Re: [PSUBS-MAILIST] I NEED A SPEAKER!

[TeslaTony@aol.com]

In a message dated 11/29/00 11:30:13 AM Pacific Standard Time, 
vulcania@interpac.net writes:

> Does anybody know where I can get a submersible 12 Volt underwater 
> loudspeaker?  I want to hide a public address system under the aft-deck of 
> the NAUTILUS, so I can talk to my support crew more easily (yelling is a 
drag,
>  and the spectators don't understand).  It would also be cool to blast out 
> sound effects like that "turbine whine" the Disney NAUTILUS made in 
LEAGUES, 
> and such.
>  
>  Gotta be fairly small (about 8 inch diameter at the horn mouth, maybe?) 
> fully waterproof, and if I didn't have to take a second mortgage out on the 
> house, that would be cool, too!
>  
>  Or, and ideas on how to make one?
>  
>  VBR
>  
I've never tried this before, but I think that a peizo disc with some 
cellophane wrapping material (the type of stuff that you wrap a batch of 
cookies up in) around it to keep the water off so it doesn't short out. There 
might be a problem with pressures at different depths causing interference 
with the electrical signal, but unless there is something I overlooked you 
should be able to take care of that problem just by shorting it out every 
once in a while (about every time you change the pressure exerted on the 
disc).

Bonus: Peizo discs not only convert electrical energy to mechanical energy 
(electricity to sound) but will also do the reverse, effectively becoming a 
microphone.

Anthony