Here 21 mm Baltic birch was used for side and
rear panels. Internal panels were 18m mm incl. bracings.
Rear panel was made 264 mm wide and rebated.
See drawing above. Bass drivers are 260.4 mm
30 mm Baltic birch (21+9 mm) was used for front panels.
50 mm front panel fillets were made from solid maple
You don't have to make front inner panel like
seen on the full drawing. The above is perfectly OK.
The front panels
Baltic birch takes a fresh, razor-sharp router bit.
Solid maple used
for fillets. Strips made from mahogany.
Routing for bass drivers
Baltic birch takes a fresh, razor-sharp router bit. Start routing to
e.g. 0.2 mm depth, then sand the edge. Proceed another 0.3 mm and then
using Eminence Deltalite II 2510 bass drivers, use min.
25 mm rear panel thickness as the Deltalites need 19 mm
rebate. Glue small
pieces of 10-12 mm plywood under screw holes for secure
Alternatively maintain 22 mm rear panel thickness and
route to 12 mm depth. This will leave some 6-7 mm foam
gasket above rear panel
level. Doesn't look bad at all.
Two types of damping materials are used in
the DTQWT construction:
Left: 8 mm felt. Right:
30 mm polyester damping material.
1. Green (drawing): 8 mm felt material.
2. Yellow (drawing): 30 mm polyester damping material/acoustilux.
Add felt to
sides of front and rear chambres.
Center chambre: No damping material is used here.
Top of cabinet: Add felt material as shown on
Front chambre behind JA8008
One layer of 30 mm polyester, 22 x 25 cm is
placed behind JA8008 driver.
Fold a piece of 20 x 30 cm 30 mm polyester, place at bottom of
front chambre as seen on drawing.
Rear chambre behind bass
Add felt to internal panel and on sides as seen
Fold 23 x 100 cm 25 mm polyester damping and add to bottom of rear chambre as seen on
Total damping materials for two
- 2.0 sqm 8 mm grey Jantzen Audio felt.
-1.5 sqm 30 mm Jantzen Audio acoustilux.
measures for felt damping materials, in total 2 m*m.
material added to front chamber, 50 cm from top of front
interior panel. Glue and staples are used to keep things
For the 30 mm polyester damping only staples are used.
Pics taken before the 10 mm felt material was available.
a piece 30 mm polyester damping (23 x 35 cm) cm as seen on photo and
fasten with staples.
Add 30 mm polyester behind JA8008 driver as
seen on photo and fasten with staples.
Add felt to top of cabinet, a piece of 24 x 50 cm is
Add felt to sides of rear chambre as
seen on photo. Felt reaches all the way down to the
bottom of the chamber.
Fold a 23 x 100 cm piece of 30 mm polyester and place at bottom of rear
chamber, see drawing.
Right: Ups....almost forgot the front chamber bracing...
still time to glue this in place.
The final layer of damping the top of side
panels. Approx. dimensions seen on drawing.
these at a local diy home market: Total price < 15 US
$), that is:
Spend money where it counts! This works perfect.
final cabinets must be 30-45 mm above floor level!
Believe me, this is the last time I mount terminals after
having finished the cabs! I suggest using a terminal
board that allows
access to the top (at the bottom) of the bass horn. Right: Bass crossover section in place at rear internal
driver crossover in place at front internal panel.
Secure driver leads
leads from drivers like seen on photos. Ripped terminals
are a real pain! Wires used are silver plated copper in
Read here how you fasten
the waveguide to the tweeter.
TWEAKING THE DTQWT
Please read here:
Damping of rear bass drivers
the way -
Baltic birch residues
makes a nice bonfire for your afternoon coffee - made from freshly
ground Arabica coffee beans.
Poor yourself a glass of a good twelve year single malt to celebrate
the occation. Enjoy!