Session Template/ Sample Rate Issue

[Iain Graham]

Hey, has anyone had a session created from a template run at a sample rate different to the sample rate of the template? In other words, at least one song on the last 3 albums I've started recording have ended up being 44.1k sessions when they've been created from a template that had a 48k sampling rate.

I've been creating at least 10 songs an album from the same template session (new one for each album) and at least one of the sessions has ended up at a different sample rate.

This becomes a problem because we clock our system from a MOTU Midi Timepiece, so when a mix is bounced outta the session it then runs at the wrong sample rate.

At no time have I made an effort or been given an option to change the sample rate when I've been creating the sessions and the rest of the sessions for the album have been left at the original sessions samplle rate.

The system I'm using is a D24 Mix+, on a G4 mirror door (not sure of the model). We've got 2 888|24s and a MOTU MTP. we're on OS X 10.3.4 (i think) with 6.4.1 cs 1. The problem has occured before we moved up from OS 9 tho.

I create a template by creating a new session in the usual way, cloe the session, get info for the file and make it a stationary pad.

Anyone got any ideas?


Iain

[Natural Sound]

This can happen if you've given the MTPav the job of being the master clock.
Within the MTP you can set the clock to either 44.1 or 48. The PT interfaces are then slaves to that clock. In which case the sample rate of your PT session is irrelevant. (it's only valid when PT is the master clock)
Sounds like someone inadvertantly switched the MTP sample rate. Or sometimes (at least in our case) every once in awhile, settings change on their own.Check the Clockworks Pgm for all your MTP settings.
hope this helps

[Iain Graham]

That's not it dude, the sample rate on the MTP stayed constant (48k), but one of the sessions created from the template switched to running at 44.1 even tho the template was a 48k session. The session is still running at, and sampled at, 48k but PT thinks it's a 44.1k session. When it's played back at 44.1 it's slowed down, as you'd expect. Also, when a mix is bounced out of the session, it runs at the wrong speed because pro tools thinks it's running at 44.1k.

We have had visiting engineers make the mistake of running the MTP at a different rate from the session without realising, but my problem comes from thinking I'm creating a session from a template that is running at 48k and having one out of the ten sessions I created from the template running at 44.1.

The MTP and the template session are running at the same sample rate. One of the sessions created from the template flips to a different sample rate, in other words.

Cheers anyway,

Iain

[Natural Sound]

Yiikes ! Sounds like you've unleashed something evil.
So you're saying that the files are 48K, but when you hit playback, it plays slow at the 44.1 speed?
Very wierd. I guess you're thankful it was only 1 out of the 10.
I guess that also means you wouldn't be able to do any overdubs correct? Since everything would be playing back just slightly slower.
Have you tried Importing the session data to a fresh copy of the template?
Or failing that, create a brand new session, and import the session data to that.
In the meantime, I would blame it on a glitch in the space/time continuum.

[Iain Graham]

Not quite, what I've ended up with is a 44.1k session, but everything has been tracked with a 48k sample rate. If I turn off the MTP and let Pro Tools clock the session, everything plays back slowly. If I leave the MTP on at 48k everything plays back at the right pitch. If I drop the MTP to 44.1k to match the session settings I get the drop in pitch again.

When you then bounce a mix out, Pro Tools thinks it's a 44.1k file and the mix plays back slowed down. I know there are ways round this, but I shouldn't have to do that.

As I've said, the template session and every other session are 48k, it just seems to be one session that ends up at 44.1k without any input from myself. This session is grown from the same template as everything else.

My main concern is that the easiest way to print the mix is to our Marantz CD burner but that means one mix on the album is going to mastering at 16/44.1/interleaved while the rest of the files are 24/48/split. The Marantz has sample rate conversion. My boss masters in Pro Tools (not in the same room!), and that's how he asks for the files.

I'm aware of barbabatch. May have to buy it.

Anyone else got any ideas?

Iain

[Iain Graham]

OK, so I've found another problem that this thing creates. Because auto-tune is sample-rate dependant, it pitches everything to the wrong note when it's been opened in a session that has been clocked at the wrong rate. i.e. the session is set at 44.1k, so auto-tune opens at 44.1k, but the session is clocked at 48k by the MTP, so auto-tune pitches everything (down, i think, can't remember, just sacked it straight away).

Anyone have a solution to this part of it? 4 fiddles, flute, and a 3 piece horn section kinda need a bit of tuning help.

I don't want to have to bounce everything out and edit the files with barbabatch or something, then import them into a new session.

Iain

[DigiTechSupt]

Hi,

If you recorded the session clocked externally to the wrong sample rate you can use DigiBase to correct this . All you have to do is find the audio files in question, scroll over to the sample rate field, and type in the "correct" sample rate (the one they were actually clocked to during recording).

Also, there is another workaround that may be faster and simpler, particularly if there are a ton of audio files to modify:

Open a New Session at the "correct" sample rate, then do Import Session Data and select the session in question. Make sure to choose "Copy from source media" and "Apply SRC", but then change the Source sample rate to the "correct" sample rate (this will make it look like your "converting" from 48k to 48k (for instance) which may seem counterintuitive. In reality all you really are doing is changing the sample rate tag on the audio files, so you definitely don't want any resampling to happen.
Thanks,
Digidesign Tech Support

[Iain Graham]

Great, thanks for the response. I've now got a solution to my problem.
Any idea why the sample rate of the session is changing?

As I said in the first post, I've been creating sessions from a template. All but one of the sessions created for an album have kept the sample rate from the template (which matches the sample rate of our MTP), but one of them has changed it's sample rate without any user input. I've created template sessions for 3 different albums that I've noticed this happen on.

Having a workaround makes it much less of a problem but I'd still like to know whay it's happening.

Cheers,

Iain