single-impulse wav file
image of impulse
synthesized tube impulse
image of synthesized impulse
see the impulse images side by side
The tube I used was of the largest diameter available (approx. 2.5inches). the
length was 56cm. Since there will be, though miniscule, a constant error
between each peak, the more peaks we include, the less the effect of the error.
Thus, I took into account the time between 25 peaks, the first from .014s and
the last ending at .106 seconds. Thus, the total time taken is .092sec, and
the total distance traveled is .56x2=1.12m*25=28.125m. (we multiply the length
of the tube by two since after the first impulse, the sound must travel back up
and down the tube again for the mic to pick up the reflection.) So, by these
numbers, the speed of sound is 28.125m/.092sec = 305.7m/s.
To synthesize the impulse, the values I used were .0037 for the echo delay, and
.93 for the attenuation. I also had to change the length of the original sound
file to .226 seconds instead of the default .1
