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10. Re: artifact in spectrogram created using Raven

Subject: 10. Re: artifact in spectrogram created using Raven
From: "Klas Strandberg" klasstrandberg
Date: Wed Jul 18, 2012 11:18 am ((PDT))
Raimund, John,

Then I will rest my case! Thanks!

Klas


At 19:27 2012-07-18, you wrote:
> > Is there any setting that you can do on a PMD-680 that cuts
> > everything over 6k and creates clearly audible reverb and echo??
>
>Hi Klas,
>
>The recorder was set to the MP3 file format at a bit rate of 32
>kBit/s, which causes that 6 kHz low pass effect and the strange
>"audible reverb". This effect is very similar to a poorly adjusted
>FFT-based noise reduction filter, where random sound bits
>occasionally pop up out of the noise-reduced background noise floor.
>
>As Dan already pointed out, these effects can also be experienced on
>your mobile phone or on SKYPE. Just this morning I have been called
>by someone through SKYPE and I did understand next to nothing due to
>the low bit rate...
>
>Regards,
>Raimund
>
>
> >
> >
> > At 18:11 2012-07-18, you wrote:
> > >--- In  Klas Strandberg <telinga@> wr=
ote:
> > > >
> > > > Sorry, but I have to straighten this thread out for myself:
> > > >
> > > > Gabriel says: Even though people have said these are bad recordings=
,
> > > > and I said you will run into trouble in peer review later for
> > > using MP3.......
> > > >
> > > > Are you saying that Lauras files sound the way they do
> because it's MP3??
> > >
> > >Well, I guess at least three issues emerged in the same thread.
> > >
> > >1) What is the cause of the artifacts in Laura's recording? My
> > >impression was that some knowledgeable people thought it could be
> > >low bit rate MP3 alone. Others have put forward different
> > >explanations. Of course it will be impossible to say for sure on the
> > >basis of the sound file alone. This requires testing the equipment
> > >with different settings, and comparing it to reference equipment.
> > >
> > >2) I said, perhaps a bit harshly, that MP3 should not be used for
> > >scientific recordings (also not if it is not the cause of Laura's
> > >problem). This was perhaps too strict, as Dan correctly pointed out,
> > >but in general MP3 is a bad choice. Science is expensive in terms of
> > >money and time. People will be grateful later if you spend a bit of
> > >money on an extra memory card, and used PCM/flac for recording.
> > >
> > >3) For nonscientific purposes, what bit rates are acceptable for
> > >good quality? It is not surprising that the opinions on this vary :-)
> > >
> > >Best, Gabriel
> > >
> > >
> > >
> > >
> > >------------------------------------
> > >
> > >"While a picture is worth a thousand words, a
> > >sound is worth a thousand pictures." R. Murray Schafer via Bernie Krau=
se.
> > >
> > >Yahoo! Groups Links
> > >
> > >
> > >
> > Telinga Microphones, Botarbo,
> > S-748 96 Tobo, Sweden.
> > Phone & fax int + 295 310 01
> > email: 
> > website: www.telinga.com
> >
> >
> >
>
>
>
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>
>Yahoo! Groups Links
>
>
>
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email: 
website: www.telinga.com









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