Check the audio inputs on the MediaMatrix. The audio input has 8 inputs and 8 outputs. Make sure that your cords are plugged all the way into the input on the MediaMatrix's housing. The input will be labeled "Input." The input cord should click into place when it is secure.
Go to the software menu on your computer and boot the Peavey MediaMatrix software by double clicking on the software icon. Click on the "Channels 1 to 4" icon in the software menu. Click on the "Line" box if you are using a direct line from your instrument. Click on the "Mic" icon if you are using a microphone. Click on the "None" box for the channels that you are not using to mute them.
Adjust the gain setting on the software window if you are getting distorted sound. Click on the channel that is getting bad sound quality. Click on the "Full Scale Sensitivity" menu and then click on the decibel menu. You should see "+30dBu" in the menu. This is the gain on the channel. Lower the gain by click on the "1 to 8" icons at a lower level of gain.
Click on the "Mute" button if you aren't getting any sound from one of your channels. The "Mute" button is located above the "Level" icon on the main dashboard. Select your channel and then click "Mute" to get your sound working on that channel.
Click on the "Level" button to adjust the volume on your channel. Having a high level can overpower your mix. Click on the digital knob via the dashboard and move the mouse to lower the level on the channel.