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stereo compressor AFTER crossover?

Discussion in 'Amps and Cabs [BG]' started by dadodetres, Jul 17, 2005.

  1. dadodetres


    Dec 19, 2004

    im putting toigether my rack...

    i wonder if it is a good choice to use a stereo compressor after the crossover, so i compreess low separeted from mid and high.

    my gear is:
    SWR Grand Prix
    dbx 266XL
    dbx 215
    Yamaha F1030 (crossover)
    Yamaha P3200 (power amp)
    SWR goliath Jr (2x10)
    Yamaha 1x18

    im using the SWR eq flat and eqing from 1 channel of the dbx215. crossover set to 250 Hz.

    what i though was the SWR into the 215EQ, then into the crossover. Each channel into 1 compressor, and each comp into 1 channel of the amp.
  2. Never heard of that. The odd effect would be the compression would affect the vol of each cab differently, so that would change the balance of power between the cabs as volume changed, therefore the tonal balance of the biamp.

    You'll never get them to track equally, so some tonal change will be unavoidable, even if the comp ratios are equal. Can you "gang" or "tie" the 2 channels together so they both track together? That's too clever by half.

    Simple solution?
    Why not run the compressor ahead of the crossover? That guarantees the tone of the combo of cabs doesn't change with signal/compression levels.

    Are you trying to use the compressor to protect the speakers, figuring they have different demands on them in biamp mode? That would work, but keep the ratios the same to minimize the tone change a the compressors vary the balance between the cabs dynamically. In that case, shoot for higher comp ratios, but have high thresholds so the compressors only kick in rarely, only when necessary.

    If you want regular signal compression instead of speaker insurance, better off with compressor before the crossover. My opinion. I think you're in relatively uncharted territory here.

  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You can do exactly that, with one channel for the highs, one for the lows, and different ratios/thresholds on each. It's done all the time in the studio.
  4. stringtheorist


    Jul 14, 2005
    This is essentially multi-band compression. It is widely used during mastering.
  5. dadodetres


    Dec 19, 2004
    the problem i have is when using the compressor at my effect procesor is than when i send a big low end sound, the highs disapear, cause the volume of the lows are way more.

    but, maybe cause thats because the comp is not good at all, maybe with the dbx things will be different, ill try both alternatives......
  6. You can do what you suggested, but keep it simple first. If there's one thing to learn (and I'm still working on it) the simpler the better.
  7. Doesn't that mess with the tone? Essentially the gain on highs vs lows is varying all the time?

    Still, I can really see this for slap. If the low thumb parts are triggering the compressor, and the gain remains down through the snaps, keeping them muted, this could work wonders.

    Still, its like playing with the balance between high/low sections in real time, especially with different ratios.

    If you're increasing the low end a lot with tone, could you try compressing pre crossover, but triggering the compressor with a pre-eq signal instead? Another option to consider? That would keep the low end from prematurely triggering the compressor, without altering the low/high balance dynamically.

  8. dadodetres


    Dec 19, 2004
    thant sounds good, ill try it tommorrow
  9. You can set to stereo link (assuming chA is master), connect tuner out to chA input to control when compressor kicks in.

    But route the actual mono signal through channel B before crossover. Then tuner (pre-EQ) signal controls the compressor, but not based on excessive low end EQ boost.

    Regarding the stereo compressor used post EQ, it SOUNDS weird when described. But if it SOUNDS good to your ear live, nothing wrong with it. Someone above said they do that in studio all the time, so its worth a try also. I didn't mean to discount that option, just suggesting another alternative to try.

    Your ears are the final judge of what sounds good.

  10. Doesn't the Sunn 300T have a split band compressor - one for the highs and one for lows, with a gain balance for the two signals? - except the 300T isn't a biamp, so I gues it recombines the signal afterwards...
  11. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    I use a Rane DC-24 Dynamic Controller. One reason it's my favorite is because it's a multi-band compressor: has a built in crossover and compresses lows separately from highs. For me it solves the exact problem you mentioned: big low notes squashing out all the high frequencies.

    Right now, your mono compressor is changing tone in a bad way. Running a stereo compressor after your crossover would give the same effect as multi-band compression, and I think it's a very good idea... it would restore the tone you lose from mono compression. So yes it would change tone, but in a good way. Good luck!
  12. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member


    I have a mono rig, and when I use my Rane multi-band compressor, I set it to recombine the highs and lows. I also have the option to leave them separate. I may one day experiment with a biamp rig.... I'd like to try overdriven highs and clean lows.
  13. stringtheorist


    Jul 14, 2005
    I use a similar technique when producing a track. Often if I want a real grimey bass sound I'll duplicate a track, run a low pass on one track around 120Hz and a high pass around 500Hz on the other... apply any (stereo) effects, distortion. reverbs, etc on the high track, and leave the low track clean and mono. Usually gives a very clean distortion.... if that makes sense. Distortion on real low frequencies tends to sound muddy to me.
  14. dadodetres


    Dec 19, 2004

    why not better go from tuner out to the SIDE CHAIN INSERT and use the regular OUT to the dbx IN, sdo i only use 1 channel of the dbx?