Topic: Can the ill-effects of AGC be undone to any degree?

[tungarbulb]

Recently I recorded a concert off the board using an Edirol R-09HR, 44.1K, 16 bit resolution.

It was a sweet show, but I switched on the unit's AGC by mistake. Most of the recording is all right (if a bit “mashed”), but there are some rather annoying level variations in places and drop-outs in relatively quiet passages when a percussion instrument is hit; the unit sets the level for whatever's loudest in the mix and drops everything else and takes its own sweet time releasing.

What can I do about this, other than putting a big, sticky piece of duct tape over the AGC/LIMITER switch on the back of this otherwise excellent unit so this doesn't happen again?

I use Adobe Audition version 1.0 (hey, it does the job just fine in most cases!). It supports Direct-X plugins, not sure if it'll run the VST kind.

[SmokinJoe]

Yes, tape over the limiter button.  I've done that on my R09 and R4.

To fix the existing show, I don't think there is a magic plug-in that will do a great job.  Asking software to somehow know where another software plug-in (your Edirol's AGC) went too far is not an easy thing to do.  Probably your best bet is to either (a) chalk it up to a learning experience, or (b) tediously edit the levels at the places where the surging in level seems to be the worst.

[tungarbulb]

Yes, tape over the limiter button.  I've done that on my R09 and R4.

To fix the existing show, I don't think there is a magic plug-in that will do a great job.  Asking software to somehow know where another software plug-in (your Edirol's AGC) went too far is not an easy thing to do.  Probably your best bet is to either (a) chalk it up to a learning experience, or (b) tediously edit the levels at the places where the surging in level seems to be the worst.

First, thank you for your reply.

I borrowed a machine which had Waves' Renaissance Compressor/Expander plugin installed on it (one of its factory presets is labeled "Hole Unpuncher", which sounded promising). But after hours of fiddling with it, it seemed to either have no discernible effect or actually made the program sound worse.

I was thinking of option (b), using the envelope function in Audition's multitrack view to manually attempt to adjust the worst "holes".

Or I may just resign myself to option (c), hope that a fellow taper whom I met at that show will share his copy with me.

It's 2011, dammit. Why can't they make AGC that doesn't demolish the sound of a good recording source?

[stevetoney]

A couple comments.  I've heard that there are some new recorders out there that have excellent and fairly transparent AGC...not sure which right off the top tho...Sony M10 and D50 maybe?

Don't feel bad about using Audition 1.0.   I've had the opportunity to upgrade many times in the past and while there are a few annoying quirks about 1.0 that I'd love fixed, I still prefer it on my machines to the newer versions.  The newer versions are RAM hogs on my slightly older machines and I find that 1.0 does everything I need it to, while running much faster.

[tungarbulb]

A couple comments.  I've heard that there are some new recorders out there that have excellent and fairly transparent AGC...not sure which right off the top tho...Sony M10 and D50 maybe?

NOW you tell me!

Don't feel bad about using Audition 1.0.   I've had the opportunity to upgrade many times in the past and while there are a few annoying quirks about 1.0 that I'd love fixed, I still prefer it on my machines to the newer versions.  The newer versions are RAM hogs on my slightly older machines and I find that 1.0 does everything I need it to, while running much faster.

Fast and functional is how I like my software. Funny how a lot of software writers, even in the open-source world, seem to assume that everyone buys a new system every other year!

[fmaderjr]

What can I do about this, other than putting a big, sticky piece of duct tape over the AGC/LIMITER switch on the back of this otherwise excellent unit so this doesn't happen again?

Use the menu to have the switch activate the limiter instead of the AGC. Then if you turn it on by accident you will likely hear no artifacts. If your levels are peaking below 0 dB as they should, the limiter won't kick in (and if by some mistake your levels go over 0 dB, the limiter may even help some).

[kylieshotpants]

Hi

I've managed to rescue recordings like yours, by splitting individual tracks into sections (when it goes vastly up or down), then tweaking these parts one by one then joining them back together- unless you spend ages on it you will hear the changes but it should be much smoother than the original

[tungarbulb]

Hi

I've managed to rescue recordings like yours, by splitting individual tracks into sections (when it goes vastly up or down), then tweaking these parts one by one then joining them back together- unless you spend ages on it you will hear the changes but it should be much smoother than the original

IOW, zooming in tight on the offending passages (in Audition) and manipulating the levels back to more or less normal manually?

[kylieshotpants]

Hi

I've managed to rescue recordings like yours, by splitting individual tracks into sections (when it goes vastly up or down), then tweaking these parts one by one then joining them back together- unless you spend ages on it you will hear the changes but it should be much smoother than the original

IOW, zooming in tight on the offending passages (in Audition) and manipulating the levels back to more or less normal manually?

I use cd wave editor to split the track into parts that go way up or way down, then wavelab 6 to tweek the parts, I found this easier than adjusting whole tracks as you can concentrate on the smaller details

[capnhook]

"Prime rib in, porkchop out", as they say here in the south.  Lesson # 13A on the learning curve..

[it-goes-to-eleven]

For a second I read this as "Can the ill-effects of AKG be undone to any degree?"

[DSatz]

About 20 years ago I engineered a classical music CD for a major label. The original analog tape recording, featuring a famous orchestra and conductor from the 1950s, had been made with a considerable degree of compression. (Compression is related to AGC although the dynamic behavior over time is somewhat different.) As the analog tape was being transferred to digital I sat with my hand on a gain slider, raising and lowering the gain along with the music for the entire length of the recording.

The CD got positive reviews, and to my knowledge, no one outside the record company was ever aware that this kind of thing was done. Just don't try to go too far--as I recall I only made about 6 or 8 dB total change in the dynamic range. I would never claim that the result sounds exactly as it would have sounded without the compression, but it generally sounds better and, I hope, in no way sounds any worse than before.

Where people get into the most trouble when trying to "fix" a problem recording is that they overuse whatever tool they're trying to apply. It's very important not to do that, since then the attempt at a fix can become just one more audible layer of the problem.

--best regards