Loudspeaker Designs and Articles for the DIY Enthusiast
The Alpair 10P is housed in its separate sub-enclosure. An 8" sonotube wedged inside the rectangular space. There are several sizes of 8" sonotubes so
they can nest inside each other for shipping. Pick the smallest one as the rectangular space is 7.5" x 7.5". The advantage of the sonotube cylinder is to
eliminate standing waves from the sides of the enclosure. The sonotube is lined with a 1" thick piece of foam. The rear of the enclosure, open through the
6" hole has a 5" to 6" plug of foam to attenuate all but the lowest frequencies from exiting the enclosure. The advantage here is little or no acoustic energy
is reflected back onto the alpair cone to smear or muddy the sound. So little escapes from the rear of the enclosure that only an inch or of space is
necessary between the rear of the enclosure and the front wall.
The SB midwoofers each have their own tapered transmission line which merge after the last bend to sum before the port. I recommend you start with 24 oz.
of polyfill stuffing in the first 2/3 of the line as shown by the yellow areas below. Leave the last third of the line empty, but certainly experiment with the
amount and position of the polyfill to find your particular sound. The interior panels used to form the transmission lines provide sufficient bracing. No other
bracing is required. The port is a Precision Sound 2" outside flare. No additional port tube is necessary. While I experimented with an inner flare, the bass
sounded best in this configuration.
Wayne built the enclosures out of 34" void free plywood, with a double thick front baffle. (See picture above) Certainly MDF is fine to use as well. The base
is separate and is used to house the crossover.
A FULL RANGE PROJECT
WITH BASS ASSIST AND