i've done an exp where i have a signal generator connected to a speaker. It's then passed through a soundproof box which i made with cardboard with corrogated cboard lininig. I then have carboard barriers for the sound to pass through. The sound reaches the mic whcih is connected to a CRO. I will then calculate the attenuation
I have found that the 1st barrier makes the biggest difference, and that the attenuation just gets less and less after that. Do you agree with this, and do you have any comments about the experiment?
Many thanks
2006-10-13 22:36:16 · 4 answers · asked by muhammaddarwish 2 in Science & Mathematics ➔ Physics
well done fantastic. I think you are being wasted on here....you r making a statement rather than a question
2006-10-13 22:44:13 · answer #1 · answered by flymetothemoon279 5 · 0⤊ 1⤋
the attentuation will be geometric, by which i mean proportional to the signal.
To calculate that, put all your numbers into decibels rather than raw amplitude (volts on the CRO, whatever). I think the formula is 20*log(V2/V1), where the log is to base ten. The alternative formula is 10*log(V2^2/V1^2) which works out as the same thing. This assumes the mic is the same mic for each measurement. V2 is your volts after the barrier, V1 is your volts before the barrier.
Then you will find that the attenuation of each barrier is different only to the extent that the barriers (and their housings) are different.
As the sound gets quieter and quieter, errors will become more significant, so comparing barrier 27 to barrier 28 will probably yield only garbage.
2006-10-14 05:46:54 · answer #2 · answered by wild_eep 6 · 0⤊ 0⤋
Dear Muhammad,
I think that:
if your first baffle has a similar attenuation as the other walls of the box in which you have placed your microphone then the sound will also pass through the other 5 walls of your box at a comparable level (flanking sound).
Then putting more layers to attenuate the sound will not affect the readings that you obtain in the way that you would hope and expect.
This 'flanking' sound makes these experiments difficult to do, and you may be forced to make a concrete box to perform your experiment!
2006-10-14 05:51:46 · answer #3 · answered by Rufus Cat 3 · 0⤊ 0⤋
Does the position of the first barrier with respect to the speaker make a big difference?
Does the frequency of the noise that is made make a difference?
These are some of the other things you might want to have a look at while you have your experiment set up.
Best of Luck - Mike
2006-10-14 05:44:53 · answer #4 · answered by Anonymous · 0⤊ 0⤋