reading wave forms

[dobro]

Sometimes when I cut lower frequencies, the entire waveform pops up the screen some distance, and there's more above the mid-line than below it. Does that mean that lower frequencies are represented below the line, and upper frequencies are represented above it?

[matty_boy]

It means that your processing has changed the dc offset. You should be able to fix it.

[Seanmorse79]

I was always under the impression that the waveform strictly represented amplitude. My only guess is that the lower frequencies you're cutting represent a large amount of that amplitude.

[dachay2tnr]

I think Matty Boy has your answer. Does the entire wave look like it has shifted up (or down)? Do you have a tool to measure DC offset?

If not, there is a free one here:
http://www.analogx.com/contents/down...o/dcoffset.htm