Fw: Fw: sursound: The pinna and Ambisonics/cross post (Peter Lennox )

Subject: Fw: Fw: sursound: The pinna and Ambisonics/cross post
From:    Peter Lennox  <peter(at)LENNOX01.FREESERVE.CO.UK>
Date:    Tue, 24 Oct 2000 14:40:42 +0100

This bypassed the list, so I've forwarded it
----- Original Message -----
From: "Eckard Blumschein" <Eckard.Blumschein(at)E-Technik.Uni-Magdeburg.DE>
To: "Peter Lennox" <peter(at)LENNOX01.FREESERVE.CO.UK>
Sent: 23 October 2000 16:52
Subject: Re: Fw: sursound: The pinna and Ambisonics/cross post


> Dear Peter Lennox,
>
> At 14:04 23.10.00 +0100, you wrote:
> Most of the world's
> >audio engineers proceed on the assumptions mentioned below,
> >namely that humans are able to more accurately locate a sound-source when
> >that source contains significant energy at below 1000Hz.
>
> I am convinced: Energy does not matter much due to the cochlear amplifier,
> properties of the neurons, etc.
>
> The research
> >mentioned below is also used to support the argument that sound sources
NOT
> >containing 'low frequencies' are correspondingly difficult to locate.
>
> Look into Buser and Imbert "Audition" 1992 and Fastl "Psychoacoustics"
1999
> for some real reasons of poor lateralization of pure tones above 1 kHz.
> Localization also includes elevation estimate. Narrow-band sound at 8 kHz
> is perceived as coming from above.
>
> From
> >personal experience, whilst I might well agree in the special case of
sound
> >generated by artificial devices (speakers), such as electronic tills,
mobile
> >phones, etc, such devices are ( from an evolutionary point of view)
> >comparitive latecomers, and can be considered 'minority' special case
> >audible objects. In the wider sense of the audible objects to be found in
> >real environments, it does seem to me personally that there is no sense
in
> >which Lf facilitates location-identification better than Hf; - quite
> >possibly the reverse. This is a problem I've puzzled over, on-and-off,
for
> >some years.
>
> You are quite right. It was Josef Manger who found out, that nearly all
> loudspeakers have a common drawback. They respond to a step with striking
> oscillations. If there are two (stereo-) loudspeaker in the room, then the
> listener must have equal distances to the both in order to not
> predominantly locate the less distant one because of the precedence
effect.
> J. Manger also gave explanations why "the Manger" is more natural. Indeed,
> a step-like click is a natural sound that is most important for survival.
> Look at www.manger-msw.com.
>
> >Is anyone aware of specific (and recent) research on this subject, or
> >theories which incorporate perception-as-related to 'real environments'
> >which speculate in this area?
>
> I do not know what you are considering recent and what to be research.
> There are high quality papers about bats. They echolocate in the range up
> to 150 kHz. I stated this year (in German) that even the human performance
> in localization exceeds the 20 kHz limit. It requires a higher resolution
> than achievable with 40 kHz sampling. Admittedly, this originally refers
to
> high binaural phase precision at low frequency. However, I would like to
> speak of temporal disparity (just a few microseconds for humans,
> nanoseconds for bats) instead.
>
> May I ask for a reply if there are people who made similar experiences, or
> someone can possibly otherwise contribute to the issue?
>
> Eckard Blumschein
>
>
>
>