Re: [Sursound] Question about directional bands

[Jörn Nettingsmeier]

On 04/01/2012 11:55 AM, Augustine Leudar wrote:

I am getting a many opinions on this as possible and I have now heard
various answers. It specifically relates to boosted band and, in this
scenario, elevation cues in the median plane . Blauert's 1969 experiment
showed that if an if a narrow band noise or sinusoid wave with a centre
frequency of 8 khz is played to both ears equally  the sound is generally
localized above the head. My question is how does the auditory system
distinguish between 8khz as a directional elevation cue or a boosted 8 khz
that might be present in a soundsource directly in front of the listener ?
So far I have been told its to do with binaular differences between the two
ears (the directional bands may not be the same in each ear due to the
different shapes of the pinna and can be compared, visual cues, envelope
shapes) any clarification or alternatives would be great.


off the top of my head, i think blauerts findings were as follows:

* narrow-band artificial test signals fed to both ears in the same way 
produce unambiguous auditory events located at various elevations on the 
median plane, the elevation depending only on the center frequency.

this phenomenon is more or less the same with different individuals.

* the brain can use elevation-dependent linear distortion of 
sufficiently wide-band signals to infer height, but this only works with 
familiar signals where an un-elevated (and hence uncolored) reference is 
known to the subject.

e.g. some synth signal: practically no height cues
a human voice: usable height cues
your spouse or close friend: quite good height cues

so you can exploit this by boosting any given sound in blauert's 
critical bands to give some height impression, but don't expect miracles.


even with proper soundfield reconstruction, the human ability to judge 
height is not too good, unless the listener tilts her/his head. visuals 
or content usually win over actual direction, i.e. a sound is where you 
think you see its source, and birds are up, footsteps are down.



--
Jörn Nettingsmeier
Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487

Meister für Veranstaltungstechnik (Bühne/Studio)
Tonmeister VDT

http://stackingdwarves.net

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Re: [Sursound] Question about directional bands

[Richard Dobson]

Thanks for the ref. Pity, it is AES, which I am not a member of, and $20 
is a lot to pay for a 29-yr-old paper of mostly anecdotal interest :-(


Richard Dobson

On 01/04/2012 13:36, Eero Aro wrote:

Richard Dobson wrote:

Out of interest - what research has been done on this where the
listeners were lying down?


The subject is not my area, but I know of an old paper:
James Lackner: Influence of Posture on the Spatial Localization of Sound

http://www.aes.org/e-lib/browse.cfm?elib=4554

Eero
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Re: [Sursound] Question about directional bands

[Eero Aro]

Richard Dobson wrote:

Out of interest - what research has been done on this where the
listeners were lying down?


The subject is not my area, but I know of an old paper:
James Lackner: Influence of Posture on the Spatial Localization of Sound

http://www.aes.org/e-lib/browse.cfm?elib=4554

Eero
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Re: [Sursound] Question about directional bands

[Richard Dobson]

Out of interest - what research has been done on this where the 
listeners were lying down? Do they hear such sounds  still as "above", 
or behind their heads? And, in the same vein, one the degree of such 
perception with respect to intensity?


Richard Dobson



On 01/04/2012 12:56, Robert Greene wrote:


Actually, I think the ear/brain does not make
this distinction without pattern recogntion,
in other words, the height impression to the
extent that it arises from spectrum of the sound
depends on what the ear/brain expects the actual
sound to be. There is a similar effect about
frontal versus rear sounds. A
natural familiar type of sound source can be
made to sound behind when played in front if it
is spectrally modified in the way it would be
if it were in fact coming from hehind!
Height perception similarly plays off the
known sound spectrum versus the perceived one
to determine height. But for height it is pretty
crude--7-8 kHz tends to sound up even if it is not.
Cymbals float up in perception even though the sound is familiar
in spite of the source being not up.
This is true in reality as well as in recordings.
Robert


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Re: [Sursound] Question about directional bands

[Robert Greene]

Actually, I think the ear/brain does not make
this distinction without pattern recogntion,
in other words, the height impression to the
extent that it arises from spectrum of the sound
depends on what the ear/brain expects the actual
sound to be. There is a similar effect about
frontal versus rear sounds. A
natural familiar type of sound source can be
made to sound behind when played in front if it
is spectrally modified in the way it would be
if it were in fact coming from hehind!
Height perception similarly plays off the
known sound spectrum versus the perceived one
to determine height. But for height it is pretty
crude--7-8 kHz tends to sound up even if it is not.
Cymbals float up in perception even though the sound is familiar
in spite of the source being not up.
This is true in reality as well as in recordings.
Robert

On Sun, 1 Apr 2012, Augustine Leudar wrote:


I am getting a many opinions on this as possible and I have now heard
various answers. It specifically relates to boosted band and, in this
scenario, elevation cues in the median plane . Blauert's 1969 experiment
showed that if an if a narrow band noise or sinusoid wave with a centre
frequency of 8 khz is played to both ears equally  the sound is generally
localized above the head. My question is how does the auditory system
distinguish between 8khz as a directional elevation cue or a boosted 8 khz
that might be present in a soundsource directly in front of the listener ?
So far I have been told its to do with binaular differences between the two
ears (the directional bands may not be the same in each ear due to the
different shapes of the pinna and can be compared, visual cues, envelope
shapes) any clarification or alternatives would be great.
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[Sursound] Question about directional bands

[Augustine Leudar]

I am getting a many opinions on this as possible and I have now heard
various answers. It specifically relates to boosted band and, in this
scenario, elevation cues in the median plane . Blauert's 1969 experiment
showed that if an if a narrow band noise or sinusoid wave with a centre
frequency of 8 khz is played to both ears equally  the sound is generally
localized above the head. My question is how does the auditory system
distinguish between 8khz as a directional elevation cue or a boosted 8 khz
that might be present in a soundsource directly in front of the listener ?
So far I have been told its to do with binaular differences between the two
ears (the directional bands may not be the same in each ear due to the
different shapes of the pinna and can be compared, visual cues, envelope
shapes) any clarification or alternatives would be great.
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