Mixer internal latency problem

[misterphos]

I've just updated from PT 9 to 12.5.2 (forced by the theft of my old laptop) so apologies if this issue has been raised for earlier updates, but I'm now having trouble with the internal latency of the mixer. I use a lot of dub-style echoes, and like to create a feedback loop by sending the aux channel containing the delay plugin back to itself, instead of using the internal feedback in the plugin. This way I can put EQ and dynamics in the feedback loop and create various interesting effects with automation. This used to work fine in PT 9, and even with a varying tempo I could use a tempo-synced delay to keep the echoes in time. However in PT 12, there seems to be a large latency in the aux send bus or aux channel, around 1000 samples, which makes the echoes go out of time. Delay Compensation doesn't help either way, nor does changing the hardware buffer, and I can't find any other relevant settings to change. Any suggestions on how to minimise this latency? Or failing that, can anyone recommend a delay plugin with built-in EQ and dynamics?

[JFreak]

Welcome to the community.

Did I understand you correctly here; you're having a signal coming in at IN buss and going out to OUT buss, and you're also having a send on that aux channel to IN buss?

I would guess the latency should be the sum of plugin processing plus one sample (due to the deterministic nature of the mixer). If this is not the case, please contact support and explain why you think ADC is not working on your system.

[Darryl Ramm]

Originally Posted by misterphos

I've just updated from PT 9 to 12.5.2 (forced by the theft of my old laptop) so apologies if this issue has been raised for earlier updates, but I'm now having trouble with the internal latency of the mixer. I use a lot of dub-style echoes, and like to create a feedback loop by sending the aux channel containing the delay plugin back to itself, instead of using the internal feedback in the plugin. This way I can put EQ and dynamics in the feedback loop and create various interesting effects with automation. This used to work fine in PT 9, and even with a varying tempo I could use a tempo-synced delay to keep the echoes in time. However in PT 12, there seems to be a large latency in the aux send bus or aux channel, around 1000 samples, which makes the echoes go out of time. Delay Compensation doesn't help either way, nor does changing the hardware buffer, and I can't find any other relevant settings to change. Any suggestions on how to minimise this latency? Or failing that, can anyone recommend a delay plugin with built-in EQ and dynamics?

You are seeing the effect of Pro Tools split IO buffers. With a 1024 sample playback buffer that you cannot change the size of. The playback engine IO buffer size you are adjusting only affects record armed tracks and live aux inputs.

Delay compensation is not going to be able to help when you are feeding back latency in an infinite loop.

[Rich Breen]

What about turning off ADC for the channel you've got the effect on (ctrl-command click the ADC amount)? Would that help?

[Darryl Ramm]

Originally Posted by Rich Breen

What about turning off ADC for the channel you've got the effect on (ctrl-command click the ADC amount)? Would that help?

Unlikely. The latency will be very real and still there.

[misterphos]

Thanks for your replies, all. As Daryl says, it seems to be an internal buffer which causes 1024 samples of latency. I'll contact support and see if they have anything to say about it but I'm not getting my hopes up.