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-   -   Latency and software glitches on a powerful system? (http://duc.avid.com/showthread.php?t=401255)

malawar 09-28-2018 02:00 AM

Latency and software glitches on a powerful system?
I'm running this session and facing a few problems which I've listed below. I can't figure out if it's a hardware or software issue. I've also listed some of the things I think are causing or resulted in the problem. I've leaning towards it being a software issue since I compared this session to a similar session and and the other session works fine. I hope someone can go over the information I've provided below and maybe help me resolve this or optimize my system better.

1) Latency when on record-arm or input-monitor even with low buffer.
2) MIDI region first notes on bar disappear
3) While looping a section, I hear the last notes of the previous bar; although they're not in the selection. I've also

What I think is causing the problems:
1) Audio is recalled from back up copy on my external drive rather than being saved in the "clips" and recalled from the internal hard drive.
2) Group-moved everything to an earlier spot in the editing window (including meter changes and markers)
3) Too many instruments/plugins (although the other session has more or less the same)

System Specs:
Please see signature for details.

Session Info:
48 kHz
24 bit
System Delay: 7757 samples (2319 in other session I compared to)

Playback Engine (I've tried all the different combinations here):
128 samples
1 GB Cache

System Usage:
CPU approximately 40% total on both sessions
Disk 0%
Disk Cache 12%
Memory 15%
Voices 30/256
HDX Card has quite a few here all over 50%

Failed attempts to resolve the issue:
1) reduce buffer size to 64 samples
2) dedicate thunderbolt bus on mac to HDX card
3) go over the system optimization document on Avid website
4) run all possible plugins on DSP
5) free space on Mac (98GB free from 256)
6) run session on Mac instead of external HD
7) "save copy in" to create a new version of the session

Sorry about the heavy post, I tried to add as many details as I could, I'm still an amateur on Pro Tools and might not understand a lot of the technical aspects of the software.

Looking forward to your responses!



YYR123 09-29-2018 12:03 AM

Re: Latency and software glitches on a powerful system?
Well......this does sound like a mystery

You didn’t mention your Hard drive types but since it’s fine with the other session I wouldn’t imagine it was that.

I am guessing that it is related to midi latency, b/c that is the only latency not accounted for with the HDX card.

Make all midi tracks inactive, reboot the computer, restart PT....check your system....what happens when trying to record ?

Actually just thought of something else——PT used to have a big problem with routing aux tracks to aux tracks to other aux tracks

Check your routing and make sure it’s the simplest it can be....make in active any aux tracks more than 2 levels deep.

Restart PT and try to record again.


malawar 09-29-2018 11:24 AM

Re: Latency and software glitches on a powerful system?
Thanks for the response!

I was going over the forums and came across a thread that provided some insight on problem 1. There was something really weird happening with the AUX/bus tracks like you mentioned!

I've provided a brief explanation on my workflow to provide a full picture.


I group audio and midi instruments to create buses which go to my 8816 summing mixer. For example, Guitars > Stereo Bus with plugins > Output 5-6 on 8816 > monitors.

I ran a bunch of tests on the routing of those bus tracks to test latency and the results were very weird.


A) All plugins/instruments active. Guitar > 8816 = No Latency.
B) All plugins/instruments active. Guitar > Bus with no plugins > 8816 = Latency
C) All plugins/instruments deactivated. Guitar > Bus with no plugins > 8816 = No Latency

What's odd is that the other session has more or less the same exact setup but I don't get this "aux/bus delay".

As for the 2nd and 3rd problems I've listed relating to MIDI and the loop. I still have no idea what's causing them. I have weird shadows between the MIDI clips on my edit window.

YYR123 10-02-2018 08:32 AM

Re: Latency and software glitches on a powerful system?
I would definately send this into the support guys. If you are running 2018.7 then you probably have a support contract.

email those guys and provide the details, they were always really good help to me.

I agree that is not what i would have expected with my aux's and ADC.

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