Wayne Parham Messages: 18756 Registered: January 2001
Illuminati (33rd Degree)
I agree about checking into bandpass boxes. They might be smaller and could provide the SPL needed. On the other hand, if he doesn't need a large duct area then 5.5 feet could be folded into a pretty compact box. Could be six one way and half a dozen the other on overall cabinet size. Definitely couldn't get a real basshorn down to size but maybe a one note tuned pipe could be made pretty small. I think it would be worth looking at both options, Helmholtz resonators and quarter-wave pipes.