| Re: The Didj and infrasound... [message #1440 is a reply to message #1381] |
Thu, 01 September 2005 06:31  |
lunartick
Messages: 13
Registered: July 2005
Location: United Kingdom
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Junior Member |
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Hi,
Thanks for the link, I hadn't read it before. Measuring accuratly below 20Hz is very difficult, some mikes will see a signal down very low, but the efficency of the mike will be greatly reduced maybe 0.1% or less.
So it could just be that the small peak on the spectrum on that page (which shows a small peak at the infrasound end), could actually be a very big peak, but due to the inefficency of the mike it looks small.
It would be interesting to measure one with a proper infrasound meter, (very few of those exist), it would mean going to a lab.
Thinking about it of course your lips are actually vibrating at a very low frequency just a few HZ at times, so there certainly would be some infrasound produced, in fact one of the excepted ways of generating large volumes of infrasound is by pulsing a motorised fan at 20Hz or so, thereby creating a shockwave with a period of 20hz, (essentially a very low hum with high volume) and that is more less what your lips are doing in a digj!! pumping up the tube with low freqency and causing resonance in the tube.
hmmm.
Mark
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