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Re: [AUDITORY] Who coined the term "head-related transfer function"?



Hi,

I think the first to publish a measured HRTF in a peer-reviewed journal is probably Francis M Wiener and Douglas D Ross, JASA 18, 401-408 (1946) "The pressure distribution in the auditory canal in a progressive sound field". In this study, not only did they measure the free-field transfer function, and recognize the amplification caused by the ingenious physics, they also addressed the significance of the recording point and demonstrated that the sound transmission along the ear canal does not depend on direction (in the frequency range considered).

A supplementary account was given by Francis M Wiener in 1947 JASA 19, 143-143 (1947), which was titled "On the diffraction of a progressive sound wave by the human head". This study further demonstrated the dependence of angle of incidence of the sound wave.

It has always surprised me, how few citations these papers have, comparing to later reports of HRTF measurements.

The understanding of the diffraction by ear, head and body predates these publications, thus it is not unlikely, that the term head-related has been used casually at this time. There are several relevant studies of human localization preceding Wiener and Ross' measurements, which all relate the transmission properties incl. diffractive characteristics of the ear and head to the nature of human localization. Later publications, incl. e.g. the work by Edgar A. G. Shaw and colleagues, focused on the external ear characteristics, and the term external-ear transfer functions was also used for transfer functions, which we today would probably refer to as head-related transfer functions.

H.-J. Platte and P. Laws used the term head-related stereophony (Kopfbezogene stereophonie) in their paper in Rundfunktechniches Mitteilung, 22, 22-26 in 1978, and H. Wilkins in Acustica 26, 213-221 (1982). The term kopfbezogene (head-related) was probably already widely used in the tonmeister community, referring to the binaural recording technique. My guess is that the scientific communities used the term in presentations and discussions, but that the lack of adequate definition required written communications to be more accurate in what transfer functions were reported.

Still, today, I don't find that the term head-related transfer function has an equally robust definition, as e.g. the free-field transfer function or the progressive wave definition. Strictly speaking, a free-field transfer function is measured in conditions, where the wave impinging on the individual is plane. We try to establish that in the lab with speakers at distance, thus any study that investigates the limits of this, or study distance dependence in the transfer functions within 1-2 meters, measure distance (and source) dependent transfer functions. The literature has many accounts of "distance dependent head-related transfer functions", which wouldn't make sense, if we accept the plane progressive wave definition. But because the transfer function is measured in much similar conditions as the free-field transfer function, and since it is something "head-related" it makes sense to refer also to such transfer functions as "head-related". This also suggest that the term head-related transfer function is not unequivocal, and has maybe never really been coined.

I have also come across presentations that refer to the "earphone head-related transfer function", which is an even vaguer definition for the in-situ measurement of an earphone's response. For the majority of the HRTF scientific community, I wouldn't expect this to be an acceptable term, but it is intuitive to refer to this as a head-related (it is measured on the head, and its a transfer function).

I guess that head-related is intuitively and de facto a term, which we can't assume to be used only for the progressive plane wave transformation of the ear, head and body, which most of us consider to the head-related transfer function. Yet it seems still necessary to be accurate, whenever using the term. Many published "HRTFs" have arbitrary levels, and cannot be the free-field pressure ratios, although they display some of the distinct features (peaks and dips). Some don't even approach 0 dB at low frequencies, which the real free-field transfer function always do. And graphics showing the HRTF always seem to show a source close to the head (trying to save space in the illustration no doubt).

Best, Dorte.

On 18-02-2018 15:31, Stephan Paul wrote:
Dear all,

Kuerer,, Plenge and Wilkens (who worked together in Berlin)  wrote in their 1969 AES paper:  ``It has been shown by Blauert (7) that differences in the frequency function of the transmission factor when hearing form different directions...''  

