Capturing Multi-Track Raw Audio?

afex asks: "I've been in and out of bands, and my current one is ready to sit down and put out a nice sounding Promo CD. In the past, I've used a horrible mess of equipment to get this job done. I won't go into detail on what all the microphones were for, but I had 4 going into an analog mixer, mixed down to 2 channels - as well as four other microphones that were unmixed. This left me with 6 separate tracks, which I am now outgrowing. I'd now like to start capturing 8 (or more) channels of raw (delivered via XLR cables from mics) audio. As for quality: 44.1K/16bit is fine. The editing can be done later via software, but my main quest is to get a single piece of hardware (either for my PC or a standalone box) that will ONLY capture the audio - no EQ's, no FX, no mixing, nothing, since that is all done later, on the PC. Got any ideas, Slashdot?" "I used to record it all using 2 stereo USB capture devices (Edirol UA-1A & M-Audio MobilePre USB), as well as the PC's soundcard (left and right). I recorded and mixed with Cool Edit Pro, which is now Adobe Audition. This method has been very buggy, and its time for a change. I don't want to add more USB/FireWire capture cards to the mix, and I don't want to pay a heap for a digital 8-track recorder such as Yamaha's AW16G. What can I do?"

Comments

MOTU 828mkII or 896HD

[Matt Perry]

I use the MOTU 828mkII with Adobe Audition and love it. You can easily record eight channels with it. The one I have uses firewire to connect to the computer but I see on their site that you can also get it with a USB 2 interface.

The only down side is that it only has two XLR inputs. If you need more then you should look at the 896HD which has eight XLR ins and outs. You can chain more 896's together to get more channels. I don't own one of these so I don't know how it compares to the 828.

Re:easy solution

[wcsanders]

I would not recommend any solution that involves Behringer equipment. Behringer is infamous for stealing designs, using cheap parts, and making all around terrible products. I've bought several things from them; most did not last for more than a year, and all of them were dismal quality. I would recommend the Mackie 800R. The Onyx preamps are very solid, and it comes with a very nice firewire interface and software. It puts out exactly what you put in (as accurate as a mic preamp at that price point can be, anyway), no EQ, effects, etc.

Re:Buy better equipment

[ajs318]

Another way of syncing two cards, if they are the same make and model: Find the crystal, which will be either a two- or three-leaded metal can {on an expensive card} or a three-leaded ceramic blob {on a cheap and nasty one}. Probe each pin of the crystal with a 10:1 scope probe; you will see that one will have a "squarer" waveform than the other. Note which one {this is the oscillator output}. Unsolder the crystal from the slave card. Get a 74HC04 and a small piece of breadboard {or use a 74LX1GU04, single gate, if you can get it; even just a simple NOT gate consisting of a MOSFET and two resistors should do}. Plumb this in to any convenient positive supply and 0V. Ground all save one of the 74HC04 inputs. Wire the oscillator output {pin with the squarer waveform} on the master sound card to the remaining input of the 04, and take the output to the opposite hole on the slave card {crystal input}. This should work for multiple slaves: one NOT gate will easily feed more inputs than most motherboards have expansion slots.

How it works: a crystal behaves like a precision delay line. If it's connected between the output and input of a NOT gate, then the "output" of the crystal will change states half a period after its "input" changes state, so forcing the output of the NOT gate to change state; this will cause the "output" of the crystal to change state another half period later. As long as the period of the crystal is longer than the propagation delay of the NOT gate and the capacitances on the two pins of the crystal are unequal {and in any real circuit, they will be different enough} this will start and continue to oscillate. What we just did was to feed the oscillator input of the slave card from the oscillator output of the master card. A crystal has too high an internal resistance to supply more than one gate, and the crystal output must be the opposite of its input; so we have to use a proper NOT gate so the signals at the two oscillator inputs will be in phase with each other.

Re:Neat, potentially overkill?

[Kadin2048]

On the Mac, it's easy - they have Core Audio drivers, and are usable by any well-written Mac application (YMMV with ProTools). But in Garageband, Nuendo, Final Cut, Audacity, etc., they just show up as regular input/output devices. Neat thing with Core Audio is that you can actually route one interface to multiple programs simultaneously (send inputs 1-6 to Garageband, inputs 7-8 are the mix through an outboard piece of gear then brought back to Nuendo, use inputs 9-16 for tape ins in Audacity).

Now that's slick. I haven't really done much with computer-based audio in a while--the last time I had access to a DAW, it was using some version of Protools that wasn't OS X compatible--and I've never used CoreAudio for anything more complex than two channels.

You're right, I can't really think of much reason why you'd want to send various channels to different applications, but it's nice to know the feature exists.

Thanks for the info.