Dealing with external ADAT converter latency

[Phil O'Keefe]

I'm using an external ADAT converter to increase the input count on my Carbon setup, and running external mic preamps into that.

The ADAT converter I am currently using has 1.46 ms of delay at 44.1 kHz. What is "best practice" for dealing with this converter latency? Just nudge the tracks earlier by 1.46 ms after a recording pass? Any advice and suggestions are welcomed. Thanks!

I'm running Pro Tools Ultimate 2021.12, PT Carbon, Mac mini M1, 16GB, MacOS 12.1 (Monterey)

[Darryl Ramm]

Sadly your best route is Nudge-o-Matic wetware... folks have asked for configurable delay options in the past... nothing happened AFAIK.

[JFreak]

Doesn't carbon have that automatic latency compensation on IO setup?

[BScout]

Originally Posted by JFreak

Doesn't carbon have that automatic latency compensation on IO setup?

It only compensates for its own hardware.
It doesn't compensate for devices attached (which add additional latency.)

To the OP, you can use user offsets (per track) for latency but it gets messy. It's easier to set a nudge value and then nudge post-record.

For inserts, you can compensate the round trip in I/O. There's been a long standing request to make that sample based (so changing sample rates, you don't have to correct) but that's not been implemented yet.

[martthie_08]

thanks for raising awareness on this issue,
to be honest I never thought of that up until now.

I think the most elegant way to deal with this would be to use a plugin that can provide a negative timing offset on the ADAT input tracks, like Precision Time Align from Eventide for example.

It would be of course much better if ProTools allowed you to enter a user offset for recorded tracks on ADAT inputs - although I image that would get really messy with things like Destructive / Punch record.

And to the previous poster: YES, PLEASE AVID add sample based I/O offsets and PLEASE rework and update the I/O Plugin while you are at it - it could really use a visual indication for clip overs and input/output levels.

[Darryl Ramm]

Originally Posted by martthie_08

I think the most elegant way to deal with this would be to use a plugin that can provide a negative timing offset on the ADAT input tracks, like Precision Time Align from Eventide for example.

I would think Precision Time Align would be awful here. Presumably folks got Carbon because they care about low latency and tracking though HDX plugs, Precision Time Align adds something around 500 samples of latency (at least at 48 kHz) and then does negative values by reporting different delay comp values to Pro Tools and lets Pro Tools time align stuff using it's standard delay comp. It's the last thing you want on a live input.

Or are you thinking workflows where the Precision Time Align plugin is made inactive during tracking and then activated during mixing? That still seems cumbersome to me, but so is nudging by hand.

I'm waiting for a Tardis plugin to do this properly, and that might well happen before Avid ever gets to supporting configurable conversion time in Pro Tools. :-O

[JDubz70]

Hi Phil,

Have you tried turning off Auto Low-Latency in Pro Tools (Blue Mode)?

Here's a good article describing it:

https://www.puremix.net/blog/underst...pensation.html

[I]Pro Tools has a feature called "Auto Low Latency" that is usually ON by default. The idea behind this is that, if you put an audio track in input monitoring and/or recording mode, you will want to record something to it. And if this happens from a real source (e.g. your guitar player needs to record an overdub), Pro Tools assumes you will want the least possible latency to make sure the guitar player can hear what she's playing (yes, she) in time with her performance. "Auto Low Latency" makes sure that the Automatic Delay Compensation rule is broken for tracks that are put in input monitoring and/or arm record mode (green "I" or red dot turned on).

Most of the time this is what you want (especially if the session has lots of plug-ins already) but in this case we don't. We might use this technique to bounce a track into another, and it's paramount that ADC is maintained so we can monitor correctly and commit to the print.

To fix this, we head over to the "delay compensation" pane, at the bottom of that audio track (make sure you have "Delay Compensation" turned on in the "View > Mix Window" menu, to see it). The three fields indicate, from top to bottom:

the total delay, in samples, of that track
the user offset, in samples, of that track (if any)
the total compensation, in samples, of that track, required to equal the delay of the slowest track in the session

normally these fields are all green, but in Pro Tools they can be orange to highlight the slowest track in the session. If they are red, it means the track is not being compensated correctly. Each DAW has a maximum of samples it can compensate.

To turn off "Auto Low Latency" mode for a given track, we right-click on the third, lowest-field of the Delay Compensation Pane, then click on "Auto Low Latency OFF". The compensation field will now look blue to let you know that Low Latency mode is disabled for that track.

Best,

John Whitcore
Sr. Principal Product Manager - Pro Tools Hardware
[email protected]

[its2loud]

Isn’t there a keyboard shortcut for this as well?