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 > > > >

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Electrical Engineering Dept., Columbia University