A horn loaded sub in a car? Traditional theory says horns are too
big to fit in a car, but traditional theory dates from the 1940's. That was
then, this is now, and now there's AutoTuba, a bass horn that can be loaded
with an eight or ten inch long throw woofer.
Using a driver that small means you can get a full seven foot long horn in
a package small enough (14x15x32 inches) to fit in your trunk with room left
over. But the small size doesn't mean a small sound. The AutoTuba easily
beats a commercial subs, even in the home. Here's what builder Bruce Klemz
said about his:
"Wonderful, way better than I hoped. Smooth, deep bass. Much better than
the 15" ported box they replaced - very musical. Used in home, bass this good
would be wasted in a car!"
Check out this SPL chart, comparing the in vehicle response of the AutoTuba,
loaded with a $35 eight inch woofer, to an average 12" commercial sub:
The AutoTuba runs on average 10dB hotter than the traditional sub, and that
means it sounds twice as loud. But it won't cost you twice as much. You can
build your AutoTuba for less than $100, complete.
AutoTuba can also be built in a taller 20" x 22" x 15" version, for spaces
where a higher box is a better fit- like in between the seats of a van.

AutoTuba also may be used as a home or pro-sound sub, where Tuba 18 is not
quite enough but Tuba 24 and Table Tuba are too much.
Construction Degree of Difficulty: 5
Performance Quotient: 7
Equivalent Retail Value: $ 599
Plans are $14.95, delivered within 24 hours as email attachment in MS Word format. 13 pages, 17 photos, 18 diagrams. PDF available on request.
Also includes an active 3D program so that you can view the cabinet in any orientation with X-Ray vision!