Yamaha DTXpress/DTXplorer/DTXtreme

On Wed, 6 Aug 2003 09:25:34 -0400, Creighton Higgins wrote:
>\ufffdHe set up a guitar amp with a frequency generator in the tunnel in an
>\ufffdeffort to find the tunnel's resonant frequency. Well, he found it.
>\ufffdSupposedly there were swaying vibrations all the way to the top of 
>\ufffdthe dorms and a squad of campus police arrived to end the experiment.
>\ufffdI have no idea what the frequency was that was arrived at-
>\ufffdbut it takes very little energy to excite a column of air if the 
>\ufffdfrequency is correct.

This is the theory behind vented enclosure loudspeakers. It's used to 
both control the excursion of the woofer cone and also augment the bass 
output by moving more air through the cabinet vent. You tune the box
volume and vent port to the speaker's low frequency cutoff you desire,
which limits the speaker's excursion.

It's also used in transmission line speaker design and the principle
behind how the Bose system you see all the infomercials about achieves
it's "amazing lifelike sound" from such a small enclosure and speaker
drivers.
hehehe...

Matt Pobursky