Active Crossover Recommendations


I want to experiment with using an Active Crossover to seperate high frequencies (going to my Quad 988's through Cary EL34 triode amps) from low frequencies (going to self powered subs by TBI or an ACI Titan). Can anyone recommend a good active crossover with a steep slope for this application. I would like the Xover frequency to be somewhere between 80-120 hz, best case around 100 hz.

Thanks very much for your suggestions.
peter_s
It may seem cheap, but there are a lot of positve reports on using Behringer DCX2496.
It's not the price of the Berhinger that puts me off, but the fact that it appears to digitally upsample and then downsample to do its crossing over. I can't imagine that would be good for the signal, even at 24/96. Kenn39 - what have you heard about its application?

I purchased a used Bryston 10b-sub, and will give that a shot. The distribution of frequencies that they chose is not all that suitable to my desired 120hz Xover frequency: they use:

50, 60, 70, 80, 90, 100, 200, 250, 300, 400, 500.

Bryston will change out the resistors at a cost. I will play around with the available frequencies, but think I may modify it to:

70, 80, 90, 100, 110, 115, 120, 130, 140, 160, 200, 250

The rolloff slopes are choosable b/t 6, 12 an 18 db/octave. It may be worthwhile to leave a gap between high pass and low pass, and I'm not sure how big of a gap, that's why I'm thinking of using high resolution around 115 hz, my target area. Any thoughts or suggestions?

Thanks, Peter S.
wouldn't ever do that to my signal, although it is probably very effective frequency wise.
Peter, I first read about the Behringer on the Newform Research Speakers website: http://www.newformresearch.com/digital-systems-overview.htm

There are many posts on various forums by people who use it to do bi-amping.

The Behringer does not resample. It does A/D and D/A to do the processing in digital domain. The conversions may be a concern. The digital domain processing provides a vast array of options though.
Peter, I've fooled around a bit with active crossovers altho with no CURRENT products. I believe:
1. You'll find virtually no difference between any 3 adjacent frequencies in your string beginning at 70; they're just too close together. IOW, there's simply not enough difference between/among 100, 115, and 120, to pick just 3. The only 3 with enough split are the last 3.
2. I strongly recommend you use a single-order slope on the hi-pass filter to the Carys and that it be a 'passive active' filter, meaning no more than a series capacitor, and a VERY-high-quality one at that. Your Cary/988 backend is probably VERY resolving, and probably you'll hear the circuitry AND the additional cables AND all the additional connections if you use an active filter. Think about how many mechanical and solder connections you'd add to the signal path with an electronic crossover!
3. I suggest you use the lo-pass filter(s) in your powered subwoofer(s).
4. I suggest you use stereo subwoofers. There is indeed directionality to bass frequencies.

IMO what you need is a soldering iron, knowledge of your amp's input impedance, and a few hi-quality caps. I suggest you experiment with crossover frequencies (=cap values) using SoniCaps. When you've decided on a frequency/capacitance, replace the SoniCap with a SoniCap Platinum or AT LEAST a Cardas Golden Ratio, the 2 finest caps I've ever heard.

So...save your money by NOT buying an electronic crossover, experiment with cap values, and enjoy superior sound thru your system. BTW I think you'll end up with a LOTS-lower hi-pass crossover frequency than 100 and above.
.
Jeffreybehr's suggestion is a good one if a 6dB high pass is OK, and for this application it is. However, I believe that a good electronics X/O would do the job without audible degradation.

My only caution is that this fixed capacitor approach does not give you flexibility to easily change the X/O frequency. I have recently concluded, after years of seeking the "right" frequency, that there is no "right" frequency for all music. So I have a X/O that is easily changed with the twist of a knob.