naturerecordists
[Top] [All Lists]

Re: Understanding Stereo Array Performance (was Re: Olympus LS-10 r

Subject: Re: Understanding Stereo Array Performance (was Re: Olympus LS-10 r
From: "Rob Danielson" danielson_audio
Date: Sat Jul 5, 2008 8:14 am ((PDT))
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.
>


--






<Prev in Thread] Current Thread [Next in Thread>
  • Re: Understanding Stereo Array Performance (was Re: Olympus LS-10 r, Rob Danielson <=
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU