DTQWT mkII cabinet construction, pics and comments
Copyright 2010 Troels Gravesen
Updated Nov 2011

Cabinet drawings

Assembling cabinets

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 diameter.
30 mm Baltic birch (21+9 mm) was used for front panels. 50 mm front panel fillets were made from solid maple wood.

You don't have to make front inner panel like seen on the full drawing. The above is perfectly OK.

The front panels
Routing Baltic birch takes a fresh, razor-sharp router bit.

Solid maple used for fillets. Strips made from mahogany.

Routing for bass drivers
Routing 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 you're safe.

When 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 fastening.
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.

Cabinet damping:

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 drawing.

Front chambre behind JA8008 driver:
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 drivers:
Add felt to internal panel and on sides as seen on drawing.
Fold 23 x 100 cm 25 mm polyester damping and add to bottom of rear chambre as seen on drawing.

Total damping materials for two cabs:
- 2.0 sqm 8 mm grey Jantzen Audio felt.
-1.5 sqm 30 mm Jantzen Audio acoustilux.

Approx. measures for felt damping materials, in total 2 m*m.

Felt material added to front chamber, 50 cm from top of front interior panel. Glue and staples are used to keep things in place.
For the 30 mm polyester damping only staples are used.
Pics taken before the 10 mm felt material was available.

Half-fold 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 needed.

Left: 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.

Cab feet

Found these at a local diy home market: Total price < 15 US $), that is:
Spend money where it counts! This works perfect.
The final cabinets must be 30-45 mm above floor level!

Crossover mounting

Left: 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 panel.

Front driver crossover in place at front internal panel.

Secure driver leads

Secure leads from drivers like seen on photos. Ripped terminals are a real pain! Wires used are silver plated copper in teflon.
here how you fasten the waveguide to the tweeter.


Please read here: http://www.troelsgravesen.dk/DTQWT_tweaks.htm

Damping of rear bass drivers

Happy building

By 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!

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