It’s the old monitor on your mixer problem. inSync reader Randall L asks:
“I have not been able to solve the problem or my PC’s monitor inducing hum and noise into my mixer. Having to turn off the screen each time I hit the REC button in my ADAT-PC studio is not my idea of optimal performance. It is a problem for many home studios I’ve seen.”
We went to service guru Mark (McGyver) Phillips for this one.
“I believe an EMI field from the monitor is causing the problem, most likely from a switching power supply. There are far too many unidentified variables here for a definitive answer.
- Be SURE the computer and mixer are attached to the same solid ground. They should also be on the same 120 AC phase.
- Magnetic fields follow the inverse-square law. Much like an “Ex spouse” … nothing works better than distance! While listening to the noise, lift the monitor away from the mixer. You may find that 6 to 12 inches of separation ‘solves’ the problem. Raising the monitor shelf may be all that’s necessary.
- If you don’t have the space, or desire, to raise the monitor; the only other option is shielding. I have had success placing a heavy piece of Aluminum (0.5″/15mm thick) under the monitor. You can find one at your local scrap yard. Attach a ground lead from the plate to a center screw on a duplex outlet, which has a known good earth ground.”
EDITOR’S NOTE: I have also found vast differences in the shielding that is built in to various monitors. Sometimes that is one of those hidden differences between two monitors that differ in price by a hundred or so dollars, yet look the same otherwise.