64 Tracks on MIX PLUS?

[Raven]

Hi Steve,
I get 32 tracks on a single 9GB, 10,000 rpm Avid Drive. Should I not get 64 tracks on two of these drives connected to an ATTO? Will it help to use a dual channel SCSI card?
I know the installation guide says u should have 4 drives to get 64 tracks.If that is mandatory can these 4 drives be 4 GB each and of what speed should they be?
Thanks

[Steve Rosenthal]

You'll be able to acheive 64 tracks with two drives, depending on the edit density of the material you're working on. Our recommendation of 4 drives is based on being able to playback 64 tracks of audio with an edit density of at least .500ms edits with 30ms crossfades without a DAE -9073 error.

Dual-channel cards are particularly helpful with the 4 drive configurations because you can place two drives on each channel. This lowers your disconnect/reconnect overhead on the SCSI bus which gives you better performance.

It sort of depends on the kind of work you do. Of course, you can always start out with two drives and if your performance isn't where you need it, just add more.

Drives can be pertty much any capacity you desire. That's all going to depend on the length of material you typically create. But there really isn't a restriction.

I hope this answers your questions.



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--Steve Rosenthal, Digidesign ETS

[Raven]

Hi Steve,
That does answer my doubts. Very clear. Thanks a ton.

[Sanctuary]

I'm running a pro tools 24 mix system. I have an atto and two 18 gig cheetahs. I have them on two channels with the express pci dc.
Why can't I get more than 16 tracks on one drive in 24 bit? Why can't I get more than 32 tracks by splitting between two drives?
What can Raid technology do to help my performance? Is there someone who can call me and walk me through this. Do I need another card to get more voices? Is my system limited to 32 voices at 24 bit unless I get another mix card? All these questions are flying through my brain. Research is difficult when you get to this level. My salesman from guitar center was really no help. Please post more on this topic.

[Steve Rosenthal]

Sanctuary,

Clear this up for me: Are you saying you can't get more than 16 tracks from a single drive? Or are you curious whether or not it's possible?

Your Mix card will give you 64 voices, but you need to set that option in the Playback Engine dialog. Otherwise, the default is 32 voices.

Software RAID (striping) doesn't work well with Pro Tools because it is tuned more for single stream, large data transfers. Pro Tools is managing multiple streams of data, and has disk scheduler code that optimizes those transfers. RAID will essentially undo our optimization and re-optimize it for striping, which incurs additional CPU overhead. This can lead to less than desirable performance. Also, Pro Tools is more dependent on the access times of the drives than the overall SCSI throughput, while RAID is really optimized for maximum throughput.

I hope this begins to answer your questions, but keep them coming.



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--Steve Rosenthal, Digidesign ETS

[MightySlim]

this is sanctuary. thanks steve for the tip on gettting 64 voices but the question still stands why can't I get more than 16 tracks running from or to a single drive is there some way of making the drives read faster. whenever i try to record more than 16 tracks(eight at a time through a locked 888 to one drive in 24 bit I get an error message drives to slow or fragmented. The drives are brand new and I used FSB to format the drive. So I think my data transmission rate is two slow. But I've got two cheetahs and an atto isn't this fast enough? get me 64 tracks in 24 bit and I'll love you forever

[Steve Rosenthal]

Okay, now I understand. You're not able to get more than 16 tracks.

What's your DAE Playback buffer setting? If it's 0 or 1 this might be your problem. Try setting it to 2.

Also, check your extensions folder. If the ATTO ExpressPro Tools INIT is installed, that's your culprit. Remove it and you should be okay.

--Steve Rosenthal, Digidesign ETS