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PostPosted: Tue Oct 02, 2018 10:45 pm 

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 21
it has come to my attention since the audio is processed by "Auto EQ" before it reaches the AGC, it can be configured as a 9-band -12dB peak limiter to reduce sudden level jumps to the AGC which results in a more smooth evenly leveled AGC adjustment however, there is no adjustment for the gate control in "Auto EQ" for "kick speedup" which results in the adjustment levels "sticking" until audio is detected by the gate control.
the gate settings in "Auto EQ" appear to be "hard-coded" by design.
this creates a slight "wah-wah" effect in the sound with low volume changes (the gate moves slowly).
"Auto EQ" would be more effective for use as a 9-band peak limiter prior to the AGC if an option existed for gate configuration (better if it can be disabled).
attached is the current "Auto EQ" STS file adjustment i use as a 9-band peak limiter.
thanks !


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AEQ.sts [2.95 KiB]
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PostPosted: Wed Oct 03, 2018 11:33 am 
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Joined: Tue Sep 15, 2015 12:22 pm
Posts: 173
Hi!
Auto EQ is not designed as a limiter, nor is it its purpose to reduce sudden level jumps to the AGC.
Auto EQ balances the input spectrum. So if there's little bass and loud mids, it may cut the mids a bit and boost the highs. The total level remains unaltered, so it's not a compressor. This results in a more consistent sound even before the multiband compressor is hit.

Normally Auto EQ reacts slowly, but in case the spectrum suddenly changes completely, it may have to move faster temporarily. That's what sudden jump protection is for.

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PostPosted: Wed Oct 03, 2018 4:30 pm 

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 21
Quote:
Hi!
Auto EQ is not designed as a limiter, nor is it its purpose to reduce sudden level jumps to the AGC.
Auto EQ balances the input spectrum. So if there's little bass and loud mids, it may cut the mids a bit and boost the highs. The total level remains unaltered, so it's not a compressor. This results in a more consistent sound even before the multiband compressor is hit.

Normally Auto EQ reacts slowly, but in case the spectrum suddenly changes completely, it may have to move faster temporarily. That's what sudden jump protection is for.
understood but still, the way you describe Auto EQ is similar to the actions of a 9-band peak limiter if the boost level is kept at 0dB.
the goal was to "smooth" out the AGC using Auto EQ despite having the AGC configured in such a way as to *not* to move too much in level adjustments in order to prevent "pumping" to MB1 but some media content has great levels of sudden change which clearly affects the AGC, the configuration of Auto EQ significantly reduces this effect.
as it stands now, this configuration works quite well after testing which is why i made the suggestion about Auto EQ as there can be some content sources with greatly varying degrees in sudden volume levels at different audio frequency spectrum's.
to better understand, the configuration i use for ST is simple and designed not to be the "loudest" but to have loudness while preserving the dynamic peaks of the sound.
ive included the AGC & MB1 settings to give a better idea why i am using the Auto EQ to act as a peak limiter, i only use Auto EQ, MB1 and clipper.
AGC & MB1 was configured with white noise (without using Auto EQ) so the top end of the frequency spectrum for MB1 from 1Khz to 16Khz remains at the same level as the AGC output when MB1 is turned off.
i prefer the deprecated version of AGC as it has better handling of the incoming content using three bands instead of a single band.
in closing, it still would be nice if Auto EQ did have the option to be configured in such a manner to operate as a peak limiter prior to the AGC, this would further stabilize the AGC but preserve the peak dynamics.
feel free to test.
PS - abrupt change protection on Auto EQ really does not work too well when i test it, though the display shows better action, it seems to be quite weak when working.
seems to perhaps be a bug, when using my STS config for Auto EQ, setting "reduce effect" to 6dB and then activating abrupt change protection seems to work properly but turning it off and then back on, it stops working (white measurement lines at the top of the display disappear) - if you have trouble reproducing this effect, i can record it for you.


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MB1.sts [23.85 KiB]
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AGC.sts [11.61 KiB]
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PostPosted: Thu Oct 04, 2018 11:14 am 
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Joined: Tue Sep 15, 2015 12:22 pm
Posts: 173
Quote:
it still would be nice if Auto EQ did have the option to be configured in such a manner to operate as a peak limiter prior to the AGC, this would further stabilize the AGC but preserve the peak dynamics.
A peak limiter that preserves peak dynamics sounds a bit as a contradiction in itself... can you elaborate?
Quote:
when using my STS config for Auto EQ, setting "reduce effect" to 6dB and then activating abrupt change protection seems to work properly but turning it off and then back on, it stops working (white measurement lines at the top of the display disappear)
That is to be expected, it only engages again on a sudden level change. Also, it only reduces the effect of Auto EQ itself and never does additional compression or limiting.

_________________
Software Engineer @ Thimeo Audio Technology B.V.


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PostPosted: Thu Oct 04, 2018 5:00 pm 

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 21
Quote:
A peak limiter that preserves peak dynamics sounds a bit as a contradiction in itself... can you elaborate?
sure.
my MB1 as configured is primarily dependent on the action and level of sound from the AGC, the idea was to keep the AGC from moving too much due to sudden sustain/jumps of certain audio frequency sounds and while my AGC is configured as such to allow pass through of sudden jumps of sound to the maximum limit in the GUI, certain levels of audio frequency which are louder than the maximum limit as configured in the AGC will make the AGC move affecting the overall incoming level of other sound distributed to MB1.
the idea by using Auto EQ as configured, is to significantly reduce that effect whereas the AGC is minimally affected by the presence of high volume sustained/jumps of certain audio frequencies like a loud guitar or sustained bass providing a more even distribution of sound to MB1 for processing.
the Auto EQ does not hard-peak the incoming audio, it is operating more like a "soft-limiter", while it does reduce the effect by -12dB as configured and attempts to keep the overall target of 9 bands to 0dB, the dynamics of drums/bass and other sounds are still present and preserved.
the AGC and MB1 was calibrated using white noise in a manner where the sustained RMS output level from 1Khz to 16Khz from the AGC would be exactly the same RMS level output from MB1 from 1Khz to 16Khz in order to keep the dynamics of common audio like music and talk and let the clipper do its job for those sounds that peak above the average RMS calibrated target of 0db, this gives the illusion of dynamics to the human ear.
i did attach my STS setting for Auto EQ, AGC and MB1 to provide better insight and understanding of my use and to my comment and suggestion about Auto EQ, why i use it in its current configuration and for what reason.
it does do an excellent job for my purposes and reason but as a minimum, there should be an adjustment for the audio gate since it appears to be hard-coded in without any adjustment at all, that would significantly reduce the slight "wah-wah" effect that is heard at low volume audio frequency changes since the gate moves slowly as a result.
i hope my explanation provides a better understanding of my suggestions for ST, think of Auto EQ like a 9-band AGC.
thanks !


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