DC offset problem

[skitzzz]

I recorded a guitar track directly to my computer using soundforge 6. Just straight thru my FX pedal to the soundcard. Yea, I know it's pretty cheap, but it's what I got. Mostly just to document new ideas and riffs, and to learn more about recording and digital signal processing. I have my pedal's volume set to %50 on the knob (which is quite loud) and my line in recording volume set to very low to where I get max level with no clipping. I use the DC offset option and it goes to about L:85 and R:-120. This is the best sound that I can get so far, but there's a little problem. For the 'silence' I get a good general Inf. wave, but for the loud part I noticed that it looks like there's a major DC offset occuring. I don't know exactly how to word it, but the positive peaks appear to average 2.5dB and the negative, 6dB according to the scale to the left - making it 'shifted up' like DC offset. It sounds alright to me, but I *know* it could stand to improve. Could someone please explain to me what's going on here and what I can do to fix it, other than buying a mixer or some other kind of expensive box? Should I even worry about it? I do plan on putting eq and compressor and noise gate, etc. to clean it up for when I send it to my friends. There's a pic attatched so u can see.

 

[dachay2tnr]

I use the DC offset option and it goes to about L:85 and R:-120.

I don't use Sound Forge, but what does this statement mean?

Usually any DC Offset processing would be done post recording, in order to correct an offset problem. Are you sure you aren't maybe creating the problem with the above?

Regardless, you can correct the problem by processing the wave using DC offset correction software. If there is none provided with Sound Forge, here's a freebie from analog-x:
http://www.analogx.com/contents/download/audio/dcoffset.htm

 

[SureShotStudio]

hi Skitzz,

if a wave is asymmetrical, it doesn't have to mean that it has a DC offset....
A trumpet or a trombone when recorded will usually look asymmetrical but there is no DC offset. Even some distortion pedals produce a asymmetrical distortion to give it a different sound.

So if your guitar sounds right when recorded and you used the DC offset option after recording everything should be fine. (the DC offset probalbly wasn't nessecary anyway)

greets,

Thomas

 

[skitzzz]

just to clarify, the DC is fine as far as I can see. In soundforge, if ur not familiar with the interface, there's a checkbox that says 'DC adjust', and a 'Calibrate' button in the recording control window. This checks for a DC offset in the signal before the sound is recorded and makes the adjustment on the fly; which is supposedly better than doing it afterwards - reduding destructive post-processing. It's just that I noticed the asymetrical wave that resembles a *major* DC offset, not saying that's necessarily what it is that's happening. just to clarify. Thanx SureShot, good to know.