[LAU] hardware: recording voice and acc. guitar

[Pieter Palmers]

Mark Knecht wrote:
> On Wed, May 28, 2008 at 9:06 AM, Pieter Palmers <pieterp at joow.be> wrote:
> <SNIP>
>>> Sounds great, but where can I find a firewire interface that will let me
>>> record 24+ tracks at once. I am in the market for one if my pocket can handle
>>> the cost... (This is in no way related to to USB comparison...)
>> There are none that have 24 preamps. However, there are plenty that can
>> handle +24 channels with the use of external preamps. The magic number
>> seems to be "26", being "8 preamps, 2x ADAT, 1x spdif". Then there are
>> some devices that provide 4x/4x ADAT I/O.
>>
>> I'm only going to give one device name since that's the only one on our
>> supported device list: Focusrite Saffire PRO26.
>>
>> To get a more broad overview of the market I would suggest you look at
>> the offerings from TC Electronic, Presonus and M-Audio too if you look
>> for something like this. I can name at least 5 devices that do 24channel
>> (spdif doesn't count for me) I/O if you have 16channels of external
>> preamp. All at 48k of course.
>>
>> Greets,
>>
>> Pieter
>>
> 
> Or if money is an issue right now he could buy a nice Presouns 8
> channel unit, make sure he likes it, and then add more 8 channel units
> later. Use an external clock generator to sync them and he's in fat
> city. If one unit goes down, power supply dies, XLR connector goes
> bad, he can get it fixed but he still has 16 channels.
You don't even need external sync with the presonus units. They can sync 
to firewire.

> 
> Just an idea,
> Mark
> 
> P.S. - I didn't understand your comment earlier about a globally
> available 1394b clock. I worked on that spec and I just don't remember
> that. Been too long I suppose...

I'm talking about the Cycle Timer Register that is globally available to 
all nodes. It's incremented by the cycle master at 24.576MHz, and all 
nodes have (approximately) the same view of this clock. All audio 
samples transported on the 1394 bus are timestamped relative to this 
cycle timer. This means that every sample has an "absolute" time 
attached, no matter what device it is sent to. This enables the use of 
multiple devices, like you suggest, without any form of external sync. 
It even beats wordclock sync since that only ensures relative sync (same 
rate), but still leaves an ambiguity in the exact absolute time a sample 
should have.

I hope that refreshes things a bit :).

Greets,

Pieter