Subject:
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Range of RCX sound production
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 18 Aug 2004 16:16:38 GMT
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Viewed:
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1074 times
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In the "what other weird questions can Brian Davis come up with", here's one
I've not been able to locate on any website (including the Mindstorms Internals
site), and I can't test it easily with my ear:
What's the frequency range for the RCX sound production?
By playing a tone and then increasing it till I lost the sound. It remains
loud & clear until about 5000 Hz (PlayTone(5000,100);), and then seems to get
softer, but is still audible at 7.3 kHz. Beyond there there's still sound being
produced weakly (to my ears) to 15 kHz, with a distinct "click" audible between
tones. Between 15 kHz & 17.3 kHz there is still a trace of sound, but very very
weak and (again, to my ears) atonal. Above 17.3 kHz, I hear only the "click"
between tones, and above 20 kHz this ceases abruptly. Note that usually I can
hear the tone put out by a TV without a signal going in (26 kHz? IMS, & it
probably doesn't), but the scan tone from a TV is rather loud (I don't hear it
that way, but measuring the audio power shows it's a "loud" source).
So, does anybody have a audio spectrum analyser handy, and can see just what
the RCX is putting out at these very high frequencies (it would be great to have
something like a graph of power vs. frequency).
The low end is easier - it seems to make sound (OK, a series of clicks) down
to right around 32 Hz, cutting off below that.
--
Brian Davis
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Message has 2 Replies:
 | | Re: Range of RCX sound production
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| Hi Brian, I find your question very interesting. I do not have an audio analyzer, but I have a few ideas so you can extend your hunt. I'm told that you can get software that lets you use your sound card as an oscilliscope. All you need is a (...) (20 years ago, 18-Aug-04, to lugnet.robotics)
| | | Re: Range of RCX sound production
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| Hi Brian, I examined the RCX ROM sound routine, and it provides a lower bound of frequency 31 (matches what your ears told you), and an upper bound of 20000 (also as you noticed). I'm not sure about the sound hardware, but you might be able higher (...) (20 years ago, 18-Aug-04, to lugnet.robotics)
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