing when I played sax. Unless that's actually gin :)

Max Tomlinson
SEX amp, Tode guitar amp


Offline Paul Joppa

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Reply #7 on: April 28, 2011, 05:29:49 PM
Just a thought - measure the DC resistance of the tweeter drivers. Some old JBLs are labeled 16 ohms but are actually identical to the later "8 ohm" drivers. And many drivers have had their diaphragms replaced with something different than the original part.  :^)

Paul Joppa


Offline keto

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Reply #8 on: April 28, 2011, 07:32:23 PM
Score! 6.2 and 6.4 ohms, so they might end up in my "large-ish headphone system" after all. Thanks!

Tom Jones