[Threeleggedyoyo]

Running a cheap dynamic mic through xlr into an M-Audio Fast Track, then to Mixcraft.

Generally speaking, I get a nice clean recording this way. However, in certain environments, it picks up an electrical buzz caused by some sort of ground loop or other interference. Unfortunately my dedicated music room is one of those environments.

It largely dissipates if I unplug my laptop and run on battery power, but not entirely.

Any thoughts as to what I should do? If a hardware replacement is in order, please make economical suggestions. However, what I would really prefer would be something that doesn't cost more money.

I thought maybe a good gate vst could take it out. If I run it during recording will it eliminate the buzz? Running it after recording only takes care of it during the parts where I'm NOT singing. It's not worth it to me unless I can get rid of it altogether.

Another thought - is there some way to add additional shielding to my M-Audio device?

Suggestions? Thanks!

[santacore]

Try another mic cable to see if the shielding on your current one is damaged. A compromised mic cable will certainly pick up RF noise and even local radio stations.

You might also want to check your mic to see if the grill is grounded to the body. I have had some mic's buzzing because the connection between the two was damaged.

If you are recording with software, try putting a notch EQ in-line before your record channel. Sweep across the bands to try to pin point the offending frequency.

In my opinion a gate would not be effective for this problem.

Good luck!

[bunnyma357]

You can try plugging AC plugs in using a "cheater" plug to lift the ground to see if that eliminates the problem - although this may not be wise from a safety perspective.

http://en.wikipedia.org/wiki/Cheater_plug

You might also try an XLR isolation transformer to see if that removes the noise, more expensive, but safer.

http://www.bhphotovideo.com/c/buy/Hum-Eliminators/ci/15139/N/4294240041

Jim C

[Speedskater]

It can't be a ground loop because the mic input has only one path.

Bill Whitlock has a mic circuit tester in some of his papers:
http://www.jensen-transformers.com/apps_wp.html
See page 24:
http://www.jensen-transformers.com/an/generic%20seminar.pdf

Jim Brown is also a HAM so some of his papers cover interference and mic circuits:
http://www.jensen-transformers.com/an/generic%20seminar.pdf

[Ethan Winer]

It largely dissipates if I unplug my laptop and run on battery power, but not entirely.

If the buzz changes when you unplug the laptop, this can be a ground loop. The other likely culprit is solid state light dimmers. You don't describe all the pieces you have well enough. How many audio things are plugged into the wall AC outlet and also connected by audio wires?

--Ethan