At 1:36 PM +0000 11/22/09, Raimund wrote:
>
>
>Hi Rob,
>
>Today I made another sample recording with the M10 fitted into a
>piece of foam:
>
><http://www.avisoft.com/scratch/SONY_PCM_M10_baffle.mp3>http://www.avisoft=
.com/scratch/SONY_PCM_M10_baffle.mp3
Interesting experiment, Raimund.
I placed the results from your first recording at the head for
comparison. The soundtrack is well- saturated, adjust playback volume
to suit your personal taste:
http://tinyurl.com/yhh2jaa (3mb QuickTime movie)
I think the stereo imaging of the M10's built-in array might be
better without the baffle. The additional sound pollution in the 2nd
recording makes the evaluation harder, but the overlapping treble in
the middle of the stereo field from the capsules' 90 degree off-axis
peaks seems to improve center localization and presence. The bulging
bass in the center of the field from the near coincident omni mics
does make the space sound flat but to separate these low frequencies
would probably take a much larger, dense baffle. Foam doesn't provide
much separation under 500Hz but it does significantly reduce the
amount of high frequency cross-over.
When omni mics are faced away from each other as they are in Sony's
M10 array, the high frequency response would typically taper-off to
the sides (front) and create a drop in the high frequencies in the
middle of the stereo field. However, according to Sony's response
charts for the M10 mics, there's a peak at ~3.5K Hz at 90 degrees
off-axis that seems to off-set this darker hole in the middle. Adding
a baffle sort of re-introduces the inherent HF "hole" challenge of
the opposing array design.
The EQ changes I opted for appear to support non-baffle use as well.
In the first recording, the treble in the middle of the field seemed
sufficient, but in the baffled recording, the birds didn't have
enough presence without some HF boost in the middle. Note that I
actually applied treble cut to only the sides in the first recording
which reduced treble "hot spots" at the speakers allowing more
horizontal spread across the center. I couldn't get that effect with
the 2nd recording.
I personally like that the mics produce a strong bottom end to work
with. The LF response is a little uneven, but, with careful EQ, it
should be easier for recordists to portray depth.
Before and after takes with a baffle might provide more insights but
the way the factors are lining-up, adding a baffle should not provide
much, if any improvement. If the omni mics were removable, one could
spread them apart and use any number of proven small, stereo arrays,
but the over-emphasized middle from the bottom end imaging is going
to be difficult to modify locked into the recorder's body.
As before, the QuickTime movie does not show the 2nd M-S plugs used
after the EQ plugs. The post EQ M-S plugs are MS -> L/R at unity.
Rob D.
><http://www.avisoft.com/scratch/SONY_PCM_M10_baffle.jpg>http://www.avisoft=
.com/scratch/SONY_PCM_M10_baffle.jpg
>
>The foam that I used is perhaps still a bit too soft, but I think
>that it improved the stereo effect at higher frequencies.
>
>This is the view from the hill with the flock of jackdaws and crows
>where I made that recording:
>
><http://www.avisoft.com/scratch/Arkenberge.jpg>http://www.avisoft.com/scra=
tch/Arkenberge.jpg
>
>Regards,
>Raimund
>
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