Delay with busses

[jasonmiller0607]

@daeron80... yes, you are correct. No one has answered why THERE IS LATENCY WHEN I USE INTERNAL BUSSES. I understand there is latency with converters. I understand there is additional latency when using Firewire or USB ports. I understand Pro Tools cannot automatically compensate for 3rd party converters. I also understand that a lot of plugins cause various amounts of latency.

Why is there additional latency when I route audio through and aux track to an audio track?!?!

And while I'm at it... why can't I simply contact Avid support anymore and just ask them?

[carlone]

This is a user forum.
You wanna reach support directly you have to get a support ticket.

[zedhed]

Originally Posted by carlone

For the record I get 0 delay when routing and audio track to an Aux. This is with an hd native system.

As others have said - I'd look to your drivers and interface.

0 Delay for me too...and I'm on an LE system.

[daeron80]

Originally Posted by jasonmiller0607

No one has answered why THERE IS LATENCY WHEN I USE INTERNAL BUSSES.

I seriously doubt that Avid tech support has the foggiest idea. I would think you'd have to talk to somebody who's deeply involved in the design and/or programming to get an answer with any degree of certainty to it.

It's especially strange since even in past versions, when delay compensation was not yet a feature, no delay was produced by using a Send to route audio to an Aux. E.i., an Audio track going to main outs + sending to an Aux track through a bus, the Aux track going to main outs = totally in phase. So if it can (and long has been able to) route it through a Send with no delay, why can't it do it now when routing through the track outs? I guess it has been compensating for bus delays for a long time, just not plug-in delays?

[Chris Watkins]

Right, so, something is a foot here and I ask again, did you try a DIFFERENT DRIVER YET OR ARE YOU STILL COMPLAINING WITHOUT TRYING DIFFERENT THINGS?

#1. On my box; I get no delay 0. none.
#2. I can offset compensation in every version of PT I've ever worked with,
it has set it aside from things like cubase because of this fact, it has auto + manual, not just Auto_that_screws_you.

#3. I will make an observation that what looks like what is happening is the following:
For some reason; for session compatibility reasons PT things you have a PTHD session with a traditional HD aux buss in the session and is compensating for a TDM bus delay @ X buffers. This is why I wanted the driver swapped out, especially a driver that is known to be stereo centric; because for session compatibility reasons it's delaying the busses.
Also; as I do not believe I see it stated clearly; did not turning off ADC remove it? and as I stated, what about changing the delay to equal comp, etc, like normally done when a external FX was wrong with a TDM delay?


So, again, the only time PDC should add a delay compensation is when two unequal busses do not equal the same so that the master is the same and thus on the master it's not needed.

[jasonmiller0607]

@carlone, @daeron80 My whole point was that Avid Tech Support and support tickets no longer exist. Seems the only way I can contact Avid is if I buy an $80 support code that's good for one phone call. If I'm wrong, someone please correct me... but that just seems like some of the worst customer service ever. I mean... I know companies that have pretty bad customer service, but I can at least contact them by email or phone.

@Chris Watkins... Dude. It's not a driver. I have the correct driver for the Lynx, I have the correct diver for my M-Audio 2626, and other people have posted with a similar problem on their different systems. This problem is not hardware-based.

So, to confirm, on your system you get no delay. What is your system? If you haven't already, please create the same session that a couple of us have already. New session. Create one aux track and one audio track. The input of the aux should be from your interface. The output should be a bus. Make the input of the audio track that bus. If you toggle record on an off, the delay should appear and go away. (H/W Buffer: 128, sample rate 44.1kHz)

Here's another test for everyone reading. I'd love it if an LE user could do this. Create a new session. One audio track, then an aux track, then an audio track. Put your grid into min/sec. Then, highlight one second and audiosuite a 1k tone. Route the output of that track to the aux, then route the output of the aux to the other audio track. Highlight your selection and record it to the second audio track. Zoom in and see if it's delayed. Try it with several buffer settings and with delay compensation on and off. Any differences? To measure the delay you can put your grid into samples mode, tab to transient on each and highlight the difference. The length of your selection with be the amount of delay.

I'll do it on my current system and report some results.

In the name of science!

[daeron80]

@Chris - My system is non-HD as well as non-TDM (plain 9.0.1, 002R) and I get the 200+ sample delay indication on tracks output to buses that are at least potentially routed to hardware outs. Like Jason, I wonder whether you're setting your session up the same way we are. I'd love to see a screenshot of yours set up exactly like ours, nothing in record.

@Jason - LE doesn't show delay compensation because it doesn't have PDC, so that's no good. It has to be PT9.

When you record bussed material to an Audio track, PT is supposed to compensate automatically (even in older versions), so that shouldn't reveal the problem. Maybe the delay could be confirmed by recording something from an analog input that is received through two tracks: an Audio track and an Aux track that is bussed to a second Audio track. Pan the two Audio tracks hard L and R and record the output to a DAT or other external recorder via the analog outs. Then record that back into PT and measure the delay, if any. Unfortunately, I'm going to be very busy for the next three evenings and probably won't have a chance to test that on my home system until Saturday, if then.

[jasonmiller0607]

@daeron80... I know LE doesn't have compensation, and it works differently from TDM systems which is why I want it to be part of the test.

RE: The test... Pro Tools will compensate if you're going straight from an aux to and audio track... but when the source material is not ON the aux (like an instrument) it won't know to compensate for anything. This is why I suggest passing audio THROUGH an aux. Which, is exactly what I am doing in the first place.

[jasonmiller0607]

Also, I'll buy a 6 pack of your choice for the first Avid engineer who comes to this party. Seriously. Please.

[daeron80]

I do the busing record situation you describe above all the time on 7.3.1 LE Mac (with musical or spoken-word material, not an unvarying waveform). There's never any recorded delay unless I'm using heavy plug-ins, regardless of buffer setting. It's sample accurate.