Re: More on scrolling spectrograms

["Avocet" madl74]

> I forgot to mention that I can hear a ringing sound when I play the
> 1/5 speed Skylark. I did a spectrum analysis in Audactiy, and it's
> about 4400Hz, i.e. close to 1/10 of 44.1kHz. Is this some sort of
> artefact from slowing it down?

Peter,

The artefacts most likely don't come from the recording, but from
de-digitising (D to A) of the slowed track now effectively sampled at 
8820s/s without the benefit of any filters tuned around
8820Hz and/or sub-harmonics.

You could reduce the audibility of these by recording or re-recording
at a high sampling rate before slowing it down. For instance recording
at 96ks/s reduced by 5 gives an effective sample rate of 19.2ks/s.

David

David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce