Help a video guy understand audio hardware

[CubaMark]

I'm on the equipment purchase committee of a small artist-run centre. We are primarily a video house (Beta + other tape format, AVID Xpress and Composer, just purchased two Final Cut Pro systems).

Next month we will be purchasing a Mac G4-based ProTools Mix Core system. Still hashing out the details, but there is one thing that I just don't "get".

Why do we need 15,000 rpm Cheetah SCSI drives (or equivalent)?

Our existing video cutting stations, which combine video and audio, don't require hard drives of that speed...

Thanks in advance,
Mark

[Barnabas]

I'm guessing that it's because in PT we are listening to 64 sound files at the same time. If there are lots of edits in a short amount of time, then the hard drive has to work real fast to keep up. I'm an audio guy who just started learning video editing with Final Cut Pro, so I'm looking at this from the other direction. FCP work fine with the ATA drive that came with my G4.

Lots of PT users are starting to use fast Firewire drives instead of SCSI. If you are not mixing more than 24 tracks and have a medium density of edits, you should be able to use Firewire drives or even fast ATA drives. See Digidesign's position on Firewire drives at http://www.digidesign.com/compato/firewire.html

I've heard that you need to defragment non-SCSI drives more often.

I have the Cheetah SCSI drives and have never had a problem, even when they are 95% full and heavily fragmented.

[CubaMark]

Thanks for your thoughts, though I still don't "get" it.

I teach digital video on an AVID Media Composer, and those drives (slower than the Cheetah's) are more than capable of handling video and audio simultaneously, including dealing with complex timelines of short segments over multiple tracks.

We're just trying to economize here... 36 gig "fast" audio media drives are rather rich, compared to 80 gig ATA drive costs.

Hmmmmm.

[Park Seward]

Pro Tools TDM Hard Drive Minimum Requirements

To provide full 64 track, 24 bit, 48 kHz performance a TDM Pro Tools system must include at least two hard drives, minimum, three recommended. For 64 track sessions that have substantial edit densities (such as one edit every third of a second across 64 voices) or large amounts of crossfades, up to four drives may be required, allocated with 16 tracks per drive and two drives per SCSI channel. Additionally, these drives must meet the following requirements:

Minimum Drive Requirements

*

SCSI interface: Wide single-ended or low-voltage differential (LVD or Ultra 160)

Disk drive rotational speed: 7200 RPM or faster

Buffer Size: 512K or larger

Drives must be dedicated for audio (internal or external)

Mac OS file system: HFS or HFS+. Drives should be initialized with ATTO ExpressPro Tools v2.3.2. If using non-ATTO ExpressPro-Tools initialized drives, click here for options.

IDE/ATA Hard Drives

IDE/ATA drives meeting the requirements at this link are now qualified for 32 track performance with Mac TDM systems.


So if you want the very best with 1/3 of a second over 64 voices (that's a lot) then you could get SCSI for quaranteed performance. However, the IDE drives can handle 32 tracks per drive. Seems like the cheapest way to go and it will probably meet all your needs.