klangstrand wrote:
>
> Hi Peter
> Sorry for my inprecision
> What I meant was that, when using the controls in the
> Spectral View, I raise and lower the spectrum=B4s sensitivity,
> to help orientate.
> I usually put a cutoff on -120db, so everything below that
> will not show, other times a lower sensitivity will be
> apropriate. I find the controls very helpful to adapt to
> different needs.
That makes sense, and it's what I do too in Audacity. Unfortunately Audacit=
y doesn't let you see the results of changing settings, so you have to cont=
inually go into the preferences (control+P shortcut) to make further adjust=
ments. I've requested that this be changed by the developers. I've also req=
uested that they allow for saved sets of spectrogram parameters, so if anyo=
ne wants to track down those change requests and vote for them, please do.
I forgot to mention that, depending on what the recording is for, it can be=
worth paying special attention to the low frequencies, say below 500Hz, be=
cause a lot of human noises that might be undesirable, e.g. thumps and bang=
s, are clearly visible as spikes, whereas they could be too faint to notice=
unless you're listening carefully with headphones.
I increase the FFT window size to a high value, say 16384, and limit the fr=
equencies to 0 to 500Hz and quickly scan through to mark the position of an=
y spikes. Often they turn out to be wing flutters or twigs falling. Unfortu=
nately the higher the FFT window the slower the spectrogram page generation=
, so it's worth experimenting with lower values first.
Peter Shute
> --- In
> <naturerecordists%40yahoogroups.com> , Peter Shute
> <> wrote:
> >
> > Anders, what exactly does "trim the view of noisefloor" do?
> Does it actually remove noise before calculating the
> spectrogram, or does it just use tricks like adjusting image
> brightness and contrast or despeckling?
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