Stereo Tool

I've seen the preset that you've mailed me, and things are starting to make sense. Your input volume (Pre Amp) is indeed very low - in many cases the output would come out of the AGC unchanged in BETA, and lowered a bit (upto 2.4 dB lower) in later BETA's. I'll have to check if I can do something about that... (I'm afraid that I can't, at least not without re-introducing the problem that the AGC doesn't do anything around input level = target level).

About your other post about behavior: The end result is the same. Personally I find my setup more intuitive - that's why I made it this way. But if you're used to the opposite setup I can imagine that it might be confusing or counter-intuitive.


Edit: Did some tests. I was wrong: The amount (aggressiveness) of compression did NOT get bigger (or at least only very slightly) due to the smooth start. And for low input levels the output volume is a bit lower so you can increase the target output level a bit, which completely removes any issues that were caused by this.

In the last version there was another bug (which does not seem to affect your preset though): If pre-emphasis was enabled but FM processing is disabled, the AGC was corrected to act on a pre-emphasized signal. But the signal wasn't pre-emphasized. Will upload a fix later.

Thank you very much, i say once again, this program is awesome, im using with professional 900rms amplifier and good speakers, i just use for enhance sound, with very very soft compression, IT ROCKS!!!!!!!! THANKS!!!!!!!!! KEEP UP GOOD WORK!!!!!

I missed this post before...

I'm measuring the RMS level over a longer period of time (96 ms, which is a single slice of audio at latency 4096 at 44.1 kHz).

Then I calculate how much the volume needs to be reduced.

Then I calculate the RMS level over shorter (256 sample) frames of audio. (Actually that's too short for an accurate RMS level determination, but I only need rough estimates here). And I spread the needed reduction over those frames. If they are all identical in volume, each gets the same amount of reduction - so it takes longer for the audio to drop.

For lower 'down speed' values that works fine, because you want a gradual drop. For high down speed values however you'll get the behavior that you've noticed. "Remove remaining peaks" should fix that.

I can improve this behavior further, but I'll postpone it for a later version - I think it's getting time to release version 5.10, it's a lot better than 5.00 so I really want to get rid of that version

Hi Hans
Since you changed last beta's AGC .. what you recommed for default settings now for two AGCs. ?
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For lower 'down speed' values that works fine, because you want a gradual drop. For high down speed values however you'll get the behavior that you've noticed. "Remove remaining peaks" should fix that.

Well, "Remove remaining peaks" does not do that .. even when it does, it do it in very bad way, because it do job very fast (peeks), so it make sound to vibrate when pushing down high level audio.

Please hold on... I couldn't stand the behavior I responded to in my previous post, and I'm trying to fix it - and it looks like it will give a huge improvement to sudden bursts of audio... Ow, and for high 'down speed' values, the loud part of the audio should be very short, so you shouldn't get that much vibration?

Bad thing though is that for constant beeps etc. the volume now drops in 'steps' - so I'll need to smooth that a bit to avoid annoying effects. (Basically, if the volume difference is bigger, it should behave more like the new behavior I'm creating now. For small differences, say < 10%, it should keep the old behavior.)

Exactly .. that short period is problem! and if you have loe Down-speed .. remove remaining peeks fix that short period but still active till agc is down.

Fixed, building now.

For some effects (FM Hot presets) I still need the old type of processing to better preserve peaks. If this new version is indeed better (and it should be, peak levels are greatly reduced), I'll make it switchable later.

I think i found very very good settings for AGC I think i solve many things. Still must check more.

Updated version.

Changes:
- Bug introduced in previous version fixed: FM pre-emphasis and AGC now work together properly again
- Down Speed behavior changed.

Old behavior:
- Split 100 ms portion of sound into smaller segments
- For each segment, calculate the RMS level in that segment
- Perform volume drop directly proportional to amount of audio within segment
This caused the delay: A constant signal has constant drops, so the 1st segment drops only slightly etc.

New behavior:
- Split 100 ms portion of sound into smaller segments
- For each segment, check if it's the loudest so far
- If it is indeed louder than anything before this one, drop the volume, based on how much of the maximum segment RMS level this is.
Delay is gone now, volume immediately drops very rapidly.
Note: This MAY cause some reduced punch, especially when a new loud punch starts.

Winamp DSP plugin: http://www.stereotool.com/download/dsp_ ... ETA008.exe
Stand alone version: http://www.stereotool.com/download/ster ... ETA008.exe
VST version: http://www.stereotool.com/download/vst_ ... ETA008.dll
VST version (No SSE2): http://www.stereotool.com/download/vst_ ... ETA008.dll
Command line version: http://www.stereotool.com/download/ster ... ETA008.exe


Remaining TODO's:
- Change AGC default values (I'll check Bojcha's and SuperH's presets)
- Update presets (especially FM Hot doesn't work anymore, and will work much better if I use 2 AGC's)
- (Probably) enable switching between old and new down speed behavior, to maintain punch for FM Hot preset (?)
- Pentium 3 behavior
- See Edit below


Edit: If I load the "FM Loud (Bass Boost) Europe preset, I hear a lot of distortion, which isn't there in version 5.00. I don't know what the difference is. It must be in the preset, because if I load this preset in BETA8 and then load 5.00, I still hear this distortion, and if I load the preset in 5.00 and then load BETA8, the distortion isn't there.... Will check this later.

Hvz:

As far as my preset, I've adjusted to your new AGC. I'm pretty content with this:


Such amazing progress!

Please feel free to incorporate this version of my optimization into your next release!