"Matrixmusic" wrote in
oups.com:

I have 6 inch ventelation going into my studio and it's causing noise.
Any suggestions on how to reduce the noise floor through muffling the
noise

There are two sources of noise: machine noise and air movement. I fixed
the air movement problems.

The main return to my furnace is close to my recording area. Previously I
had to turn off the furnace while recording and editing.

When I had the unit replaced, I had requested
1) two returns instead of one
2) both farther from the unit (more ducting)
3) flexible ducting (dissipates noise and vibration from the fan)

These three changes had a huge effect on the noise levels. I still won't
record with the furnace on, but I can now monitor and mix with relative
ease.