Building a curved speaker with constrained layer damping - 3

Project intro >

Part 2 >

Attaching bracing and bottom:

The box lining is attached in place, along with the vibration damping (either bitumen or rubber sheets) prior to assembly. Access will be limited later. A staple gun comes in very handy here. 

Gluing first curved segment:

Many clamps are used, not only to apply pressure but also for adjustment. The use of CNC panels does not make a good result certain. If not correctly assembled, the box may not end up square. The diagonal clamp in this picture is used for adjustment.

Long clamps are required in a project like this. I'm using 1m clamps here:

 The glue ooze is expanding polyurethane glue. It's expensive and harder to work with, but necessary in certain places. Why is it harder to work with? Even getting it out of the bottle needs more effort, firm pressure is required. Gloves must be worn, since it's very difficult to clean off your hands. If you get it on your hands, washing immediately will usually not get it all off.

Dowells added as bracing and the top also goes on:

Building a curved speaker with constrained layer damping - 2

Part 1 >

Test fit of curved segments together with a constrained layer damping sheet:

Not yet attached ...

 Clamping together:

CLD (Constrained Layer Damping) curved segment: 

Ribs are modified so they fit together better:

Priming the bitumen:

Front baffle stoppers - these hold the ribs into position firmly.

Vibration damping applied to the internal surface of the front baffle.

Absorption applied.

First layer of bitumen over primed MDF:

Top walls clamped whilst the glue sets, bitumen applied also. Masking tape is there to keep the bitumen off the middle, where a dowell will be used as bracing.

First layer of bitumen over the first assembled CLD composite segment:

All layers of bitumen applied:

Building a curved speaker with constrained layer damping

This is a challenging custom build for a client who wanted a curved box with constrained layer damping on the side panels. A difficult combination!

 Front baffle. Fixing the depth of holes for the neo magnets. Grille will be attached by concealed magnets.

Bottom panel which holds the down firing port.

 Applying bitumen to internals of some of the panels.

Gluing base panels together.

 Bottom panel accommodates a panel that screws in. This allows access to the port and crossover which will be installed in the base. 

The thin segments here nest better for machining, but in hindsight it wasn't worth the extra trouble just to save on MDF in a project that unavoidably wastes a great deal of material. 

 Ribs about to be glued together: 

 Assembling rib sections. Dowells lock them together and align the ribs.

 Outside ribs:

 Ribs temporarily placed over bottom of speaker:

 You can see burn marks at the centre of each rib, where the tool starts and ends each cut. A compromise must be chosen in setting up the CNC tool paths. In future it will be done differently (this is the first box with more to follow). 

The holes for the dowells weren't quite big enough, so a custom tool was made to bore them concentrically.

Rib segments (20 per speaker) are clamped after assembly.

 All segments glued together:

Sanding the internal surface to ensure a tight fit with the rubber sheet that will be used as the constrained layer:

 Segments after sanding:

These are simply for one box!

Cinem8 veneer

Cinem8 with tassie oak veneer and raw grille on front baffle.

More about Cinem8 >

PSE-144

First release due in March.

HE2 now available

HE2 is now available in kit and finished version, with a choice of veneers.

This speaker is hand made to order here in Australia, with a choice of veneer in the finished version. Please contact us to discuss your purchase.

PSE-144 Launch Coming soon

Announcing the imminent launch of PSE-144. This is a point source horn that features a custom designed horn combining the outputs of multiple drivers into an ideal point source. 

Features:

• A true point source where multiple driver outputs combine near the throat of the horn
• Constant directivity achieved without throat diffraction
• 80 degrees horizontal dispersion 250 Hz - 19k
• 60 degrees vertical dispersion 500 Hz - 19k
• High sensitivity: 103 dB 1W 1m 
• Easy load to drive: 8 ohms impedance
• Fibreglass elliptical horn
• 1" exit compression driver
• 4 x 4" dedicated midrange drivers

Coming soon

PSE-144 is about to be launched with an exclusive first run that has been offered to a limited number of DIY enthusiasts. Currently this product is being offered as a kit which requires the addition of a bass module operating below 250 Hz. In the near future it will be offered both as a DIY kit and as a finished product.