[Arny Krueger[_4_]]

"Neil Gould" wrote in message
...

I completely agree with your observations, which is why I'm curious about
trying to remove DC offset in post-processing if there is no point of
reference such as a steady state level without AM signal. Since an xformer
balanced input won't pass DC, I wondered how likely it would be that DC
offset would be passed through the A/D. So, in either case, HPF is not
much
of a solution.

If you are editing audio, and any of the file(s) involved have a DC offset,
there is a very good chance of introducing a click when you cut and paste.
Not just theory, but a fact that many of us who actually edit audio (and not
just pontificate about it) have unfortunately experienced.

You can minimize clicks and pops due to editing by only cutting on zero
crossings, but that is not a 100% solution. You can also minimize clicks and
pops by merging the file segments with what amounts to be a cross fade or
other smoothing technique, but again these are not 100% solutions. Cross
fades and other smoothing techniques essentially turn the clicks and pops
into thumps. The good news is that a thump that is composed of only very low
frequencies can become very hard to hear.

Having a file whose DC component approaches zero over shorter periods of
time is therefore a good thing, because it helps minimize the possibility of
introducing thumps, clicks and pops when you are editing it.

If you apply a HPF to a file, you are ensuring that the average or DC
component of the file approaches zero over a period of time that decreases
as you increase the cut-off frequency. If you zero out the files average
value, then the DC component of the file is only zero for the exact segment
of the file that you processed.