Re: Listening to TC?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

Hi Malcolm,

        I don't think it does drop off. I think that coils should have many 
interesting "sounds" beyond human hearing range, which is why I'm trying to 
find the devices/references/parts to transform them into the audible range. 
The trick is to do it on limited income with home-brew equipment.

Matt D.

In a message dated 6/22/03 9:46:19 PM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:



>Original poster: "Malcolm Watts by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
>
>Hi Matt,
>
>On 20 Jun 2003, at 7:33, Tesla list wrote:
>
> > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
><Mddeming-at-aol-dot-com>
> >
> > Hi All,
> >
> >         We all know that spark gaps and streamers make some pretty awesome
> > sounds, but what about "ultrasounds"? These would be sounds from 15KHz on
> > up to the resonant frequency of the coil. This question is prompted by the
> > following: Last night, a bat got into the instrument/people section of the
> > lab. (The TC section is inside a grounded 10ftx10ftx8ft cage). With the
> > coil running, the bat ran into the wall the way a bird or insect will beat
> > against a window trying to get out. I turned off the coil and it
> > immediately turned around and flew back out the door which was only open
> > about 5 inches.  Makes me think maybe the coil was making sonar-jamming
> > noises. Of course, it could be pure coincidence.
>
>Why should the noise suddenly drop off at the limit of human hearing?
>;)
>
>Malcolm