wave file 'off centre'!?

[Fishybob]

I mix in SX2 and edit complete mix in Soundforge 7.

I spent ages last night mixing my new tune (Early Pearl Jam ish). I found that when I imported it into Soundforge to trim the start finish (Old habit that I haven't shaken off yet) the wave form seemed 'off centre'. It's in stereo but in each of the channels (L+R) the wave dips below 0 in the middle of the channels. This only happens in the first verse where the big guitars don't feature.

Could this be a phase issue?? I've used this setup for a while but never even thought that this could happen.

Can someone enlighten me?


*** I hope that makes sense. I didn't think to take a screen shot last night.

[lbanks]

Try using the DC Offset tool in Sound Forge.

[Fishybob]

Noob question... what is DC offset?

I'll do it as soon as I get home but I'd like to know what is actually is.

[lbanks]

This is how it described by the Expert Center-
"DC Offset
DC offset is an imbalance that sometimes occurs in A/D converters (see WFTD archive "A/D Converter"). When working with audio is it desirable to have only the audio program material passed through the signal path. Almost by definition audio, being a periodic waveform, is an AC (Alternating Current) signal. DC (direct current) is of the non alternating or periodic variety and thus has no constructive purpose as part of an audio signal. It is merely a constant voltage that is present which can eat up headroom (see WFTD archive "Headroom") and cause clicks and pops during editing."

This is how Soun Forge explains it-
"DC offset occurs when hardware, such as a sound card, adds DC current to a recorded audio signal. This current results in a recorded waveform that is not centered around the baseline (-infinity). Glitches and other unexpected results can occur when sound effects are applied to files that contain DC offsets. Sound Forge can compensate for this DC offset by adding a constant value to the samples in the sound file."

[Farview]

This could also be caused by a compressor with the attack and release set too fast. It could also be the natural waveform of the instrument that you are listening to. If you find the instrument that is doing it, add a low cut at 30hz. If that helps, it was DC offset. It would be better to fix the tracks that are affected instead of the entire mix.

[Fishybob]

FOUND THE PROBLEM!

I re-opened the mix file last night as saw the obvious problem. I had another guitar track that wasn't working in the mix that should have been muted and wasn't. When I opened this wavefile - Off centre!

Simply deleted section and remixed - Perfect!


Thanks guys. I'll go sit in the corner now.