Multiple input devices into one computer?

[antichef]

I'm definitely a newb to computer recording, and there a few questions that are on my mind -- I think I know (and don't particularly like) the answer to this one, but I'll ask the question, hoping I'm wrong.

I have a pc and a mac, each has a "sound card" native sound system, and I also have a firewire interface (with 4 inputs that can support 2 stereo tracks), and some odd cable with a quarter inch plug on one end and a usb plug on another, and apparently an embedded converter. Each class of things here, 1) sound card, 2) interface, 3) strange cable, counts as a different sound input/output device on the computers, and this is true for the pc or the mac. This is apparent generally, at the OS level - for instance on the w2k pc, when you adjust volume from double clicking on the little speaker icon in the task tray, you can pick each device and you get all the little sliders, but you can't see all the sliders for more than one device at a time.

Now, take the mac - in Garage Band, I can go to preferences -> Audio/Midi and select exactly one device for each of input and output. I'm interested in the input here - if I select the firewire interface, I get two stereo inputs (for a total of four inputs that I can assign comfortably to two different tracks) - nice, but I'm not able to access the one additional stereo input represented by the sound card (because I deselected it when I picked the interface) and if I have the odd cable plugged in, I can't get to it either (that would be another mono input, I think). On the PC, I see essentially the same scenario with Audacity, and I don't know what the heck I'm doing with Cubase LE, but I'm thinking I'll wind up in the same boat.

Sorry for the extended build-up - there's a newb for you. My question is, can I game this in any way to be able to access all my input devices from the recording software simultaneously? I've got to believe that the hardware would support it, but I see a software limitation that is either at the OS level or at the recording software level (and I'm not sure which) forcing me to choose just one input device.

Now for the speculation -- if it's merely a recording software limitation, then someone (not me ?) could write a "virtual" sound device that bundles the existing OS inputs (and maybe outputs) into one choice that could be picked up by the recording software. If it's an OS limitation, then that's tougher, but maybe still surmountable. If it's a hardware limitation, then that's all she wrote, from my perspective. The other possibility is that there's no real limitation, and I just don't get that.

I'm prepared to be be advised to just do it right and get the interface I really need (or, more accurately, want) for what I'm doing, but I wanted to ask this first, because that's what newbie discussion groups are all about

Anyone with thoughts on this?

 

[DonF]

What you ask for is possible in theory. The main problem with creating a virtual device from multiple hardware units is getting their clocks to run in sync with each other. As accurate as digital clocks are, the drift, even between two seemingly identical units, would be sufficient to make the system unusable.

That's why higher-end A/D convertors have external clock inputs. One master clock is used to drive all the digital devices in the studio, so they all stay in sync with each other.

If you can find some way to lock the various devices together, then your virtual device is a possibility. (Not necessarily in Windows or OS X, though, unless you are into writing your own device drivers.)

Don

 

[Minion]

This is also a Driver limitation as each Device uses a seperate driver but your PC/Mac can only load one driver at a Time for recording....If all of the devices used the same driver you could in theory use all the devices at the same time but then you will run into Sync issues.....

With the ASIO4All Driver (For PC) you can load multiple ASIO Compatible devices into the same program and use them all at the same time but without there being a Master device who"s clock is used by all devices you will run into Problems....


Cheers

 

[Greg_L]

I'm having the same situation. I recently bought a Firepod to replace my US-122. The Firepod is awesome, works great, and gives me 8 simultaneous inputs, but out of greed I wanted to run the US-122 along side of it to get its 2 inputs as well giving me 10 pre-amped XLR inputs. Since one runs via firewire and the other uses USB, surely it should work since they both use cubase. Nope. Won't work. Each device needs its own driver, and I don't see any way around it. They can't be run at the same time.

 

[antichef]

I thought I'd dig this thread up, because I did discover a way to run two devices together on the mac (I'm running OS X 10.4.10), provided they have the same sample rate. Maybe it was added to OS X through an update, because I looked for it before, and I swear it wasn't there:

Applications -> Audio/Midi Setup -> Audio menu -> "Open aggregate device editor", then you can hit the + sign and add an aggregate device, check the boxes for the actual devices that should be included (including the built-in microphone, etc.), pick which one supplies the clock, and there's also a check box to "resample" the device, but I'm not sure what that does -- maybe takes care of the situation where two actual devices have different sample rates? You can rename the new aggregate device by clicking on it. That's pretty much what I was imagining, and I didn't have to write it

I was able to combine my MOTU Traveler and Presonus Inspire, and all the inputs were visible in Logic Express / Garage Band (just numbered, though, so it can be hard to keep straight if there are a lot of them). Haven't tested too much, but everything did seem to be in order.

I guess I'm glad I didn't see this earlier, because I might not have got the Traveler, which really kicks ass. It's great to be able to use the Presonus device again without swapping out, too, because the pres are different, and go well with some of my mics.

 

[Sinistah]

i'm glad i just record vocals.........

analog box/channel strip, A/D converter, PC...

ahh now if a perfect mixdown was as simple as my set-up.........