On Tue, 2014-08-26 at 14:08 +0000, Fons Adriaensen wrote: > 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. Thank you Fons, I reported the issue. https://github.com/williamweston/phasex/issues/10#issue-41179099 I've got no doubts anymore, that I experienced the DC offsets too. Regards, Ralf _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
