AQA* Bass Box Dissected by Nick Huntington
This design is a single fold transmission line using a 12" Speakerlab W1208R. Both the speaker and the port load out the top. Stuffing with Dacron (density unknown) This design has an even taper, very simple construction, and 4 feet behind the woofer. Used with a Hafler DH200 (100 w/chan) or an SAE 2300 (150 w/chan) and an Energy "EAC" crossover. This has 24 dB/octave low pass 50 - 150 Hz, 12 dB/octave high pass 50 - 150 Hz, variable levels, phase, and bass boost. Requires a driver that can be mounted facing up. * Aardvark Quark Audio, Seattle WA/designed by David Ruether David has a web page detailing some of his hifi endeavors and has a picture of the big brother to this sub -- a TL with an 24" Hartley! Nick has suggested an alternate line folding for this design
Some comments I received from David: Using better-than-usual pillow-stuffing (some settles easily -- what I use is very long-fiber, and it won't stay crushed), I pull it out for minimum density, and carefully place bits of it for uniform low density with no gaps... the bottom baffles are a smoothly-curved piece of 1/8" Masonite... the whole thing was designed to come out of a single sheet of 4'x8' board, and to go together quickly and easily using carpenters' glue, with locating nails and tape to hold it together until the glue dried - these boxes could be built in a short time from commercially-cut pieces, and finished with a wood front and black Formica sides using only a router for fitting. The alternate line folding is similar to the BIG Bass Box design from The Amatuer Audio 2-1978 (the one in the photo is different, and somewhat smaller), but the TAA box adds more reflectors at the bottom and a center divider, and better-maintains line cross-section continuity.
Line Configuration   Physical length ~8 ft   Physical fs at 1/4 wl (no stuffing) 35 Hz   Begining cross section 188.5 in2   Terminus section 81.25 in2   Taper 2.1 : 0.9 Sd   Stuffing Dacron Plans	Speakerlab W1208R   Sd 580 cm2 (90 in2)   Vas 210 liters   Fs 16 Hz   Re 5.7 Ohms   Qms 2.39   Qes 0.50   Qts 0.41   Xmax 10.4 mm Cone is heavy ribbed paper, surround butyl rubber, frame very heavy stamped steel.
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