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Small mixer with AGC feature for PEG cable channel feed

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david soriano
Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 2:13:21 pm

I run a small PEG Govt channel that feeds our provider (Charter). It's an analog audio/video feed that gets converted to a fiber feed via a Phillips & Siecor converter unit.
My issue is that the audio range i have is limited before clipping occurs and distortion ensues. Other issue is that our channel's audio levels are low so i try to push the levels as high as possible without having the clip, but invariably they do due to variations in audio levels from different source programs. I've brought this up with Charter and they say everything is square on their end.

I run everything out of a Rushworks A-list media server, XLR to a Mackie 402VLZ4 mixer, where it outputs 1/4" to RCA in to the fiber converter. Is there a mixer out there that offers Auto Gain Control or has some other feature that would allow me to have the audio levels peak at a certain point but not exceed it? I assume it would have to be a digital mixer. I have a budget of up to $1,000, but would think i would not need that much to get what i need. Any help appreciated.

Alternatively, is there a software option for the A-list, which uses a Matrox card?


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Ty Ford
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 5:16:30 pm

Hello David and welcome to the Cow Audio Forum,

Is it a case of greatly varying levels or is it just that you can't get loudness and the levels are relatively consistent? You may just need a good comp/limiter. You may need a lot more.

We have seen the levels in local broadcast go wildly off from spot to spot. That's different than normal audio processing.

The local stations have solved the wildly varying elves with hardware from Linear Acoustics in Lancaster, PA.

Otherwise, it's usually a compressor followed by a limiter. AGC alone is seldom good enough.

If it were me, I'd be looking at an Aphex Compellor followed by an Aphex Studio Dominator.

http://www.aphex.com/products/320d-compellor/

I'm not even sure if they make the Studio Dominator anymore, but you could iron out a lot of bumps in your road with a Compellor. It has both analog and digital I/Os.

Regards,

Ty Ford

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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david soriano
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 5:39:55 pm
Last Edited By david soriano on May 6, 2014 at 5:52:46 pm

Thanks for reply.

The levels aren't that consistent but more importantly the loudness is not what i would expect or want it to be, compared to the other channels.

I checked out the Compellor, thanks for link. The input on the fiber converter/transmitter is a dinky RCA audio, so i would have to stick the Compellor between the Rushworks A-List audio XLR out and the Mackie XLR in, which would be fine, correct?


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Ty Ford
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 5:51:15 pm

then a compressor followed by a limiter should work.

Regards,

Ty Ford

Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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david soriano
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 5:55:11 pm

If both those go BEFORE the Mackie i'm still good as far as preserving effect/enhancements, correct? I need to get to RCA unbalanced to feed the fiber transmitter.


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david soriano
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 6:19:46 pm

yeah, not finding that Aphex Limiter available anymore...any other suggestions to pair it with the Compellor?


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Ty Ford
Re: Small mixer with AGC feature for PEG cable channel feed
on May 6, 2014 at 9:40:10 pm

David,

A dbx limiter somewhere in the middle of their line or above should work just fine.

Do you need mono or stereo?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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david soriano
Re: Small mixer with AGC feature for PEG cable channel feed
on May 7, 2014 at 2:25:29 pm
Last Edited By david soriano on May 7, 2014 at 2:28:00 pm

mono

So if the Compellor calls itself a compressor & limiter and a DBX unit calls itself the same does the same that doesn't mean i don't need both units?


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Ty Ford
Re: Small mixer with AGC feature for PEG cable channel feed
on May 7, 2014 at 2:42:41 pm

The original 320 Compellor had a limiter in addition to its main function as a compressor.

Limiter didn't sound very good (I suppose because they also sold the Studio Dominator)

What you want is a compressor followed by a limiter. The compressor allows you to raise the level and reduce the dynamic range of the signal. The limiter puts a cap on the level to keep it from distorting and further deceases dynamic range. The end result is LOUDER AUDIO without clipping.

You are, in fact, technically distorting the audio with each step, but that's how it works. Poorly designed circuits reveal their shortcomings by producing audible audio artifacts. The Compellor is very transparent.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Jon Rauch
Re: Small mixer with AGC feature for PEG cable channel feed
on Jul 10, 2015 at 3:05:00 am

Hi David,
I operate a PEG channel in Washington and have the same problem. My workaround was to run the rca output of the playback unit into an Alesus 3632 Compressor/Limiter which raised the level and stops it from clipping. There's an XLR output from the Alesus, and I screw down the positive and negative wires to the fiber transmitter input and the channel is louder. However not as loud as the surrounding channels. Our cable company uses only the left channel for it's PEG, if we were stereo I think we'd be on par with the other channels.


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david soriano
Re: Small mixer with AGC feature for PEG cable channel feed
on Jul 10, 2015 at 1:31:17 pm

i got a DBX 1066 that seems to have fixed problem once i dialed it in correctly.


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Brian Reynolds
Re: Small mixer with AGC feature for PEG cable channel feed
on Jul 12, 2015 at 6:38:35 am
Last Edited By Brian Reynolds on Jul 12, 2015 at 9:33:39 am

What you are needing to do is pad the output signal from +4 (pro level) down to -10 (consumer RCA) level.

So you need a 15db pad to get the units matched correctly, putting in 'active' gain controls only add noise and weak links into the chain.

For just a few cents worth of resistors you can get the levels right....
http://www.uneeda-audio.com/pads/


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