Sound Forge 6.0 - Reading the levels

[steveanthony]

I'm curious as to why, when recording a mono mic feed (voice only - speech), the wave form runs hotter on the top portion of the level than on the bottom. For example why is the wave registering from Inf to -6 db on the top half (on the average) but only Inf to -12 on the bottom portion of the wave? I have changed polarity on my mic pre and it will do the opposite. So I'm wondering if there's a signal or impedance issue. I'm running a Gefell M930 into a Focusrite VoiceMaster Pro, though this has occured with other condensor mics. The sound card is an Echo MIaMidi. Or is this normal?

 

[TaylorEGO]

for what it's worth, I get that all the time...
with all different kinds of mics, all kinds of preamps.
But it doesnt seem to effect the sound.

 

[crankz1]

It's called DC offset, and can be caused by any piece of hardware (preamp, soundcard etc...) that adds any DC current to the recorded signal. That added current results in a waveform that is not centered at the 0db crossing (infinity).
Extreme DC offset in audio can actually cause damage to speakers after extended periods. It can also cause drift and other abnormalities when run through additional DSP.
Go to Process > DC offset. You can have Sound Forge scan and correct or you can manually set the amount of offset.
AnalogX offers a real-time DC offset plugin as well.

HTH

 

[steveanthony]

Thanks. One more question - what's considered extreme?

 

[crankz1]

To my liking, I wouldn't be to comfortable running the 6db offset that you are getting.
Best thing to do is just correct it and move on.