I'm a little confused... What kind of mixer are you using? and this interface usb device I'll have to look up... basically the usb device is coming from your pc, then you'll need a wire to connect the usb device to the mixer... then the monitors get hooked up to the mixer...
Added (24/May/09, 6:39 Pm)
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Oh ok... I just looked at it.. the Alesis is the mixer... wow nice..
it basically looks like my Mackie Vlz 1202 pro mixer...
Does your PC have a good sound card? Or are you using onboard sound from the motherboard?
If the outputs on your PC are 1/8 inch like most (walkman headphone sized), than you'll need an adapter to get from a single 1/8 to whatever input you want the pc channel to be.... ie, rca, 1/4 inch...
I run an monster cable (one side rca and the other side two 1/4 inserts that go into my Mackie... My PC gets its own channel on the mixer... That way i can attach other devices to the mixer and blend with what i create on the PC...
The onlyh downfall is that i need an external recording device for lcapturing whatever else i add to the Mackie from the PC...
Hope this Helps a little... if not just ask away... lol