Anti fouling could be easy. All we have to do is get the Cajuns here in 
Louisiana to develop a good recipe for barnacles.  It will probably start with 
a roux and use a lot of spices. Once the recipe becomes popular, there won't be 
a barnacle to be found!

Dennis C.
Touché 35-1 #83
Mandeville, LA

Sent from my iPhone

On Jul 9, 2013, at 8:38 AM, phil strong <[email protected]> wrote:

> 
> 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
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