Placement of AGC in signal chain?

[petsy]

I'm trying to improve my studio with some AGC automatic gain control units. Thinking of getting a couple of Compellors as I've heard good things about them. A little unsure about the normal placement of these in the audio chain though. How are normally used - straight after the mic preamp or on the sum mix? Or both? Or maybe there are different schools for this type of thing.

FWIW, I mainly do talkshows so 90% of the material is talk, in-studio and over-the-phone. I would use AGC to smoothen out the levels to get even more symmetrical audio, without artifacts or distortion. Transparency is key.

Thanks.

 

[SRP]

If you're running just a mic preamp with no processing, replace it with a DBX 286 or something similiar.

The Compellor would go from the output of the board (program bus if you're using a radio console) to whatever you're using to "transmit" with (a recorder, a streaming encoder, etc.)

Instead of the Compellor, you might want to consider getting a full-blown audio processor app like Breakaway Live - it works VERY well for talk.

 

[petsy]

Thanks for replying. Yeah, I have a processor already, a Symetrix 528e. Or actually I have two of them, one for each mic. Great units I must say. I don't use the preamps in them as my console pre's are quite good but the effects are patched in on each mic post-preamp.

The reason I was thinking of putting a Compellor BEFORE the Symetrix, was that I've heard from several people that it's common to use AGC prior to processing. But maybe they were referring to broadcast processing and not voice processing. I've used a Compellor-type unit on the phone hybrid for many years with good results. But of course, a phone line is quite different from a voice mic.

Would you say there's no point at all in having a Compellor before the Symetrix?

 

[WNTIRadio]

That would be a waste of a Compellor. The compressor on the 528 is decent for processing voice... fast attack and release. It can sound muddy when pushed too hard. It's also assumed that you'll have some form of processing after the mic processor (such as a broadcast processor or similar item) in most applications. Putting the Compellor after everything will smooth out the whole mix and also somewhat limit it with the fast limiter function enabled.

 

[SRP]

Would you say there's no point at all in having a Compellor before the Symetrix?

Technically it's not possible to do that. The Compellor doesn't have a mic preamp. You could put it after the 528E, but IMO it's a waste of the Compellor.

 

[petsy]

Well, sure it's technically possible since I'm not using the pre's in the 528E but alright, thanks for all your answers. Seems like that might be overkill then. I record in mono so I guess I can always use the second channel on the Compellor I will put on the phone hybrid, to AGC the summed mix?

WNTIradio: Yes, I absolutely do some processing before "broadcast" (or in my case, upload). EQ, limiting etc. I must've just misinterpreted what the folks said regarding vocal chains. The Compellor will definitely go on the sum mix though, as I said. For the smoothening effect but also because my console doesn't actually have a master volume control (it's a Sixmix). So having the Compellor on the program output would effectively give me a master volume knob.

Again, thanks.

EDIT: Btw, regarding the 528: yeah, I really like it and it performs well for my purposes. I have everything except the EQ engaged. I don't do very heavy compression so I've not pushed it to those types of extremes where it colors the sound. I was gonna go with an ebay'd TC Gold Channel for my vocals but I'm kinda tired of displays and digital settings, plus it didn't have a phase rotator like the Symetrix and I really like what that does to my low middy type voice.

 

[chriscollins]

In the fashion that you are using it, I would place it last in the audio chain, before your soundcard.