Way ahead of you. Made a simple crummy model, because I needed it yesterday.
See this post:
http://www.changstar.com/index.php/topic,1028.msg32777.html#msg32777It's an attachment to a speaker made to actually emit sound, not receive it, but a similar method could be used to make a synthetic head. The size is quite a big one, but still possible. I've seen people with slightly bigger heads still.
The rags are actually the dampening. They work extremely well at low frequencies, so the resulting mouth stream is highpassed, counteracting the proximity effect somewhat (but not completely). It can be linearly compensated reasonably easily, mostly there is too long resonance still due to a cheap speaker, but REW can bring it to near perfection with just 6 peaking eqs, mostly trimming midbass and bumping 6k up.
Reasonably low nonlinear distortion due to this - measured with REW's RTA function and ECM8000 as around 0.1% D2 over the Behringer C50A speaker's baseline, which isn't that great either. Polar characteristic is very similar to real mouth, I haven't measured that though, just gauged it with ears. No anechoic chamber for that measurement.
I'll make a better version for a true HATS dummy lookalike, except prettier.
As amusing as dousing someone in silicone is, that is not necessary.
Cellophane is also not necessary - use a demoulding compound, water with soap or watered down wax, just don't forget to seal the air tubes with e.g. scotch tape.
Simpler way:
- Get a gypsum or plastic skull. You can use cosmetic plastic cheekbones instead.
- Use two bowls to cast lower and upper half of the mouth as well as back of the head in silicone.
- Put the skull in.
- Fill the necessary parts with PU foam or ballistic gel if you feel like spending more.
- Cut out (or fill before putting PU/gel in) nasopharyngeal (nasal) cavity.
- Attach some nose
- Mould some ears from polyclay (sulfurless is recommended)
- Put in fake or real ear canals with the right volume, such as 1.2cc
- Add fake silicone lips. Name it Jenny.
- Keep on rockin'!
Have a peek of our measurement "setup" for taking acoustic echo samples. Please excuse the crude method of attaching it to the speaker.
Note: this is confidential, don't get those nasty buggers lawyers on my ass.
The output was compensated with REW (generating impulse response) and SIR v1 was used to apply the filtering to the mouth signal.
The room is not anechoic to simulate real conditions. The other end wasn't pictured by me, but it lacks the head as it's not as critical there to have correct polar and reflection characteristics.
