I/O Issue - One Side Louder Than The Other

Hello All,

Running an M Audio M-Track Eight Interface. On my master channel I have tried multiple pieces of stereo outboard gear using the I/O plug in.

The issue: The LEFT side is much louder than the right side. So when I send the signal out through channels 7-8 (for example) and return them through inputs 7-8, the left channel (channel 7) is blaring and right channel (channel 8) is about 1/4 of the volume. I can accommodate for the imbalance using the channel gain controls (on the M Audio interface), where I will turn down 7 and turn up 8, but if any of you are experts in I/O please help shed some light on what is going on.

Before anyone suggests it's the cable, the outboard gear, or the interface pre amps - know this: I've tested all that. The outboard gear ins and outs work. The interface channels all work (and their gain knobs work). I've tested all the cables. I've also returned the signal through channels 5-6. Same issue. The interface works fine.

The outboard gear are stereo compressors. These have a "stereo link" feature as well as "bypass" controls. If I bypass the outboard gear - the left channel gets very loud. Even though the signal in logic is a stereo signal with identical volume on each sides. When I activate the compressors, the volume equals out - however this is because the compressor is compressing the left channel more heavily than the right channel - which I don't want. Obviously that's not a solution.

Am I setting this up incorrectly? Is there some switch or setting I need to activate?

You guys are the experts.

Whenever you run into problems like this, simplify, simplify, simplify until the problem goes away.

- Replace the signal with a Test Oscillator plugin, so you know there is equal levels left and right and how much precisely.

- In the next plugin slot, put an IO plugin and bypass it.

- In the next plugin slot put a Meter plugin (Mp). It should read -12 on both channels when using the Test Oscillator in its default setting.

- Patch a cable between Out 3 and In 3, and another one from Out 4 to In 4.

- In the IO plugin, send Out 3-4 and return In 3-4.

- Is the Mp still showing -12 on both channels ? If not despite In3-4's Gains being equal, there may be an input gain switch either on the interface itself or in the control software.

- Once you got equal levels of -12, patch Out 3-4 to your external gear.

- Do it's input meters show equal levels ? If not, check its settings until they do.

- Patch from your external gear into In 3-4.

- Does Mp show equal levels ? If not, your settings on the external gear are wrong. Change them until it does.

- Bypass the Test Oscillator.