Personally, I wouldn't do it... Laptops just don't have the power to handle it. If you run each thing (disc, interface, etc..) on a different firewire bus, you may have a chance, but it will be tough. The Firewire bus just won't have enough to be stable at that many tracks with everything else that will be happening on a live recording.

--Ben

First of all, we are talking a modern laptop. Older boxes, well, they are slower.

I run 24 channels on a laptop (Vaio with Pentium M) without any problems generally. Goes to the built-in 4.200 rpm disk. RME Digiface + pcmcia card. Samplitude shows low single numbers for disc load, so it does not seem that the limiting factor is there.

My guess is that you should be able to run dual Firewire cards on one firewire connection. 8 ch analog on each + 2x8 channels on lightpipe. Limited to 48kHz sampling frequency max, but if you are like me that is not any real problem.

As you already have one fireface, you might be able to borrow another one and test for yourself. A basic performance test could be done by cross connecting lightpipe out from the Firewire to lightpipe in and test the recording process. If you crossconnect between the two units you could clock from the lightpipe cable. Think you will need four litghtpipes then. In the final setup of course you have to look closely on word-clock distribution and such, but there is nothing new there. There are quite a few devices on the market with lightpipe out, alternatively there are conversions from AES to lightpipe (ex: RME ADI-4)

If my hunch is right I think that processor speed is probably the limiting factor. That much input takes quite a bit of interrupt handling which can be a burden on the processor. Memory is seldom a problem in simply tracking. Disk speed can of course be the limit, but 48kHz x 48 channels x 24 bits is about 56 million bits per second, about a quarter of disc capacity. I would avoid having a hard disk on the same channel of firewire with the sound cards if possible.

I would still think not do it with a laptop if avoidable. Laptops tend to have all kinds of interesting problems and can stop from the most odd reasons. Generally without warning and when it matters the most. If at all possible I would try to have at least two recording systems running in parallell. The cost of this might be very low compared to the cost of the people on the stage. It is your choice of course, and I do run a laptop myself. But then I seldom bet much pay for doing the recordings.

Gunnar

PowerBook G4 1,5 15"
1.5 Go RAM
+
Motu Traveler soundcard
+
various preamps and microphones...

I'm planning to record a jazz band on saturday night.
It's the first time I do multitracking.

Drums (3 mics)
Piano (2 mics)
Sax (1 mic)
Bass&doublebass (1 mic)
Singer (1 mic)

Will do that on 8 tracks, and the challenge is that the laptop will provide a mix for the audience with the sound of the vocal & piano.
This is in a small room/venue/bar.

I am far from the 48 tracks you mentioned, but I really hope this will work.

:wink:

hey !

I'v recorded that show onto 8 tracks!
no trouble.

this Motu traveler is fantastic!

i think the most stable solution would be a magma pcmcia expansion chassis : http://www.mobl.com/expansion/products/cardbus_expansion/2slot/index.html

pcmcia is still superior to firewire

equip that with two of these : Link removed they have additional processing power onboard....

and then rack up six of these : Link removed

and last add a firewire 800 harddisk for storage (by the way the powerbook only has ONE firewire bus!!! that's 800megabit for both firewire ports!!)

then you would have the greatest laptop setup on earth..... 8-) 8)

or if you're on a budget leave the laptop at home and buy two of these.... http://www.alesis.com/product.php?id=1

(works and sounds fine.... i tried two synced)

good luck!

Sure it's possible, check out the test Sweetwater did with Motu interfaces.
http://www.sweetwater.com/feature/motu/

Hell they were able record 80 tracks with a mini.

8)

any idea of when they'll be publishing the spreadsheet of results?
I wonder well they fare with Logic Pro 7?

Bob Lentini the SAWstudio developer has recorded an album for the Lon Bronson Band on his laptop at http://lonbronson.com/livecd.html The result is very good so a laptop can be used.

SAW has a live mode which is very powerful. More videos are at http://www.sawstudio.com/index_flash.htm