Aha, thanks for that, Raimund. I tried it on a work computer running Window=
s 10, without much luck. I'll experiment with it tonight on a Windows 7 PC =
at home.
Raimund wrote:
> > I've tried generating high frequency test tones in Audacity on a PC, bu=
t the
> system doesn't seem to be able to reproduce them over about 20kHz. I don'=
t
> know if the limitation is the soundcard or the speakers. I've tried earph=
ones
> instead of the speakers, in the hope that a small driver can go higher, w=
ithout
> much improvement, so I suspect it's the sound card.
>
>
> Hi Peter,
>
> You need to adjust the playback sample rate on the Windows Control Panel
> (Hardware and Sound > Manage Audio Devices > Playback > Properties >
> Advanced. Select here 192 kHz. The sound cards in most computers support
> that rate for playback. If it still does not work, you might just try a d=
ifferent
> computer.
>
> You are correct about the earphones. Even the tiny internal speakers on
> cheap laptops and tablet PC's can reproduce ultrasounds well beyond 20 kH=
z.
> The sound levels that can be achieved at higher ultrasonic frequencies ar=
e
> however quite low. So, you probably have to put the bat detector directly=
in
> front of the speaker.
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