Subject:
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Re: NXT sound sensor characteristics
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Newsgroups:
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lugnet.robotics, lugnet.boats
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Date:
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Sat, 28 Feb 2009 14:46:53 GMT
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Viewed:
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20622 times
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Thanks Brian
> snip.. The summarized results (over a lower range of
> frequencies) are here:
>
> http://www.brickshelf.com/cgi-bin/gallery.cgi?i=3348152
>
> My conclusion was the sensor can be used to distinguish fairly pure tones below
> roughly 1 kHz (below 1 kHz, there's a nice distinguishable difference between dB
> and dBA modes), but not above that..snip
Your excellent graph shows that you tried to maintain the sound pressure
constant. We did the inverse in the last graphs, where we tried to draw the
curve for a constant NXT sensor value.
We also repeated the experiment, and this time, besides the measurements, we
payed attention to the sensation of loudness... and we were amazed to see that
around 3kHz, the sound sometimes has to be louder, sometimes weaker, in order to
maintain the constant 20 NXT-dBA. We sweeped over the range and the value droped
and grew at neighbour frequencies.
This leaves us puzzled. It would be a great thing, if someone verified this.
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Message has 1 Reply:
 | | Re: NXT sound sensor characteristics
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| (...) Since I was doing this all manually, it was by far the easiest. I realized that a better way would be to vary the signal generator level at each frequency, but often when trying that I simple "maxed out" the reported level from the sound (...) (15 years ago, 28-Feb-09, to lugnet.robotics, lugnet.boats)
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Message is in Reply To:
| | Re: NXT sound sensor characteristics
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| (...) anything interesting at 3 kHz... perhaps because I didn't go that high (oops). To figure out the frequency response I did it manually: I borrowed a signal generator and speaker from the university, as well as a sound meter, and then simple (...) (15 years ago, 28-Feb-09, to lugnet.robotics)
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