Hi Rob,
Yes, I also noticed that Sony's left channel is down a bit. I placed
the stack of recorders directly on the ground and the Sony was the one
on the bottom. So, the left mic might have been shaded by the vegetation.
I must admit that this test was made in a quick and dirty way. So, I
do not claim that it is very representative...
One of the biggest problems might be that the microphone orientation
is different on the various recorders (and the pick-up patterns of the
individual microphones itself might also differ).
So, the different angels between the microphones (180=B0, 120=B0 and 100=B0=
)
should be responsible for the varying stereo images.
One interesting test setup would be for instance to point all the left
(or right) microphones of the various recorders exactly to the sound
source in order to examine the sensitivities of the mic capsules more
accurately.
I believe that there is no significant loss of quality in the posted
.mp3 files because the background noise levels are relatively high,
which should mask any potential compression artifacts (I used the LAME
encoder). Here are the uncompressed .wav file versions:
http://www.avisoft.com/test/R09_field.wav
http://www.avisoft.com/test/DR-1_field.wav
http://www.avisoft.com/test/LS-10_field.wav
http://www.avisoft.com/test/PCM-D50_field.wav
Regards,
Raimund
Rob Danielson wrote:
>
> Hi Raimund--
> Thanks for making it possible for us to gain a
> sense of the built-in mics and arrays!
>
> While comparing the arrays:
>
https://pantherfile.uwm.edu/type/public/media/DR1-LS10-D50-R09_CLIPS_Sor3Lr=
g.mov
> (4mb, 16b/48K, QuickTime movie, adjust playback
> volume to a comfortable level).
>
> I noticed that the Sony's left channel is down
> quite a bit. Do you know the reason for that?
>
> Also, in the clip I extracted, the birds in the
> later half seem to be portrayed as centered by
> some of the mics/arrays and clearly to the right
> by others. Do you happen to recall which imaging
> is more correct?
>
> The supplied mp3's were 128 kbps, so some quality
> loss can be expected from that compression.
>
> Rob D.
>
> =3D =3D =3D
>
> At 8:42 AM +0000 5/27/08, Raimund Specht wrote:
> >Last Sunday I tried to compare four of the new "point-and-shoot"
> >recorders with their internal mics in the field (in Berlin, Germany).
> >I placed them all on a stack one above the other and recorded the
> >following tracks simultaneously:
> >
>
><http://www.avisoft.com/test/R09_field.mp3>http://www.avisoft.com/test/R09=
_field.mp3
>
><http://www.avisoft.com/test/DR-1_field.mp3>http://www.avisoft.com/test/DR=
-1_field.mp3
>
><http://www.avisoft.com/test/LS-10_field.mp3>http://www.avisoft.com/test/L=
S-10_field.mp3
>
><http://www.avisoft.com/test/PCM-D50_field.mp3>http://www.avisoft.com/test=
/PCM-D50_field.mp3
> >
> >I tried to match the different recording levels a bit, but the results
> >it might not be perfect.
> >
> >On the SONY PCM-D50, the mic orientation was set to 120=B0. This is the
> >reason why the left and right channels are audibly reversed.
> >Unfortunately, the sample rate on the PCM-D50 was only 22.05 kHz (I
> >simply forgot about that while struggling with the numerous devices).
> >There was a soft breeze. I therefore covered the stack of recorders
> >with a T-shirt in order to reduce the wind noise a bit. There is of
> >course still some noise originating from the reed on the left channel
> >(right channel on the PCM-D50).
> >
> >I believe that this real-world test reveals some interesting
> >differences (certainly on the frequency responses of the different
> >microphones and the nature of their noise) but it also demonstrates
> >that it is quite difficult to get reliable results under field
> >conditions.
> >
> >Regards,
> >Raimund
> >
> >
>
>
> --
>
>
>
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