@InProceedings{Kuerer1969AES,
  Title                    = {{Correct Spatial Sound Perception Rendered by a Special 2-Channel Recording Method}},
  Author                   = {Kürer, R. and Plenge, G. and Wilkens, H.},
  Booktitle                = {Proc. of the 37th AES Convention},
  Year                     = {1969},
  Note                     = {paper 666},
}

Reference 7 is Dr. Blauert's PhD Thesis. 

2018-02-17 16:01 GMT-02:00 Richard F. Lyon <dicklyon@xxxxxxx>:
Pierre found me a copy of a 1972 Plenge paper by the right title, here, not JASA:
http://www.ingentaconnect.com/content/dav/aaua/1972/00000026/00000005/art00003
Plenge, Georg. "On the problem of “in head localization”." Acta Acustica united with Acustica 26.5 (1972): 241-252.

It has lots of head-related ("kopfbezogener"), but not anything that looks like HRTF.

Head-related stereophony was a term already in use since 1971 at least, e.g. in Damaske, P. "Head‐Related Two‐Channel Stereophony with Loudspeaker Reproduction." The Journal of the Acoustical Society of America 50.4B (1971): 1109-1115.
Or "head-oriented stereophony" as was probably an alternative translation in Plenge's 1972 paper at
http://web.arch.usyd.edu.au/~wmar0109/DESC9090/old/BechZach_doc/AES_papers_doc/Plenge+Romahn72.pdf

The earliest HRTF I can find is 1975:
http://asa.scitation.org/doi/abs/10.1121/1.1995200
Yorifuji, Y., M. Morimoto, and Y. Ando. "Effect of training in sound localization in the median plane." The Journal of the Acoustical Society of America 57.S1 (1975): S37-S37.
Just an abstract of a poster; the other 1975 Google Scholar hits are false positives: other abstracts on the same page.

If Plenge actually coined the term, it would be good  to find that. 
Pierre, maybe try this one in 1973, which Google says contains kopfbezogener:
http://www.ingentaconnect.com/content/dav/aaua/1973/00000029/00000005/art00004
Dick





On Fri, Feb 16, 2018 at 10:31 AM, Pierre Divenyi <pdivenyi@xxxxxxxxxxxxxxxxxx> wrote:
Hi all auditories,

I thought Jens Blauert would be the best equipped to reply to this question. Here is his answer, in German and in Google-translate-English (=a peculiar English dialect).

Enjoy,
Pierre
========

Hallo Pierre --
Es war Georg Plenge (erlebt noch in Berlin) in einem JASA paper ca. 1972.
Wurde von Dennis Mc. Fadden reviewed. Ich hatte in meinem Buch "Außenohr-Übertragungsfunktion"
(external-ear transfer function) verwendet, aber HRTF hat sich durchgesetzt, obwohl falsch.
Was heißt denn "related"? Es IST die Übertragungsfunktion des Kopfes bzw. Ohres! 
Das Plenge-Paper müsste
ich mal raussuchen. Die JASA-Bände sind in Bochum.
Es ging dabei um Im-Kopf-Lokalisertheit bei Kunstkopfsignalen -- oder so ähnlich.

-- Gruß, Jens

=============
Hello Pierre -
It was Georg Plenge (still in Berlin) in a JASA paper circa 1972.
Was by Dennis Mc. Fadden reviewed. I had in my book "outer ear transfer function"
(external-ear transfer function) used, but HRTF has prevailed, although wrong.
What does "related" mean? It IS the transfer function of the head or ear!
The plenary paper I would have to raussuchen. The JASA volumes are in Bochum.
It was about in-head Lokalisiertheit artificial head signals - or something like that.
-- Greetings, Jens

==============

On 2/15/18 6:46 AM, Marc Schoenwiesner wrote:
Dear all,

does anyone know who coined the term "head-related transfer function"? The first mention in a paper (as far as I have been able to determine) is by Frederic Wightman and Doris Kistler in 1988, but they write: "...the free-field-to-eardrum transfer function (sometimes called the head-related transfer function, or HRTF)...", which sounds like there must be an earlier source.

Best,
Marc

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