How to hook up compressor for ducking of music for speech

James85

I am setting up a PA for a skateboarding contest. I'll be playing music via laptop, through an adapter, and into two XLRs (stereo) on my board. I will also have an announcer on a wireless mic. I would like to set up one of my 266XLs to duck the recorded music when the announcements are made.

I tried searching on line and here but could not get a definitive explanation on how to hook up the compressor, sending the narration signal to side chain, aux?, etc.

I am sure someone here knows.

Thanks,
Jim

Gadget

Been thinking about this for a bit and I'm not sure you could get the "control voltage" (side chain signal) necessary to trigger the compressor from a vocal signal... but...you'd want to get the compressor inserted into the channels with the music. You would then take the output of the vocal channel to the sidechain input of the compressor.

The theory is that as the voice triggers the side chain, the compressor would clamp down on the music... to make this happen, you would need to interrupt the signal inline somehow.. so, with an insert in the music channel the sound is then sent out for processing on the tip of the 1/4" and returned (processed) on the ring of the insert (stereo/balanced 14" jack) AND be able to adjust the level of the voice (used to trigger the compressor) independently of the output signal...thus the signal sent from the channel strip as in an aux send.

In theory, a loud signal (such as a drum hit) is used to control some other event... thus my concern that a normal voice in a normal tone might not be able to provide enough voltage to trigger the event... but it's worth a try...no harm can really come with line level signals..

Gadget

James85

Thanks. You are not the first guy to pause when I asked the question. But the advice was the same.
I first heard about compressors and ducking from DBX's Compression 101. The paper gives some settings to try. The hook-up was vague or I just did not get it. I looked on line and I something on it from Ashly.

I was going to try it tomorrow but the event got rained out. Next Sat I may try it. I did buy a Rolls ducker box. http://www.rolls.com/product.php?pid=du30b

It is nice in that it is a very small box with the settings labeled for ducking. I tried it on my sons practice rig and it works. The thing is you run the mic into the ducker via XLR. The music input is stereo RCA. The output connections are a single RCA pair. There is a gain knob for the mic, the music level appears to be set by the "player device"..laptop, and entire "mix" gets controlled by your mixer. I can tweak the ducking sensitivity and release rate. Easier than yanking a compressor out of my rack..which is packed into my trailer.

With the compressor I can use a channel fader for music and one for voice to get the PA levels set. Then it seems like I have to tweak the compressor to duck the way I want it. The Rolls box appears easier. Maybe it is all the same in the end.

Report to follow.

Jim

Dra

I have (in storage) a 5 channel B'ger DJ mixer that has that feature built in. Threashold / sensitivity and amont of "duck". It is a good feature to have for hands-off, open mic and background music.

DRA