Opps--
I started the _sketchy notes_ below to myself
yesterday morning in response to Greg's
observations about the LS-10's array. They are
jumbled, undeveloped and not ready for reading.
The prepared response is
http://tech.groups.yahoo.com/group/naturerecordists/message/33733
I must have cued the draf by mistake at some
point. Sorry to post such a mess! Rob D.
=3D =3D
At 1:46 AM -0500 7/5/08, Rob Danielson wrote:
>At 1:15 PM +0000 7/4/08, Greg Simmons wrote:
>>--- In
>><naturerecordists%40yahoogroups.com><naturerecordists%40yah=
oogroups.com>
>>"oryoki2000" <>
>>wrote:
>>
>>> In my brief experiences with small recorders, the LS-10 stands out
>>in
>>> the way its built-in mics produce a "wider" soundscape. Most small
>>> recorders have mics that point forward, parallel to each other. The
>>> LS-10's mic capsules, in contrast, point away from each other in a
>>90
>>> degree spread.
>>
>>The LS10 uses a technique similar to one mentioned by the late great
>>Michael Gerzon in an article about stereo shuffling and spatial
>>equalisation published in the July 1986 issue of Studio Sound
>>magazine. This involved two cardioids crossed around 115=B0 to 120=B0,
>>facing outwards, and spaced 5cm apart. The LS10's quoted width of
>>48mm puts the capsules the right distance apart, although they seem
>>to be at a narrower angle than Gerzon suggested (which may strengthen
>>the centre image a little due to it being less off-axis).
>>
>>According to Gerzon:
>>
>>"Remarkably, for normal stereo listening configurations, it turns out
>>that the 5cm spacing produces roughly the same phase/amplitude
>>relationships between the two ears of a listener in the stereo seat
>>as does a live sound from the same apparent direction up to about
>>2kHz =96 and in this respect is better than true coincidence. Such 5cm-
>>spaced crossed-over cardioids, angled about 115=B0 to 120=B0 apart, seem
>>to be an optimal cardioid technique for stereo imaging accuracy."
>
><http://www.audiosignal.co.uk/Resources/Stereo_shuffling_A4.pdf>http://www=
.audiosignal.co.uk/Resources/Stereo_shuffling_A4.pdf
>
>>
>>Perhaps this explains the LS10's impressive stereo imaging
>>capabilities?
>
>The capsule types and mathematics could be close.
>Vicki's 183's seemed to l spread. That's just one
>attribute among many (but it was the most obvious
>and it isn't that obvious).
>
>Rich Peet and I spent a day testing three arrays
>in a quiet, snow-blanketed hollow and I made this
>video:
>
>Each of use preferred a particular array and
>often our reasons would contradict. People who
>want to al
>
>that Vicki tested had better spatialization. See what you think?
>
>better localization than the built-in mics. Most
>stereo arrays should be able to portray what Greg
>Peterson and I were able to assess in his
>LS-10/built-in recording. There are many
>qualities on can listen for stereo imaging beyond
>this and difference in monitoring will play a
>huge role in people's final preferences. Stereo
>imaging is probably a lot trickier to evaluate
>"universally" than qualities like mic self-noise
>and mic pre input noise. We can also ask maby
>different things from stereo from represebtaion
>of acoustic space to dramatic effects. And think
>of how differently we often interpret tests.
>
>>
>>Interestingly, Gerzon's article also mentions the technique of
>>spacing the mics a small distance apart and angling them inwards (as
>>used in the Zoom H4), but suggests that although it livens up the
>>sound, it degrades the stereo imaging - something my own experiences
>>with the H4 agree with.
>>
>>- Greg Simmons
>
>I would very much like to enjoy a much better
>perceptual understanding of the precise qualities
>afforded by the many stereo arrays there are to
>work with. Rich Peet and I set-out a large test
>area last February in a quiet location and tested
>three arrays for localization and depth with
>sounds from 100' out to 700'. The arrays seem to
>have much greater differences in imaging than I
>expected and it was tempting to draw
>conclusions/preferences. It taught me that from
>the It wil take a quiet location in order to
>discern the subtleties and provide enough
>matching bacjground to be able to exhaustively
>
>really of Now that I live in a quiet location, I
>want to set-up an array of speakers so that I can
>start testing stereo and surround array imaging.
>There are quite a few folks who avidly pursue the
>principles Gerson laid-out. I've not been able to
>test how this approach compares to arrays that
>use head-spacing. Most of them rely on
>processing applied to already recorded files
>including complex ones as with ambisonics and
>simpler ones like M-S. I'd like to hear that they
>work marvelously, but every time I've had a pair
>of good headphones on and field tested many
>placement options, separations that were ear
>spaced or larger produced better localization,
>depth and realism. In my opinion, Vicki's recent
>DIY 183 rig is another example among many.
>
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