Hi Peter
Sorry for my inprecision
What I meant was that, when using the controls in the Spectral View, I rais=
e and lower the spectrum=B4s sensitivity, to help orientate.
I usually put a cutoff on -120db, so everything below that will not show, o=
ther times a lower sensitivity will be apropriate. I find the controls very=
helpful to adapt to different needs.
So, there=B4s no difference in the processing, only visual adapation.
-A
--- In Peter Shute <> wrote:
>
> Anders, what exactly does "trim the view of noisefloor" do? Does it actua=
lly remove noise before calculating the spectrogram, or does it just use tr=
icks like adjusting image brightness and contrast or despeckling?
>
> I use the spectrogram in Audacity to scan through my recordings, although=
they're not usually more than three hours long.
>
> I find it takes some experimenting with spectrogram parameters to make ca=
lls visible, and also the horizontal and vertical scales.
>
> I generally view a minute or two per screen, and Audacity lets you move a=
page at a time with Page Up and Page Down. I add comments to a label track=
when I find something interesting. I also prepopulate another label track =
with the actual times every minute (e.g. 6.00am, 6.01am, etc) so I can easi=
ly tell what time a call was made. (I've written an Audacity plugin for tha=
t, if anyone wants it.)
>
> An advantage of viewing spectrograms is that if you find something intere=
sting, you can quickly scan again looking for fainter instances of that cal=
l you may have missed now that you know what it looks like.
>
> If I had a 24 hour recording to work through I'd consider listening to, s=
ay, 15 minutes of each hour, and only looking at the rest if I find somethi=
ng interesting in those samples. If I had more recordings taking place whil=
e I was processing the backlog, I see no alternative to this unless I had h=
elp.
>
> Another thing I do is to put the recordings on my phone (and more recentl=
y my iPad) so I can listen to them on the way to work on the train. I break=
them into one minute sections, named after the start time of each section,=
so I can more easily tell where I'm up to and make notes about something I=
heard and want to check more carefully at home. Audacity can use the time =
labels I created to split and name the sections as it exports.
>
> I'd like to be able to view spectrograms on the iPad, but I've found no a=
pps that will display them. I've been experimenting with creating them as m=
ovies, which iPads are very good at displaying. The plan is to still break =
them into small segments, perhaps 5 minutes long. I'd love to be able to ma=
ke notes directly in the movies, and I'm hoping something like iMovie will =
allow that.
>
> Peter Shute
>
> > -----Original Message-----
> > From:
> > On Behalf Of klangstrand
> > Sent: Monday, 8 April 2013 6:18 AM
> > To:
> > Subject: [Nature Recordists] Re: Reviewing long recordings
> >
> >
> >
> >
> > Hi!
> > My solution is spectral view. Most often I use Soundtrack
> > Pro, or Audition. Audacity has it also, and is free.
> > The spectral view easily shows when something "different"
> > happens, that would otherwise be invisible in waveform, like
> > high pitched things, that don=B4t carry alot of energy, respectively.
> > You can also trim the view of noisefloor so that you see
> > low-energy things happening aswell, in addition to choose
> > frequency range. Thing sticks out pretty fast.
> > After a while one gets a hunch of types of activity looking
> > at the spectrum. Even pointing out different species. Every
> > bird and animal has its distinct drawings.
> > I get through hours of recordings pretty fast this way, if
> > that=B4s what I need for the task at hand.
> > Best
> > -Anders
> >
> > --- In
> > <naturerecordists%40yahoogroups.com> , "chrishails50"
> > <cjhails@> wrote:
> > >
> > > Dear all
> > >
> > > Related to my last question, I wonder if anyone has any
> > great tricks for reviewing long duration recordings ?
> > >
> > > I have over the years amassed enough reasonable mics and
> > machines to have at least two sets (and maybe a third) that
> > can be left out unattended overnight. I would like to survey
> > my local woods and forests and catch some of the owls that
> > are out there that I have not yet recorded.
> > >
> > > But my question is how to review an 8-10 hour session
> > efficiently ? In the past I have had them playing background
> > whilst I do other tasks, but normally I can only spend maybe
> > 2 hours doing that. I then moved on to scanning the waveform
> > files (for night-time this works I think): I apply a 100%
> > notch filter below 600Hz to get rid of passing planes and boy
> > racers then scroll the waveform (I use Audition 3)and look
> > for peaks that could be interesting sounds. But as I have
> > just discovered even this takes a chunk of time if I have two
> > machines running overnight.
> > >
> > > I know a real field guy would spend the night wandering the
> > forest with his parabola, but I have a day job too.....has
> > anyone else faced this ?
> > >
> > > Thanks for any tips or ideas.
> > >
> > > Chris
> > > http://www.wildechoes.org
> > >
> >
> >
> >
> >
> >
>
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