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RE: Behringher UltraDrive DCX 2496 as a compressor

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The Sound Guy

In Reply to: RE: Behringher UltraDrive DCX 2496 as a compressor posted by Zero Cool on June 15, 2008 at 08:48:55

Thanks for that very informative post. You say:
"The DCX has 2 compressor sections. Overall compression and frequency selective compression plus a 3rd section for brick wall limiting."

Is it possible to do frequency independent compression? It seems that compression is frequency dependent :-(

I'm not really sure how you manage the paging or vocal setups! Assume you compress the frequencies from 500Hz to 5kHz wouldn't the other un-compressed frequencies get louder? For example in the paging scenario, if it is setup so that the vocal frequencies are compressed and I play music, wouldn't the uncompressed sounds from the bass guitar be louder than the compressed vocals and ruin the speakers? Am I missing something? Maybe you could post the EQ settings you use?

Follow Ups:

RE: Behringher UltraDrive DCX 2496 as a compressor - Zero Cool 05:21:57 06/17/08 (1)
When you compress something. the differences between quiet sounds and loud sounds becomes less. Quiet sounds get louder, loud sounds get quieter so to speak in simple terms.

Every scenario is different so me posting my settings would be completly useless to anyone not in the same room with the same PA etc.

But you are right about the frequency ranges. when you compress say 500-5K everything in those bands gets louder in relation to everything else. With a paging application this helps everything in those ranges be heard at low volume levels. and helps limit loud surges. Everything below is at a lower volume level and I usually do a little EQ to roll off the bottom end anyway to protect the speakers.

Lets say you have a snare drum. everytime the drummer whacks that drum there is a very large peak. if you try and record this. you have to turn the level way down so those peaks don't distort. If you put a compressor in front, then those large peaks get squashed a bit and what happens is now you can turn the input to your recorder up a bit more before it distorts. everything else in the background then comes up with that level. the difference between the quiet background noises and the peaks is now much smaller.

For guitars this can help bring out harmonics and help hold sustain longer.

In the instance of my singer. he is used to hearing the monitors compress a bit when they get real loud. so to trick him, i set the compressor lower in overall volume level. he hears the compressor kick in and he thinks its louder then it really is!!!

The overall compression in the DCX is frequency independent. the frequency selective section you can compress frequency ranges and bring the overall level of that range then up or down. so i squash a section then bring that level up to to compensate or sometimes higher to bring that section to the front. this is all old school sound guy tricks that i picked up years and years ago by guys that really knew how to get the most out of old altecs and 30 watt mac tube amps for PA use cause thats all they had!
- RE: Behringher UltraDrive DCX 2496 as a compressor - The Sound Guy 06:16:54 06/17/08 (0)
  Thanks for the quick reply but it is still unclear :-(
  Yes, I understand how compression works and it is generally used on individual mic signals (before being mixed) if issues like vocalist or snare drum compression is needed. In the case of the DCX 2496, my assumption is that the compression is happening after the final mix (since it is usually connected between the mixer & amplifier) and that the compression is frequency dependent. So if no other compressors are used and the Behringer is set to do dynamic EQ from 500-5000 Hz (approx vocal range) for -6db gain and a -20db threshold, when the vocalist goes to 0db in the mix, the output from the DCX 2496 is -6db. But if there is a bass guitar at 0db, (assuming that most of it's signal is below 500hz) it will not get compressed and be output to at 0db and hence overdriving the cheap paging speaker. Is this correct?
  
  Is the compression on the DCX 2496 frequency dependent or not? You say it is frequency independent. Then why do we key in the frequency? Unfortunately I do not have access to the unit at the moment. I could access it after a few days if necessary.

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