Aux send + enabled sub channel strip, possible bug?

[ChrisG]

Or user error. I had a few drum loops on 3 channels/tracks routed to a sub channel. On that sub channel I used the built-in PSP limiter in the sub channel strip, and a compressor in one of the insert slots. All good so far. I added Classic Verb Pro in one of the aux sends, and set the aux send on the sub channel to the default send value (by double tap). But now everything suddenly sounded really muddy and just wrong. If I disabled the PSPstrip (bypass button) it all sounds as it should, with the aux reverb and the insert compressor in the sub channel. I enabled the PSP sub strip again since I used the limiter in there, and it all went back to sounding like really muddy. To fix it I had to enable the EQ in the sub channel strip, and subsequently all three EQ bands and have them at their default value (zero on everything). Disabling the EQ and it messes up the sound, enabling and re-enable all three EQ bands fixes it. So it seems that the EQ in a PSP sub channel strip affects the aux output on a sub channel somehow, whether the EQ is on or off. The compressor and the limiter units in the sub strip doesn't affect anything (neither having a insert effect). I tried classic verb, classic pro, and the convo verb unit in the aux with the same result.

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So step by step...

Route a channel to a sub channel.

Enable the PSP strip (by pressing the bypass button), turn off all three units and set it all to default values.

Slap some effect in one of the aux slots.

Play back the audio from the sub channel.

Raise the aux send knob on the sub channel to the default send-value by dubble tapping it.

Listen to the audio again, and it should sound really muddy/wrong.

Enable the EQ in the sub channel strip, and subsequently all three EQ bands while playing back and the audio should sound right again.

Alternatively, completely bypass the sub channel PSPstrip by pressing the bypass button and the audio should sound right again.

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I tried all three audio modes, legacy, standard, and multi. Ok, hope I'm making sense here. Is anyone else getting this?

[ChrisG]

I tried enabling aux delay compensations under mixer settings, and that kinda reversed the behavior. With that option enabled the audio is clean, until the EQ is enabled in the sub strip. And to get the audio back to correct freq/level you need to dial/mess around with the EQ quite a bit to find it. Which obviously won't work.


Edit: Just to make it clear, it's not me having dialed in any EQ settings that might effect the audio and make it muddy. It's just that it all seems to be tied to the EQ strip unit in some way (whether it's on or off) when the sub channel PSPstrip is enabled and an aux send is applied to that sub channel.

[Matt W]

Thanks for the info, we're taking a look at your to see if there's a bug there. Have you noticed this happening with Aux effects other than ClassicVerb Pro?

[ChrisG]

Thanks for the info, we're taking a look at your to see if there's a bug there. Have you noticed this happening with Aux effects other than ClassicVerb Pro?

I tried it with Classic verb, Classic verb Pro and the convo reverb so far, on a few different projects. But I'm pretty sure you could put any effect in the aux. It's easy to reproduce.

0. Make sure aux delay compensation is NOT enabled..

1. Create a new project,
2. loop some standard stereo wave file audio/track,
3. route that audio to a sub,
4. put the classic verb in an aux,
5. raise the aux send to 0 db on the sub channel,
6. open the sub channel PSPstrip (EQ, busspressor and limiter should be OFF by this stage),
7. enable the PSPstrip

You should hear a really bad degrade on the audio freq when enabling the strip. Enable the EQ and the 3 bands (they should be set to 0), and the quality comes back up. If you change the aux delay compensation option to "on" in settings, you won't hear any degradation to the audio when enabling the strip. But if you enable the EQ the audio degradation comes back. So something weird with aux delay and the EQ. Anyway should be easy to see/hear if you do the above (unless my system is totally weird here).

[Rim]

OK it looks like this is caused by phase due to latency. It seems Auria isn't compensating channelstrips in the subgroups properly. Of course, disabling/enabling AUX delay compensation is a separate problem. If you plan on mixing the aux send with the original source sent to the aux bus, you'll have potential latency/phase issues if the plugin inserted in the aux bus has any latency.

Also, keep in mind that enabling AUX delay compensation uses a lot of resources.

Thanks for finding this issue. I've added it to my list to fix in 1.12/3.

Rim

[ChrisG]

Great, thanks for finding it so fast and for the fast response. About switching between aux delay compensation, that was just me trying to isolate the problem. I don't use record interfaces etc (which I'm guessing the compensation is primarily for?). Anyway, I was just gonna test out adding some reverb to some drum loops I had made, so no big rush on my part for getting it fixed, I'm just glad you could confirm it so I know it's not just me/my setup!

[Rim]

Not a problem. As far as delay compensation, it's used for mixing in general. What it does is get rid of the latency that plugins use, so you don't have to manually nudge your audio tracks to compensate for it. Auria has delay compensation built in and it's always on for normal tracks. The only one that's switchable is the AUX delay compensation, because using it takes memory/CPU and disk resources, so it's a selectable option.


Rim

[ChrisG]

Well that's one new thing I've learned today. Good to know, thanks again.