Forums

Acoustic Measuerment

Started by Major Misunderstanding October 31, 2006
There is such a thing as acoustic impedance. Is it possible to have sounds
that humans can hear that cannot be picked up with a mic? Could this be
because of a miss-match between acoustic impedances? ie a bit like an
amplifier and load.Would using a 'hood' a bit like an ear improve things?


M.



-- 
Posted via a free Usenet account from http://www.teranews.com

Major Misunderstanding skrev:
> There is such a thing as acoustic impedance. Is it possible to have sounds > that humans can hear that cannot be picked up with a mic?
Yes and no. "Yes" because it is perfectly possible that any given mic is tuned to a frequency range or sensitivity such that it does not record sounds a human can hear: An ultrasound transducer does not record the 0 - 20 kHz range, a hydrophone in air would not record anything but the loudest explosions. "No" on a more principal level. If a acoustic sound exists (I am deliberately excluding "voices inside my head") and the human ear can detect it (note the term "detect"; not "recognize" or "classify"), a microphone can be designed that also detects the same sound. Rune
Rune Allnor wrote:
> Major Misunderstanding skrev: > >>There is such a thing as acoustic impedance. Is it possible to have sounds >>that humans can hear that cannot be picked up with a mic? > > > Yes and no. "Yes" because it is perfectly possible that any given mic > is tuned to a frequency range or sensitivity such that it does not > record > sounds a human can hear: An ultrasound transducer does not record > the 0 - 20 kHz range, a hydrophone in air would not record anything > but the loudest explosions. > > "No" on a more principal level. If a acoustic sound exists (I am > deliberately > excluding "voices inside my head") and the human ear can detect it > (note > the term "detect"; not "recognize" or "classify"), a microphone can be > designed that also detects the same sound. > > Rune >
You didn't answer his first question (ended with a "." not a "?" ;/ Yes, there is a concept that may be called "acoustic impedance". Speaker housings are essentially "acoustic impedance matching devices". Does it have anything to do with second question. ~no.
Richard Owlett wrote:

> Rune Allnor wrote: > >> Major Misunderstanding skrev: >> >>> There is such a thing as acoustic impedance. Is it possible to have >>> sounds >>> that humans can hear that cannot be picked up with a mic? >> >> >> >> Yes and no. "Yes" because it is perfectly possible that any given mic >> is tuned to a frequency range or sensitivity such that it does not >> record >> sounds a human can hear: An ultrasound transducer does not record >> the 0 - 20 kHz range, a hydrophone in air would not record anything >> but the loudest explosions. >> >> "No" on a more principal level. If a acoustic sound exists (I am >> deliberately >> excluding "voices inside my head") and the human ear can detect it >> (note >> the term "detect"; not "recognize" or "classify"), a microphone can be >> designed that also detects the same sound. >> Rune >> > > You didn't answer his first question (ended with a "." not a "?" ;/ > > Yes, there is a concept that may be called "acoustic impedance". Speaker > housings are essentially "acoustic impedance matching devices". > > Does it have anything to do with second question. ~no. >
mea culpa *MEA CULPA* I should practice "read first -- type later" ;<