For how long can I record on a single pass?

[M&Mguy]

Ok, heres the deal.

I want to record a live show at a church. It's 2 sets of 50 minutes each, and 10 to 12 channels at once.

I own an iMac i5 with 16gb or ram and Lion, and a MacBook Pro i7 with 8gb of ram and Lion. I would be recording into a 3tb Lacie Hard drive via Thunderbolt. I'd be using Pro Tools 10.

I just wanted to know for how long can Pro Tools record in one take with that many channels, and which one of my computers would be better for the job.

Thanks for your help

[Drew Mazurek]

Would need bit depth and sample rate to calculate. It's limited by the max file size of the OS AFAIK.

http://www.theaudioarchive.com/TAA_R..._File_Size.htm

This should help.

[joachim]

Assuming Mac OS Extended (HFS+) and 24bit/48KHz and 12 mono channels :
50 min x 2 = 100 min
100 min mono x 10 MB = very roughly 1 GB
12 channels = very roughly 12 GB
no file size limit.

You may test it yourself:
set up the same session in both computers, each with 12 tracks, some bogus input, record enable, hit record, observe system usage on both machines.

[jasonthurley]

I believe the limit is 24 hours as the timeline/timecode will have to repeat at that point, other than that it is based on storage size of the capture drive.

[JFreak]

Drew and Jason are both correct.

The max file size that OS allows is a technical limit that cannot be beaten.
The 24-hour timeline is a technical limit that cannot be beaten.

Then again, of course one must take into account that if you have a spinner (a regular old-fashioned hard drive) it will slow down drastically once you've used 50% capacity. So you need to over-estimate your capacity requirements if you don't want to plan on getting a "hiccup" on the last hour of your recording.

But for what it's worth, you can test this before the gig.

What you want to do is set up the session just like it was the real thing. Record-arm the tracks and hit record+play. Wait for it until your preferred minutes are done. If you're satisfied with just one pass you can go to sleep but if you want to be sure, repeat 3...6 times with exactly same results and you can be pretty sure your system performs just the same the next time you need it.

If you get hiccups, you know that there will be hiccups live as well.

[JFreak]

Originally Posted by joachim

Assuming Mac OS Extended (HFS+) ... no file size limit

Not true.

Every file system has its limits. And the mentioned HFS+ has a limit of 8 exabyte file size.

Granted, you don't very often see files of exabyte range, but still, there is a limit.

[Rich Breen]

Limit will be max WAV file size; about 4GB IIRC, so depends on bit depth and SR.

In any case, you'll be nowhere that in your scenario (2 50 minute sets); Recording 1.5 to 2 hour live shows in PT is a common task. Make sure energy saver prefs are all off, all background tasks are off, spotlight off, hard drives optimized, etc... and you should be fine. If it's really demanding (high sample rate, high track count), splitting the tracks to multiple hard drives will increase liability.


best,
rich

[JFreak]

Originally Posted by Rich Breen

Recording 1.5 to 2 hour live shows in PT is a common task.

Very true. I've done a hundred(ish) live gigs 184 minutes a piece. And that exact time comes from certain standard video tape length :)

[joachim]

Originally Posted by JFreak

Not true.
Every file system has its limits. And the mentioned HFS+ has a limit of 8 exabyte file size.
Granted, you don't very often see files of exabyte range, but still, there is a limit.

Thanks for correcting,
and
for reassuring :

Originally Posted by joachim

You may test it yourself:
set up the same session in both computers, each with 12 tracks, some bogus input, record enable, hit record, observe system usage on both machines.

Originally Posted by JFreak

But for what it's worth, you can test this before the gig.
What you want to do is set up the session just like it was the real thing. Record-arm the tracks and hit record+play. Wait for it until your preferred minutes are done.