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Re: Acoustic Flow Field Generation


I have also noted degraded recordings from loudspeakers in enclosed
environments.  When I record speech from a loudspeaker and then play this
recording back to a listener on headphones I find it to be less
intelligible than a person simply listening to the loudspeaker in the same
environment. Even though I took considerable pains to calibrate and
balance the recording and playback equipment.

Unfortunately I don't have a direct answer, but in my case I suspect it is
related to imperfect recordings interacting with the acoustic environment.
For example the interaction of reverberation, noise, and the
directionality of the ears vs. microphones (in your case it may be related
to the directionality of the loudspeakers vs. human-speakers).  I suspect
that better recording equipment and perfecting the
calibration/balancing/directionality of equipment might help and of course
reducing the noise.  I would appreciate hearing about any answers you find
through your research.

To close on a more interesting note, the listeners ability to localize a
source certainly must be important to the realness of the walking
sensation.  I'm speculating that Doppler shift at walking speeds would
probably NOT be detectable for speech sounds especially considering the
reverberation in a hall, but it is a thought to ponder.  What about
turbulent air flow noise over the pinna?

Brad Libbey
Georgia Institute of Technology

On Wed, 29 Aug 2001, Michael S. Gordon wrote:

> Dear List -
>     I am interested in capturing the acoustic flow field of a person walking
> down a hallway. Thus far I have made a couple of binaural recordings of (1)
> a perceiver walking past individuals reading text (live) and (2) a perceiver
> walking past a series of loudspeakers projecting an assortment of recorded
> sounds (e.g., human speech, typewriter clicks, etc.). Those who have
> listened to these recordings have found the first set a much more compelling
> indication of the listenerąs motion than the second. There are several
> reasons why this may have been the case: the live readers were fewer, more
> sparsely located, and generally louder than the recordings via loudspeakers.
>      I am writing to the list because I was hoping that some of you might
> have some intuitions or know some references that would help guide me to
> more successfully capture the acoustic flow field of a person walking
> through a hallway. Specifically I am wondering whether live sounds should be
> easier to localize through a loudspeaker than recorded sounds? Furthermore
> should the localizability of the sound sources contribute to the Śrealnessą
> of the walking event for a listener?  I would greatly appreciate any
> thoughts on this issue.
> >             Respectfully,
> >                 Mike Gordon
> -- 
> Michael S. Gordon
> Ecological Acoustics Laboratory
> Department of Psychology
> University of California, Riverside
> Riverside, CA 92521
> 909-787-4579
> mike.gordon@psych.ucr.edu
> http://www.psych.ucr.edu/faculty/rosenblum/Mike_Gordon/MikeGordon_home.html