Computer->M-Audio-FastTrackPro USB->trs outputs 1/2->linein 11-12 of mackie 1202-vlz3. How can i get stereo sound out of the mackie?

Without more information of your speakers and amps we can't really help you. The Mackie board puts out line-level signals and that should drive any connected amp or powered speaker to the full capability. Make sure you are using BALANCED interconnect lines either XLR or TRS cables. Use of TS unbalanced cables costs you 6 DB and also noise pickup. Make sure ALL your gear, amps, speakers etc are powered from a SINGLE receptacle or power conditioning module. Normally you will use the AUX outputs of the mixer by way of TRS cables or balanced lines in a snake to power amplifiers onstage which then connect to the stage monitors. If you have powered monitors the returns of the aux to the stage go to the powered monitors. A heavy duty extension cord brings power back from thee stage power to the mixer.

The problem is that card has only UNBALANCED inputs. You really need balanced or first run the mixer outputs through a DI backwards. Frankly, I would recommend NOT using a card within the PC as there is so much digital noise. Use either a USB or Firewire external convertor and for goodness sakes use balanced lines from teh Mackie... ALL interconnected equipment needs to be powered from the same receptacle or source. M Audio, Roland/Cakewalk and Presonus all make cards as do others.

You connect the powered 15's using balanced cables. The passive speakers you will have to get an amplifier for as the mixer does NOT have a powered output, only line-level audio outputs.
The powered speakers MAY have audio line level outputs to continue to other powered speakers or, as in your case, external amplifiers to drive your passive speakers.
Remember to power ALL interconnected equipment from the same receptacle or source to avoid ground bounce faults that can destroy sensitive circuits in your equipment.

On page 28 of your user manual there is a block diagram. You will find the outputs on the right side of the drawing... They will innclude the mains, the mono, the subs and aux andd the tape outputs. There are a bunch and many are stereo types.

The best way is to use a two-way crossover between the mixer and the amplifiers. In your case, the low output from teh crossover would go to the powered subs, the highs to the QSC. Use the crossover adjustment to set the frequency crossover point to get the sound quality you require.

Dan

Mackie 1604 ---> Crossover --- Highs ---> QSC --->Speakers
'
-----> Crossover --- Lows ---> Powered Subs.

Using two balanced lines either TRS or XLR depending on what is on your M audiointerface, connect the L and R main outputs of the mixer to the L and R inputs of the M Audio. You will need recording software on your computer.

use the xlr (3 prong) main left and right outputs of the board. get xlr to 1/4 inch cables. one end will be 3 prong, to plug into the mixer, then the other end will be a mono 1/4 inch plug, like a big headphone plug. Then you have to get a dual mono 1/4 inch to stereo 1/8 inch adapter and plug it noto the line in. if there is no lone in, but a microphone jack instead, you will get a mono signal instead of a stereo signal. in this case, just use 1 channel of the mixer, instead of both of the stereo outs, and use a single mono 1/4 inch to mono 1/8 inch adapter.

the xlr to 1/4 inch cables can be purchased at a music store. the 1/4 inch to 1/8 inch adapters will probably need to be purchased at radio shack.

RCA jacks do NOT connect to the USB. One is aanalog audio, the other digital.

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Refer to your EV user manual, page 23, part 2.

You run the outputs of the Mackie into the stereo "returns" on the EV.

Use TRS interconnect cables as these are balanced lines.