Turtlerock Forum

Hi all,

I have an M-audio Delta 44 interface (PCI) and an M-audio fast track pro (USB). Both are somewhere in the prosumer product bracket. For financial reasons, have to re-sell one of them. I'm planning on keeping the PCI interface, mainly for the reason that sometimes I need more than two inputs and two of the inputs on the USB audio interface are spdif, meaning I would have to put together an external analog to spdif converter (have one on a bare pcb out of a broken soundcraft mixer).

So the real question is... should I bother building this spdif converter box so that I have the flexibility of a USB portable audio interface, my main concern is phase issues from the latency of the spdif converter when using multi-mike setups. (4 channels spread over 2 completely different and separate AD paths)

Thoughts, suggestions?

Thanks,
Steve.

OK so I rigged it all up, external power supply and clip leads going everywhere to connect up this old analogue to spdif converter board. Now my USB interface has a total of 4 analogue inputs, two of them using the internal ADC and two of them using the external ADC.

interestingly the latency of the external soundcraft ADC compared to the internal one was only about 20 samples (44100 khz sample rate) so thats approxiamately four ten thousandths of a second or equivalent to placing two mics 13cm apart, so I guess in most circumstances I wont have a problem unless close miking the same sound source with the two different ADC signal paths.

Any thoughts?

I know this is extreme boffinry but I cant help it... Im a tech. (unfortunately not a sound engineer)

Thanks.

Stephen C wrote:OK so I rigged it all up, external power supply and clip leads going everywhere to connect up this old analogue to spdif converter board. Now my USB interface has a total of 4 analogue inputs, two of them using the internal ADC and two of them using the external ADC.

interestingly the latency of the external soundcraft ADC compared to the internal one was only about 20 samples (44100 khz sample rate) so thats approxiamately four ten thousandths of a second or equivalent to placing two mics 13cm apart, so I guess in most circumstances I wont have a problem unless close miking the same sound source with the two different ADC signal paths.

Any thoughts?

I know this is extreme boffinry but I cant help it... Im a tech. (unfortunately not a sound engineer)

Thanks.

Yes you'll still get phase issues with 20 samples difference, I'm sure I'd notice it.

If you REALLY need more than two inputs regularly I'd suggest you consider selling both and upgrading your interface or mixing the multiple tracks to stereo before they get to the box.

If you can't afford to upgrade maybe you don't need the extra inputs and you'd be better off working with what you've got and hiring a studio / gear when a particular project calls for it.

Steve,

What do you think of the Delta 44? I've been entertaining the idea of upgrading from my 2in/2out card to a 4/4.

Thanks Heathen and Text for your suggestions, its really appreciated.

I'll probably try and sell the USB soundcard.

I picked both of these up for real cheap on *bay as a result of spending wayyy too much time keeping an eye out for bargains!

Ausrock, I've read good things about the Delta 44 on the internet, but haven't opened the box yet... in case I decide to re-sell it... trying to keep it as a "new" item. Will let you know after I've played around with it.

BTW, I'm quite impressed with how well the fast track pro works... good features for basic studio on the go use, latency only 128 samples with a P4 with 512MB, Protools 7.4 Demo Version, WinXP Pro. Its a really tidy unit, though a little plasticky but too early to comment on the audio quality.

Peace to you all!