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.

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   Speakerlab W1208R

  Physical length ~8 ft     Sd 580 cm2 (90 in2)
  Physical fs at 1/4 wl (no stuffing) 35 Hz     Vas 210 liters
  Begining cross section 188.5 in2     Fs 16 Hz
  Terminus section 81.25 in2     Re 5.7 Ohms
  Taper 2.1 : 0.9 Sd     Qms 2.39
  Stuffing Dacron     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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