JBL 2404 and ALK in KHORN

[ZAKO]

Markus ....I tried the L pad with passives ...Your right they sound VIAL. That went away tri-amping.

[John Warren]

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On 4/16/2005 9:46:25 AM DeanG wrote:

I think the notch circuit is a must to damp the resonance. I wouldn't run the JBL without it.

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Dean-

What the notch filter "buys" you is a very simple way to modify the output of the filter over the crossover region by just adding or substracting resistors. In other words, with a handful of resistors and an LMS setup, the crossover transition can be shaped to get a smooth transition. The notch filter makes things easy.

The predicted voltage response below is the 2404H circuit with (from bottom to top) 10, 20, 30 and 40 Ohm resistor value in the LCR. The filter is loading into a simulated 2404H impedance. I have LMS plots but they are not electronic format.

The 10 Ohm provided the smoothest transition on a Klipschorn using the AA.

[markus111]

Ok, after some extended listening with the 2404s, I have a bit more to add. Overall, the sound is excellent. The improvement over the T35s was well worth the price. Imaging is far better, transients are great, and there is considerably more detail.

I felt that it was a bit hot on the high end, so I went ahead and measured it. On my 31 band analyzer, it is 2db up at 6khz and 8khz, but then it drops back down and remains flat out to 16khz. If I am reading John's graphs correctly, it looks like it may be worthwhile to try the filter and play with that resistor value. I've got enough spare parts lying around, so I will give that a try this weekend.

Mark