Posted by Rick Predictably Denney on July 26, 2001 at 15:57:34:
In Reply to: yet even more tuba spectra posted by Kenneth Sloan on July 26, 2001 at 15:29:51:
Cool. The spectrum for the low Bb is remarkably similar to the one I measured for the same note using the 621 F tuba. There are differences, e.g. the third overtone, but the overall shape is pretty similar.
The C graphic is really the D graphic, but you have probably already discovered that. The D graphic shows all the overtones but no fundamental for the 78-Hz low D. I'd bet that 78-Hz tone is acoustically dead in that room, possibly absorbed by some appropriately shaped object. I'd also bet that it still sounded like a low D, indicating that the fundamental is suggested to our ears and brains by the overtones more than by the actual 78-Hz wiggle. This is an interesting accident.
Rick "proud to see a fellow geek being kept off the streets" Denney