Logic Pro 9 Stability of logic for very large live recordings


New Member
Evenin' all :)

While digging around for some feedback, I came across this group and feel I could probably get some good opinions here. I've been a logic 8 user for about 5 years now, but that's mainly for mixing and the occasional sound design work. However, I've never really tracked anything of significance in it.

Currently running a PT 7.x HD3 rig to track our live shows (about 86 inputs) and it has been running fine. However, we are entertaining the idea of switching over to a Digico system that will require the use of MADI ports for output. Also, we are looking to start recording at 96kHz up from 48kHz. I've checked out some interfaces that will talk to the current PT setup and I can make it happen with 84 inputs the way we are now. Down the road if we need more, things start to get pricey again hah.

Since this box will be doing nothing but tracking, I thought about removing the HD cards and tossing in 2 SSL madixtreme 128's to give myself a total of 112 possible inputs @ 96kHz. If I need more down the road, a 3rd card would put me at 168.

So...has anyone here tracked these number of inputs (or close)? I can give the box a break during the set change, but being able to run non-stop for 3-4 hours is definitely a must. I know one thing I do like in PT is that I can assign each track a specified recording location. I like to break the total track count into thirds so I can span the recordings across 3 drives to help ease the load. At least in my version of Logic 8, I only see a global record folder setting. Anyway, any opinions or advice would be appreciated.

Take Care!
Off the top of my head you would require something close to 30 megabytes a sec or more to get 112 tracks at 96k. That would require a raid at least (Logic doesn't allow you to select what data records where). Then for the 3 hours constant 112 tracks of 96k is 318 meg an hour, so you will need a 4 tb system (I'd go for a 4 drive raid 1tb each or larger, Raid 01) so you are covered with data duplication, have plenty of speed and lots of room to edit later.

I have never tried to do this before myself, at least no more than 48 tracks during a test, but I'm sure if you get a good raid setup, you should be good to go. the next question is how would you get that many tracks into 1 computer at once?

Since Mac Pros only have 4 slots (if you get a cheap video card) you are limited to 72 with an RME Raydat system, unless you buy an expansion chassis, and then you can go higher. 112 means 4 ray dat cards (each card has 36 I/O, so you would need 4 to get 112 tracks), and then you would also require the same number of A/D converters... who knows what that would cost, depending on the converters. If you got say a Lynx 16 channel ADAT system to go into each Raydat, you would need 7.

So it's gonna cost you a fortune anyways, but that said, about 1/2 the price of a Protools system, and I think it will sound fantastic.

Off the top of my head ;-))


New Member
Getting the number of tracks to the machine doesn't appear to be a big problem. The Digico boards have MADI BNC outs...so here's what I was planning for my signal path.

1.Take 4 BNC MADIs out of the board
2. Run into a RME MADI converter which basically converts my BNC to 4 MADI fiber lines
3. Run those 4 lines (28 channels a line) to the SSL MadiXtreme 128 cards PCIe, they have 2 fiber inputs per card. So 1 card gives me 56 channels at 96k
Cost for that setup is around $5k

But like you said, the write speeds are going to be my issue I'm afraid. I track to the internal drives of the mac pro (no problems in the past few years), I'll check this week to see what write speeds are at as I'm pretty sure it's higher than 30mb/s. The drives I track to are WD Caviar Blacks SATA 3.0, 1TB per drive, 7200RPM with a 32MB cache and they have been running like champs.
Edit: I track to drive bays 2,3,4. Never to the system drive in bay 1. I also do a 1-pass Zero write to the drives when I put a new batch in. May not be necessary, but gives me piece of mind.

A typical session at 48kHz ends up being ~130 gigs, so doubling that for 96kHz should put me in the ballpark of ~260gig per show. So even if Im forced to record to one drive, 1TB should provide enough storage. But that is a lot for one drive. Hopefully, Logic uses the RAM as a buffer before it gets written to the drive. I've always been impressed with Logic's system performance, even on my old retired powerbook g4 haha.