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PostPosted: Wed Feb 20, 2013 3:38 am 
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Quote:
I think there is more bigger problem for MB bands.
Using peek or RMS mode with FF makes Bands very hard to adjust to sound good / to keep spectrum.. etc.. but you get almost full "leveling" (read compression) if thresh and ratio is adjusted properly.

However, FB works way better but you lose some "leveling" with softer input from AGC (because of normal nature of feedback. So what's needed is, FB to act like FF - some 'double" releasing to fix that bad side of FB but to not lose linearity!

Currently with FB, to have most constant output with very different audio input, relays directly from AGC, and AGC is not so smart/fast to do that even though i tried several times to optimize 1-band AGC with SC EQ.
I think it's now better to use just one band for AGC with CS especially if I know that crossover between 2nd and 3rd band is super steep. Cutting bass in 2 bands mode makes things better (bass control), but in other hand worse (steep cut at 250Hz).
So maybe AGC just need better crossover between b1 and b2.
Let's see. What's the problem with FF for audio? Is it that you need to keep the bands wide (non-steep slopes, to avoid changing the spectrum) and then you get pumping? If so, the solution might be to use a side chain on the multiband compressor. One that reduces the amount of bass, mainly. And then you need to adjust the thresholds of the bands to match the new behavior. This would in fact also enable the use of RMS mode instead of peak mode.

But actually, the MB is *NOT* intended as a filter that adjusts the level - that's what the AGC should do; the MB also does something but it should only have a mild effect on the level.

FB which acts like FF will sound like FF - so that's not a solution! The attack and release behavior might be (very!) slightly different but the spectrum changes you mentioned would not be fixed at all, and neither would things like pumping.

If levelling is not good, the problem should be searched in the AGC, not in MB.

UNLESS....... Unless I use a compressor ratio like in the old compressor, where when the input level increases the ratio increases as well. Something like what's displayed in this image - the "Bad Knee" from a whole lot of beta's ago:
Image
Or some other smart behavior, such as a sliding feedback/feedforward behavior based on the input level. But if spectral content is an issue this could lead to Omnia 6 like effects. Will think more tomorrow...


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PostPosted: Wed Feb 20, 2013 4:06 am 
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If MB should have mild effect on level, then you can remove FF since FB is clear winner then.


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PostPosted: Wed Feb 20, 2013 7:24 am 
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Yes,

I agree with Bochja there probably are lots of things that can be removed since changing them will only make sound worse.
And it will give you some space for GUI at the same time :)

In MB i did NOT use the BURST PROTECTION since my ears heard some loss and distortion when doing so.
This is just a feeling i had and not concluded by measurement.

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PostPosted: Wed Feb 20, 2013 12:15 pm 
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I'm not sure if that's what Bojcha means... Anyway. Burst protection adds a compressor with attack time 1 ms - it should not add distortion except maybe at the moment a loud kick comes in. But most importantly, you need to set the levels such that the 1 ms compressor is not activated (displayed as red part of meter) for normal music.


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PostPosted: Wed Feb 20, 2013 12:21 pm 
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I'm looking at the AGC now and - with very aggressive settings - I see a very steep drop between 185 and 205 Hz. That drop should NOT be this steep at all. So something isn't behaving as it should.


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PostPosted: Wed Feb 20, 2013 4:04 pm 
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Quote:
I'm looking at the AGC now and - with very aggressive settings - I see a very steep drop between 185 and 205 Hz. That drop should NOT be this steep at all. So something isn't behaving as it should.
Ok. Problem is NOT that the filters are too steep (they might be but that's not the issue here). The real issue is that the response starts suddenly. Which is probably bad. I'll have to make some sliding scale. But that's not possible in the current AGC design. :(


Edit: Wow. There are 3 issues:
1. Filter is bad. Something weird happens just below 150 Hz. Normally this is hidden but if you set the "Keep band 1 at band 2 level..." slider to 1000% a weird bump appears. -----> CAUSE FOUND, this may impact other things as well. AGC was built upon the presumption that it's one of the first filters in the chain, but the steep highpass filter for band 2 causes problems. Solution known, will fix it.
2. Filter was too steep. That's now fixed, it looks nice and smooth - unfortunately the bump is now always visible.
3. Things work differently in Jump protection mode. This is not a sidechain issue (as Bojcha reported) but something is definitely wrong with band coupling here. --> No, was Remove remaining peaks. Fixed now.

Ad. 1: The AGC might act up when the declipper is active - even if it's not doing a lot! I know the solution (the new compressor already has it built-in, and even the old multiband compressor had it).


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PostPosted: Thu Feb 21, 2013 2:16 am 

Joined: Sat Nov 17, 2012 1:39 am
Posts: 36
I can't save different volume burst protection ratios for the multiband section. It always loads the band9 ratio for every band.

edit: can't disable it on individual bands either.

edit2: didn't see new version. everything now works.


Last edited by vmp94 on Thu Feb 21, 2013 4:04 am, edited 2 times in total.

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PostPosted: Thu Feb 21, 2013 3:44 am 
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Improved AGC behavior: Should work better if declipper or noise gate or multiple AGC bands are activated; band 1 to band 2 coupling is no longer sudden but smooth.
Added Multiband fast attack & fast release for burst protection (for testing, I expect I can remove them later again)
Burst settings are saved now (band number was missing so all the bands were saved under the same name before).

Stand alone: http://www.stereotool.com/download/ster ... 04-044.exe
Winamp DSP: http://www.stereotool.com/download/dsp_ ... 04-044.exe
VST: http://www.stereotool.com/download/vst_ ... 04-044.dll


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PostPosted: Thu Feb 21, 2013 4:32 am 
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ok.. played sweep 0-20khz with default 2-band default AGC settings (louder female disabled).
Here is result ..
Image


Then i freezed AGC in this position (both up/down speed to 0) http://i.imgur.com/JYwXFAt.png and played sweep again...
Image

Is that ok ?


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PostPosted: Thu Feb 21, 2013 7:33 am 

Joined: Sat Nov 17, 2012 1:39 am
Posts: 36
I gave the new volume burst protection a try and I'm impressed! In fact I'm so pleased with the sound that I will release the next GentleSlope with the deesser either hardly working or completely defeated. The volume burst protection really allows the multiband to be slowed down enough to completely eliminate multiband pumping. With this feature it might even be possible to mimic the 2-stage AGC/limiter multiband processing topology that many hardware processors have.

edit: Here it is. A transparent-sounding preset with multiband burst protection and without deesser.


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