[LAU] [Bulk] Re: [Bulk] Sequencer suggestions?

[Fons Adriaensen]

On Tue, Aug 26, 2014 at 03:46:59PM +0200, Ralf Mardorf wrote:

> > "2.23  DC Offset Remover (dcRemove, 1207)
> > 
> > Simply removes the DC (0 Hz) component from an audio signal, uses a high
> > pass filter, so has some side effects, but they should be minimal." -
> > http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#tth_sEc2.23
> > 
> > Would this protect against phasex loudspeaker-heater feature? 
> 
> It's said it's not audible, IIRC I sometimes heard a loud, very loud
> single crackle. Could this be caused by a dc offset? 

Yes. The problem here is that the DC offset originates in the
oscillators and is multiplied by the envelope. Hence the result
is not really constant. A highpass filter will remove the constant
or slowly changing part during a note, but not the 'thumps' at the
beginning and end. Depending on the cutoff frequency and the rise
and fall times of the envelope these could still be much larger than
the signal. They won't probably fry you speaker but could result in
clipping and hence crackles. 

The only real solution is to remove the DC offset at the output
of the oscillators, before it enters the rest of the audio chain.

-- 
FA

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