Posted by Gerald J. on July 12, 2001 at 19:57:45:
In Reply to: Re: Re: Re: Yet another change to The Tuba Sound posted by Rick Denney on July 12, 2001 at 11:12:05:
One way you might detect room effects is to move tuba and microphone a half wavelength in all directions and see if the harmonic patterns change anywhere during the motion. I'm suspicious that the 10 dB drop one tuba harmonic showed was because of a cancelation between a direct wave and a reflected wave off a wall or floor.
If the spectrum stays the same with each tuba and microphone moved through a 1/2 wavelength radius sphere, then I might be able to accept the room isn't affecting your measurements.
Acoustical response numbers are easy to acquire, but extremely difficult to repeat without a whole lot of care. Here, I'd go use a corn field, if the corn wasn't growing too fast or the wind rustling the leaves. The corn would be a good sound absorber. But growing corn makes noise these warm days without any wind.
Gerald J.