On Tue, Feb 19, 2013 at 05:49:37AM +1100, David Worrall wrote: > Does anone know of such a beast? > (I thought of putting the TetraMic in a plastic bag, but I'm not sure Len > would approve :-)
Don't know what Len will think of it, but putting a Tetramic (or any such mic) in a plastic bag isn't likely to produce anything usable. Basic problem is that the acoustic impedance of water is around 3400 times higher than that of air, so the water/air interface will reflect almost all energy. You need a transducer that is more or less matched to the acoustic impedance. > Or how one might go about building one... > Failing which, does anyone have a recommendation on a cost-effective > single-channel unit? Have a look at <http://www.aquarianaudio.com/hydrophones.html> Prices start at around $130. I know of one experimental underwater AMB mic using these - but can't tell much more. Most hydrophones (and certainly any low-cost ones) will be omnis, so the A/B processing will be very different from what is required for a normal tetra mic using directional capsules. If they are not omnis then calibration becomes a real practical problem, it requires underwater impulse response measurements which in turn require a calibrated underwater source - an expensive item. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
