Raimund,
Thank you for making the tests, your recorder noise page is=
a real bonus to those hunting for their next recorder :) I see a soundfie=
ld mic on the horizon.
Related to mic low noise,
Have you ever used cross correlation to determine very low noise levels? Cr=
oss correlating both left and right channels ? I recently ran into this art=
icle:-
http://www.gracey.com/downloads/nor_low_noise.pdf
Which is about measuring very low sound pressure levels. I measured my anec=
hoic chamber with a pair of 100mV/PA mics interesting results.
-Mike
--- In "Raimund" <> wrot=
e:
>
> Hi Rob,
>
> Yes, the SONY Hi-MD recorders (and the KORG MR-1000 with its high noise f=
loor despite of the eight AA batteries) are exceptions.
>
> Supply voltage converters could be used to address this issue, but they w=
ould unfortunately also reduce the battery life, which seems to be the reas=
on why this option is not being used in the smaller pocket recorders.
>
> Regards,
> Raimund
>
>
> Rob wrote:
>
> > Interesting rule of thumb. An exception would be the Hi-MD units
> > that operate on one AA, 1.5 volt battery. Can a voltage upverter be
> > used? And the phantom circuits can cause fits too. Rob D.
> >
> > =3D =3D =3D =3D =3D
> >
> >
> > At 3:15 PM +0000 4/8/10, Raimund wrote:
> > >Yep,
> > >
> > >These findings support the general rule of thumb that the preamp
> > >noise performance of a recorder is primarily determined by its
> > >supply voltage or the size of its batteries (assuming that the
> > >designers did not made a major mistake). Once the supply voltage is
> > >at least about 6 volts, it is relatively easy for the designers to
> > >select suited low-noise op amps.
>
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