Latency issues while tracking. no plugs or midi.

[doubtful guest]

Hi Duc folks, I have several protools 8 cs2 sessions that have major latency issues and I'm trying to narrow down the possible causes. Both problems have been repeatable on different sessions, I am not recording through plugins or using midi or VI's.

My problems are:
1.track offsets on recorded tracks
2.Audible delay(slapback) on throughput monitoring while recording or listening through record enabled tracks.

First Problem- While tracking I have had tracks recorded with an offset, tracks have been recorded either 1320 samples early, 100 samples late, on time, or 1320 samples late. Initially I was not tracking with ADC on since I usually keep it off while tracking basics. I'm not using midi or VIs. I did try turning ADC on to see if that would help.
One session had a UAD2 reverb plugin on an aux return and any overdubs are either 1320 samples early or 1320 samples late. I removed the UAD2 plugin from the session and overdubs were then 1320 samples late. If I turn on ADC the overdub is correct and if I turn it off it goes back to 100 samples late.
I've created a new session and then had a 1320 sample offset, with no plugins or anything added. I believe some of the sessions with ADC on also started having offsets after recording ok for a while.


The second problem, while recording or monitoring through record enabled tracks I'm occasionally getting a delay. It sounds like a slap back delay, about the same as if you were using an LE system on a large buffer. I have been able to fix the delay by turning on or toggling ADC. After turning ADC on, I can turn it off and the delay is gone. I think deleting the IO setup has also lowered or changed the delay.

Doing a basic loop back test on a new session with no plugins, I'm sending a recorded click out one channel and back into another. If ADC is not enabled I get a 1320 sample offset late. Is this normal?
I enabled ADC with IO comp and the loopback is now recorded in the correct place. Great! What is weird is the throughput audio delay seems to be much lower with ADC on. If I solo the recorded click and the loopback click being recorded with ADC on, it sounds phasey as you'd expect. If I turn ADC off there is an audible delay, it sounds like double clicks.

Any ideas?
Does this sound like corrupt session data, prefs, I/O setup?
Could the UAD2 card be affecting system latency even if no plugins are on the session?

I'm running protools 8cs2 HD3 on a 2x2.8 quad-core mac, os 10.5.6, with "aurora lynx" converters/cards and a UAD2 card installed.

[doubtful guest]

Is anyone using UAD2 cards with Protools 8?

Is there anything that can cause latency or track offsets if the ADC is turned off?

I'm wondering if the UAD2 card has corrupted the delay compensation somehow? Is that possible?

I've never had latency on an HD system in the past and am having some difficulty finding the cause.

thanks!

[The Egg]

Are you sure there's no plug on the master track? I had the same issue and found that the limiter on the master was inadvertantly left on, causing a slapback type delay.

[DigiTechSupt]

I'm wondering if the UAD2 card has corrupted the delay compensation somehow? Is that possible?

Corrupted it? Possibly. Do you have any of those plug-ins in the session, or had them in the session at any point? Does a new session (not based off a template) exhibit the same problems?

I know UAD cards have some serious latency and some have reported that ADC can't compensate for it all...

[doubtful guest]

Hi, there was no plugin on the master track.

The session I first noticed the problem had one uad reverb plugin on the session on an aux return.

I made a fresh session with no plugins for the test and was still having the latency and track offsets.

In the test session when I sent a recorded click out one output and back another it was recorded 1320 samples early.

Is there anything that could cause this?

I've had offsets of 5-100 samples using different outboard converters etc but I never seen this much before.

thanks!

[zakco]

Originally Posted by DigiTechSupt

I know UAD cards have some serious latency and some have reported that ADC can't compensate for it all...

It's not just uad plugs. You should see what PSP vintage warmer does on an aux . Blaming the 3rd party plugs is a total cop out.

The problem lies with PT and its upper limit on ADC. I would be REALLY happy if that limitation could be done away with. Use whatever resources needed, DSP or host, I don't care, just give us ADC that works no matter what you throw at it...

Sorry for the OT rant, I couldn't help myself...

[doubtful guest]

Yes, I know of some of the limitations of ADC in it's current form...

To be clear on this issue...

I did not have ADC on and the basic tracks and overdubs were being recorded in the wrong place.

There was a monitoring delay(very short) on all tracks on the original session with a reverb plugin in use.

The new session with no plugins also had the tracks recorded in the wrong place(either 1320 samples early or 1320 samples late) and the monitoring delay.

On the new session, I enabled ADC and the tracks recorded fine. I then disabled the ADC and the tracks/overdubs were recorded 100 samples late. Which is what you should expect with no ADC, right?

I'm not totally sure this is related to the previous session with a reverb plugin. Maybe you can't record with ADC off in protools 8? Has this been tested?