On 2013-07-09, at 7:00 AM, [email protected] wrote:
> Date: Mon, 8 Jul 2013 20:52:45 -0400
> From: Bob Moriarty <[email protected]>
> To: [email protected]
> Subject: Stus-List Anti-Barnacle Waves - Was: Music in cockpit
> Message-ID:
> <CAM7ccY+Vhh9S8PUENZhB=k60ttpqmpdktzux1wrrbktpdq0...@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Professor Dreuge & Any Audio Engineers,
>
> Some of the abstracts in your link mention 23 kHz as a sort of sweet spot
> for barnacle repulsion. The spec sheets on the sound exciters all specify
> an audio range with the upper limit at 20 kHz - which is the upper limit of
> audio perception by humans.
>
> I'm an audio newb with a tin ear. Is it likely the sound exciters - or most
> any speaker for that matter - could produce output at 23 kHz? Would it be
> simple to create a CD with a 23 kHz sound track that could be played
> through a boat's sound system (to sound exciters attached to the inside of
> the hull)?
>
> I have more dumb questions for later.
>
> Bob M
> Ox 33-1
> Jax, FL
Hi Bob,
I don't know how scientific or specific barnacle-repellant audio frequencies
are… but quite apart from sourcing other audio components (amp, speakers)
having fidelity beyond the typical human hearing range, it is impossible to
imprint a CD with a 23kHz signal. The definition/resolution of CD audio
decreases towards the high end and tops out at 22.05 kHz at which point a pure
sine wave at that frequency would be recorded/reproduced as a two-data-point
wave - a square wave ("Over-sampling" would smooth this out somewhat but would
not produce a higher tone). On the other hand… I'm sure if the barnacles are
sensitive to these frequencies a square wave would piss them off more than a
pure tone.
or there is something like this:
http://www.americanpiezo.com/standard-products/ultrasonic-cleaning-transducers.html
Or turn-key system for $1400!
http://www.ultrasonic-antifouling.com/
Phil Strong
C&C 24 Aeolus (no stereo, no ultrasonics, just a melodica)
Little Current, Ontario
_______________________________________________
This List is provided by the C&C Photo Album
http://www.cncphotoalbum.com
[email protected]
