[linux-audio-user] One channel clipping on centred mono source

qb at f2s.com qb at f2s.com
Wed Jan 25 18:07:29 EST 2006

Hi everyone

I've been lurking around for a while but this is my first post -- I had hoped
that that would be to post some music, but I've encountered a bizarre problem
during mixdown. Well, it seems bizarre to a relative newbie like me! I hope
this is the correct place to be posting as the problem seems to be a general
sound/music one rather than being Linux specific.

I have a piece that I am mixing in Ardour. None of the tracks are going over 0
dB. The master channel is not going over 0 dB.

The kick drum is on a track on its own; it was recorded from Hydrogen using the
Natural Studio kit free samples. It is a mono file in a mono track. I have the
SC1 compressor and the three band parametric with shelves pre-fader. It is
panned absolutely dead centre and when playing back in Ardour everything sounds
fine and the kick sounds central through my nice new Wharfedale studio monitors

However, when I exported to wav there was terrible clipping. A quick look in
ReZound showed the problem: there was a mass of clips in the left hand track.
Closer visual and aural inspection showed that the clipping is from the kick

In the quieter sections I can see spikes in the right hand channel, too, when
the kick er... kicks, but they are a lot smaller and nowhere near clipping. I
have tried running the kick with a limiter in Ardour and bouncing down again --
that gets rid of the clipping but the transients are still so much bigger in the
left channel that the kick just sounds to be panned left.

I've played around with applying limiters in ReZound but I'd have to really
crank them up (or should that be down?) to get the kick transients to the same
size in both channels and would end up taking the tops off quite a lot else in
the left channel in the process.

I don't understand why a centrally panned, mono file should only clip in one
channel -- I would expect it to clip both sides more-or-less evenly. What's
causing this problem? Is it a problem or have I just misunderstood something?

And most importantly, how do I get my kick drum back dead centre without
applying a limiter to the entire left channel?

Thanks in advance. Oh, and sorry for the long post!


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