[Sursound] KEMAR, Neumann, Zwislocki

[Eric Carmichel]

Hello Guilherme,
I have some insight regarding your question re KEMAR and the Neumann acoustical 
test fixtures/heads.
Briefly, KEMAR was designed with hearing science in mind. The torso was 
designed to approximate "average" human size (I think we have, on average, 
grown since the introduction of KEMAR). Additionally, the material from which 
KEMAR is fabricated has an absorption coefficient to match that of humans 
(clothed or not clothed??--will have to refer to Knowles Electronics for this 
info). KEMAR is generally equipped with two interchangeable ear sizes: Large 
and small. If you look at impulse responses obtained with a KEMAR (e.g., the 
widely used IRs that came from a MIT lab study by Gardner et al), you'll 
probably see in the info section which of the two ears was used. Internal to 
KEMAR, their are microphone clamps for 1/4- or 1/2-inch mics (two different 
clamps for each mic size). A pig-tail adapter allows two Bruel & Kjaer mics (L 
+ R) to fit within KEMAR's limited head space (getting into the mind of KEMAR 
is a tight fit?).
When making a recording using internal mics (not the same as mics proximal to 
the ears conchas), the resonant peak created by KEMAR's ear canals will have to 
be considered. The recordings with peaks work well with deep-seated earphones, 
such as EAR phones, that otherwise destroy the ear's natural canal resonance. 
Note: Earphones worn OVER the ears modify the natural resonance, but don't 
destroy it. One could argue that the (approximate) 6cc volume of circumaural 
headphones over the ears' 2cc volume will certainly change things a bit. 
However, the active drivers of headphones may result in a larger "equivalent" 
earcup volume that imposes less of a change than one might predict. (Analogy 
here: The B&K acoustical calibrator has a large equivalent volume despite a 
small physical volume--this large virtual volume minimizes error caused by mic 
placement in the calibrator.) Just be aware that mic placement, either in KEMAR 
or proximal to concha, will affect
 recordings at the very important mid frequencies.
Another thing about KEMAR is that it is designed to accomodate a Zwislocki 
coupler. Maybe it's more accurate to state that the Zwislocki couple was 
designed to fit inside of KEMAR. Anyway, the Zwislocki coupler mimics middle 
ear function. Briefly, it is mathematically equivalent in compliance,  mass, 
etc. of the middle ear (tympanic membrane, ossicles, ligaments, etc.).
If you wish to learn more about KEMAR recordings, I recommend a search for 
articles authored by Zwislocki, Mead Killion (of Etymotic Research), and 
others. One article by Killion is titled "Zwislocki was Right." A Google search 
for Jozef Zwislocki will reveal some very interesting information regarding 
human hearing.

Now for  the Neumann head: I believe this was designed primarily for 
high-fidelity, binaural recordings. I have listened to recordings made with the 
Neumann head (and IRs obtained via the Neumann head), but can't state whether 
these are significantly different from KEMAR recordings. Like many things, one 
has to consider the overall system: Recording and playback. I've heard KEMAR 
recordings that suck, and others that were fabulous. Why the difference between 
recordings? Not sure, as I didn't have all the details. Maybe getting 
recordings from the same venue and source would help, but I don't know of any 
direct A-B material for comparison.
I hope this info helps some. As usual, I'm writing off the cuff without any 
reference material, so please pardon any inaccuracies. At least the people 
mentioned above (Killion, Zwislocki) will reveal accurate and detailed info.
Best regards,
Eric C.
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Re: [Sursound] KEMAR, Neumann, Zwislocki

[Aaron Heller]

I'll add that the Neumann KU81 and KU100 dummy heads (Kunstkopf) are
designed to sound good over loudspeakers as well.  There's a paper by
Stephen Peus about this that you can download from Neumann  at


http://www.neumann.com/?lang=en&id=current_microphones&cid=ku100_publications

Look for  "Stephan Peus, 1985: "Natural Listening with a Dummy Head",
English, 6 pages"

Aaron Heller (hel...@ai.sri.com)
Menlo Park, CA  UA
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Re: [Sursound] KEMAR, Neumann, Zwislocki

[Stefan Schreiber]

Eric Carmichel wrote:

When making a recording using internal mics (not the same as mics proximal to the ears conchas), the resonant peak created by KEMAR's ear canals will have to be considered. 
 

So: Why are we actually < not > doing some "Kunstkopf" recordings with 
mics just outside the ear channels? (I believe nobody does this.)


Head-shapes and torsos should be far more similar than ear pinnae. If 
so, you would minimize the problem of very different HRTFs between persons.



Best,

Stefan



Now for  the Neumann head: I believe this was designed primarily for 
high-fidelity, binaural recordings.

I don't see any different aim than in the KEMAR case. (Would there be 
any difference to do some "real"/"correct" or "high-fidelity" binaural 
recording? Don't think so, but I am ready to learn... :-) )


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Re: [Sursound] KEMAR, Neumann, Zwislocki

[umashankar manthravadi]

i have. I have also done a few recordings using the mics mounted on my shoulder 
just where it joins the neck to create a kind of head shadow, without forcing 
me to walk with my head held unnaturally rigid. umashankar

i have published my poems. read (or buy) at http://stores.lulu.com/umashankar
 > Date: Sat, 30 Mar 2013 04:13:04 +
> From: st...@mail.telepac.pt
> To: e...@elcaudio.com; sursound@music.vt.edu
> Subject: Re: [Sursound] KEMAR, Neumann, Zwislocki
> 
> Eric Carmichel wrote:
> 
> >When making a recording using internal mics (not the same as mics proximal 
> >to the ears conchas), the resonant peak created by KEMAR's ear canals will 
> >have to be considered. 
> >  
> >
> So: Why are we actually < not > doing some "Kunstkopf" recordings with 
> mics just outside the ear channels? (I believe nobody does this.)
> 
> Head-shapes and torsos should be far more similar than ear pinnae. If 
> so, you would minimize the problem of very different HRTFs between persons.
> 
> 
> Best,
> 
> Stefan
> 
> >
> >Now for  the Neumann head: I believe this was designed primarily for 
> >high-fidelity, binaural recordings.
> >
> I don't see any different aim than in the KEMAR case. (Would there be 
> any difference to do some "real"/"correct" or "high-fidelity" binaural 
> recording? Don't think so, but I am ready to learn... :-) )
> 
> ___
> Sursound mailing list
> Sursound@music.vt.edu
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