Sharing the firewire bus: 2882 <-> audio HD

[Pasfaz]

My old dual G5 just died on me and I'm contemplating buying a brand new iMac (the new quad model).

It seems reasonably priced, looks gorgeous...

The only thing is, I'm a bit worried about the one firewire port. I'd have to share it with the audio recording HD, since the internal HD would have all the virtual instruments, samples etc... and the software).

Any of you have tried this?

Thanks

 

[Markdvc]

I haven't had any bad experiences recording to my 2882 onto a FW drive using a Mac Book Pro - meaning, using the same F/W bus for both audio drive and interface.

In fairness, I usually have the external drive(s) connected to the Mac per S-ATA Adapter, as I do feel that it is just that little bit safer to leave the F/W bus free for the audio interface, but it really should work, lots of people using notebooks rely on this. I would also say that the MH drivers will deal with sharing the bus with a HD better than some others I won't name

kind regards

Mark

 

[Pasfaz]

In fairness, I usually have the external drive(s) connected to the Mac per S-ATA Adapter, as I do feel that it is just that little bit safer to leave the F/W bus free for the audio interface.Mark

Sorry, if not to the FW port, is the S-ATA adapter to your mac book's USB port then?

Another thing: is the 2882's firewire port 400 or 800? Judging from the looks of it, it seems like 400, but I couldn't ascertain that anywhere at the Metric Halo site.

Does that mean it would bring the whole firewire chain's throughput down to 400 (even if the disks themselves are 800)?

I guess I'm a bit confused about this...

 

[Markdvc]

In fairness, I usually have the external drive(s) connected to the Mac per S-ATA Adapter, as I do feel that it is just that little bit safer to leave the F/W bus free for the audio interface.Mark

Sorry, if not to the FW port, is the S-ATA adapter to your mac book's USB port then?

It is a Mac Book Pro, and has a 3/4 express card slot, in which I use this seritek adapter. This unfortunately won't work with a Mac Book, which has no such slot. In fact, wrt the current generation af Apple notebooks, the only one which still has such a slot is the 17". They dropped it from the 15" model.

Another thing: is the 2882's firewire port 400 or 800?

F/W400

Does that mean it would bring the whole firewire chain's throughput down to 400 (even if the disks themselves are 800)?

Yes, I AFAIK it does. That is still 50 MB/Sec, still plenty of bandwidth for most audio purposes.

kind regards

Mark

 

[Pasfaz]

It is a Mac Book Pro, and has a 3/4 express card slot, in which I use this seritek adapter. This unfortunately won't work with a Mac Book, which has no such slot. In fact, wrt the current generation af Apple notebooks, the only one which still has such a slot is the 17". They dropped it from the 15" model.

And nothing like that on the new iMacs either.

0.25 meg/ sec needed to read one stereo 24bit 44.1 track... so 50Meg/sec would theoretically allow 200 stereo tracks to be read, am I right?

Thanks

 

[Allen Rowand]

Another option would be to use a USB drive for your audio recording. USB2 has roughly the same throughput as Firewire, and you don't need the isochronous transfer that FW offers for data recording.

 

[Pasfaz]

Another option would be to use a USB drive for your audio recording. USB2 has roughly the same throughput as Firewire, and you don't need the isochronous transfer that FW offers for data recording.

That's interesting... I haven't heard of USB2 being used that way yet in the studios I know. I see 480 Mbit/sec, sorry would that be the equivalent of 48 meg?

Anyways, I'm gonna run a series of tests in Logic on a macbook, using a high track count project stored on a FW 800 drive, with and without the 2882 in the chain, and I'll post the results here.

 

[mhbj]

USB2 gives 60 MB/s peak performance, but probably doesn't provide that in practice. But using USB2 for the drive is a good option on the iMacs.

As far as FW goes, the key to using a FW800 drive with the MIO is to connect the Computer to the drive via FW800 and then chain the MIO(s) off of the drive or a hub at FW400. As long as you do that, the computer will communicate with the drive at s800 rates and you will get the best performance. If you reverse the order (and connect the drive to the computer through the MIO) then the drive will be forced to communicate at s400.

We have lots of folks that are able to use FW800 drives and the MIO successfully at the same time. Of course, if your needs exceed the available bandwidth, there will be problems. In that case, putting the drive on the USB2 is a good way to go.

 

[Pasfaz]

Test: sharing 2882 - Audio HD on fw bus w/ Logic 9

So I just did a simple test: I hooked up the ole macbook (Core Duo 2.6 w. 2 gig ram) to the 2882, chained to a fw HD on which I had copied the Logic 9 demos.

I must say I'm impressed. All four demos ran flawlessly...

Even the stamp-sized movies were playing along nicely. Only on the busiest two (Lily Allen, and the one from The Killers which has 80+ tracks) did it stop a few times with the message "the audio engine couldn't process in time etc..", but only on the first pass.

When I played them a second time there were no interruptions.

I know those demos don't use any third-party plugs or instruments, but still... I'm more relaxed now about using an iMac for serious studio work.

 

[Logey]

Pasfaz,
Were these demo sessions at 96khz? Did you try putting the 2882 last in the chain as BJ suggested? I'm curious about this exact same setup and it is the only thing I can think of that would keep me from buying a new iMac!
Anyone else with anecdotal track counts for an iMac (or similar) sharing a single FW bus with a 2882 and a FW800 drive?
Thanks,
Logey

 

[Pasfaz]

The demos are in 44.1

I've been enjoying the new setup for a little more than a month now, and it just rocks.

No problems at all sharing the firewire bus between the audio HD and the 2882.

As far as project studio production goes, to me the iMac solution is a no-brainer.

 

[hutzal]

Even if the Mac did have more than 1 FW port, it would be connected to the same internal bus on the computer, so essentially it is the same as daisy chaining the one port.