How to tell number of audio channels exposed to computer over USB?

Question

I would like to record multiple separate channels on my computer. I.e. such that each input in the breakout box is exposed as an separate input to the audio software.

It seems like a lot of breakout boxes mix all inputs down and only expose it as 2 channels(stereo left/right) over USB. I've found a few that seem to imply that they support more, but the nomenclature seems to vary a lot, and reading the technical specifications doesn't clarify things.

For example, I've seen a couple that list "USB 4-in/4-out" which implies it exposes two stereo inputs to the computer(or 4 channels from computer to mixer but I'm not concerned with that). But if the box has more physical inputs than 4, looking at the manual doesn't clarify how you control which inputs get mixed down to the 4 usb channels.

Another device, the http://www.alesis.com/multimix8usb20 states "10-direct outputs to your computer for recording", which implies it gives the computer access to 10 seperate channels to the computer, but as far as I can tell from reading through Q/A on Amazon this is not the case and they are mixed down to a stereo channel: "This mixer is not a multi-track recording mixer/soundcard, but you can record up to 2 independent channels (left and right) at once, and using recording software such as..."

So in either case it leaves a lot to the imagination, or is outright misleading.

How can I deterministically determine how many actual inputs are exposed to the computer?

Answer 1

I think that example has just thrown you somewhat because of their (frankly awful) description and pathetic list of specs. I can't believe you need to register with them to even download the manual! Usually, it is not difficult to work out and usually manufacturers are more transparent and list FULL specs. Look at this page for a MOTU product: http://www.motu.com/products/motuaudio/896mk3/i-o.html - 8 analog inputs at 192khz, 8 analog outputs at 192khz + 16 channels on ADAT in and out, so (plus mains outs, headphone etc) 28 ins and 32 outs. Simple.

Perhaps the moral of the story is to never trust gear unless it has full specs, and even then to read around for some professional reviews or user experience.

As for small mixers with USB, I've not come across any which send every channel discretely to your computer. The Mackie firewire mixers did do that, but I've not seen any USB equivalent. Not really sure why that is though.

Answer 2

Try googling "4-channel audio interface" or however many channels you are looking for. Often mixers that also offer a built-in USB interface will only give you two channels of input; buying a dedicated interface is your best bet. If you have a rough idea of what you need and how much you're willing to spend, you can also call a music shop and they will be able to point you in the right direction. Often reading manufacturer descriptions can be confusing if you don't have experience, especially if you are looking at lower-budget equipment.

Good luck!