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Low pass crossover setting & slope for Kappa 9?

I have a pair of Infinity Kappa9 speakers and need to buy a preset module for my AR EC22 crossover. I do know, that the Kappa9 spec sheet shows 80hz but that seems low for an external crossover and the specs do not show the slope speed, 12, 18 etc. I can obtain a 90hz with slope of 12 but not sure if this would be ok? I would like to know the exact setting and slope if possible. Thanks
Preamp- Audio Research SP10
Top end amp - Audio Research Classic 60
Low End Amp - Threshold S500
Speakers - Infinity Kappa 9
Crossover - Audio Research Ec 22
denniscleo
ngjockey
1,042 posts
 
Don't bother with Infinity. Asked the same question 10 years ago for the kappa8's and they had no idea. I don't think Infinity ever published exact specs. Bill at MillerSound might know.

Ask him if the 9's hi-pass/low-pass on the PCB can be bypassed.
denniscleo OP
1 posts
 
Yes, I did call Infinity but they did not return my call. I will give it another try next week. I was just hoping that there were some Infinity fans out there that have used the Kappa 9 in a Biamp application and/or is currently using a external crossover on the Kappa9.
Thanks....Denniscleo
ait
480 posts
 
Here is a link to an excellent Infinity site (in German) and the specific page for the Kappa 9, listing crossover points.

http://www.infinity-classics.de/infinity/models/Kappa-series-1987/index-Kappa.htm
ngjockey
1,042 posts
 
Looking at the schematic, it would be easy to bypass the low-pass, wiring directly from the terminals to the woofers. Easily reversible. The high-pass can't be bypassed without digging into the PCB, which requires expertise.

The low-pass is unusual, combining a low frequency filter and what looks like a 6db/oct, first order. The subsonic filter is optional if the amp is up to the challenge. Some active crossovers incorporate their own 20 Hz rolloff. A one or two ohm, high wattage series resistor can be added to increase impedance but gain will have to be adjusted.

High pass (mid bass coupler) looks more like a backwards 18 db/oct bandpass.

Crossover points could be asymmetric as well.
afc
141 posts
 
Might be a dumb question, but why do you need an active crossover? The way these are set up, if you remove the metal insert between the twin binding posts, you eliminate the
crossover at 80 Hz....you drive the woofers with the low end amp and the mid-bass and up with the high end amp. Worked well for me with an Aragon 2004 MkII for the bottom and an ARC D-130 for the top. Sounded good, but I still didn't have enough current to drive the damn things. Infinity told me that at high loads, total resistance can dip below 1 ohm. That's a load that requires an amp with some serious current. Kept blowing fuses on the Aragon, and the D-130- admittedly not ARC's finest piece of work by a longshot- kept going into protect mode after prolonged listening. What exactly will an active crossover add?
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