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Chu & Warnock’s long term speech
data, together with that for a 4128C head & torso simulator (HATS) could be
useful if you do not already know about it – see http://irc.nrc-cnrc.gc.ca/pubs/rr/rr104/rr104.pdf For a simple comparison, we converted
these data to directivity index (DI), and compared to our measurements of a
head-sized loudspeaker (NTI Talkbox). Up to 630 Hz third oct band, the DI
values of humans, HATS and NTI Talkbox are similar (mainly around 2 to 3 dB),
with the talkbox becoming increasingly directional at higher frequencies.
Roughly speaking, there is about a 3 dB difference in directivity index between
800 Hz and 4000 Hz 1/3-oct bands, and a much larger difference above that. I
expect similar results would occur for head-sized loudspeakers with similar
diameter drivers (about 800 mm). We did some other tests varying mouth
aperture on a HATS, which significantly changed directivty at some frequencies,
but did not change measured Speech Transmission Index values in three normal
rooms. The effect of directivity (based on theoretical modeling) should be
maximum at somewhat less than a critical distance, which in many situations is
too close to be of consequence. Cheers Densil From: AUDITORY -
Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Jose Almagro I think every loudspeaker of the same size a
human head has would comply. Norsonic recommends using a Best
regards. 2009/3/4 Tony Miller <antonio.miller@xxxxxxxxx> Suggesting a head and torso simulator (HATS) might be overkill on your
budget if you are just interested in getting the directivity of an average
human mouth. On Wed, Mar 4, 2009 at 11:10 AM, Pang <sound08@xxxxxxx> wrote: Dear List |