[icecast] Gain control

[William Goldsmith]

Excellent overview, Tim (as I'd expect - you da man when it comes to
broadcast processing :-).  I'd 2nd your recommendation on the Behringer
unit - for the price it just can't be beat & it sounds quite decent. I'm
using them on Radio Paradise, KPIG, & SmoothJazz.com.

I'd also recommend a *nix audio processing software app called ecasound. It
has an awesome agc/limiter patch - easily piped into the chain on an encoder
box. A bit CPU-intensive, but very smooth. I'm using it on Radio Paradise
(www.radioparadise.com) ahead of the Behringer.

-bg

> On Sun, Jun 24, 2001 at 01:51:05AM -0700, Dave Hayes wrote:
> > How are people doing gain control, out of curiosity?
> >
> > I know boxes exist (anyone have names and mfrs?) that ride the gain
> > for big radio stations, ensuring that there is no distortion and
> > raising the volume of songs recorded at a lower volume. I'd probably
> > buy one if I knew what to buy.
>
> This is a bit tricky and subjective.
>
> If you are doing streaming and broadcast, some considerations you
> will have are:
>
> * Brick wall filtering to prevent "all ones" distortion
>
> * Soft limiting and compression for increased loudness
>
> * AGC to reduce dynamic range to keep the music above
>   ambient noise (ie. office and car locations.)
>
> If you are just doing streaming and don't care about loudness or
> limiting dynamic range, you just need a smart clipper/limiter of
> some sort.  My favorite is the Aphex Dominator.  I have been using
> them for a bit more than 10 years for processing before A/D converters
> like Sony F1s and later DAT machines.  The Dominator does a great
> job of limiting those occasional nasty peaks (pops, clicks, feedback,
> etc.) without sounding like it is punching holes in the audio.
> The audio stays pretty "transparent" sounding.
>
> If you are in a loudness war (ie. broadcasting) and/or concerned
> about dynamic range you need some sort of AGC-compressor-soft
> limiter combination.  Aphex happens to make another favorite unit
> for this called the "Compellor".  It isn't as aggressive as other
> processors such as Bob Orban's, or Frank Foti's boxes but it is
> "transparent" with good AGC and some loudness.
>
> Both the Dominator and Compellor can be found popping up on Ebay
> at least once every couple of weeks.  Try to get the "Mark 2"
> versions of each unit.  The Compellor model 320 is their second
> generation unit.  If you are doing FM broadcasting, you need to
> get the dominator that support "pre-emphasis" such as the "722".
> I have picked up 320s for about $400 and the Dominators go for
> about $600.
>
> Of course Aphex will sell you their "combo" unit the "2020" for
> about $5K retail.
>
> If you want something cheaper (and of course not as good sounding)
> there are a couple of companies that build "compressor/limiters"
> boxes that run in the $150 range.  The Alesis "3630" or the Behringer
> "Composer Pro MDX2200" can do the job of hard/soft limiting and
> even some AGC/compression so long as you don't push them too much.
>
> If you are interested in a "how to" of setting up your new processing,
> drop me a line.
>
> Tim
> --
>   Snail: Tim Pozar / LNS / 1978 45th Ave / San Francisco CA 94116 / USA
>                POTS: +1 415 665 3790  Radio: KC6GNJ / KAE6247
> "It's a damn poor mind that can only think of one way to spell a word."
>                         - Andrew Jackson
> "What is wanted is not the will to believe, but the will to find out,
> which is the exact opposite." - Bertrand Russell, "Skeptical_Essays"
>
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