The enclosure for this speaker is a simple box of approximately 4.8 liters volume. Due to the size it does not need bracing and using 18mm MDF of equivalent results in a very solid and heavy little box.
Thirty minutes from my house is a specialty loudspeaker cabinet maker who produce the cabinets for many Australian loudspeaker companies, including Osborn Loudspeakers, called Aranmar Acoustics. Aranmar are also the primary distributors for Seas loudspeaker drivers within Australia. A phone call, a quick CAD and delivery of the timber and they were able to produce some great loudspeaker cabinet panels.
For these speakers I was looking for an environmentally friendly timber which could be used in place of MDF (people shouldn't be breathing formaldehyde) and which is easy to work with. I also wanted the benefit of having the raw timber look without having to veneer as I do not have the time nor the equipment to do a good job.
I stumbled upon the bamboo-ply idea from Nomad Audio who formerly used bamboo cross-ply products almost exclusively in their loudspeakers. This timber is extremely strong as there are three layers of bamboo joined together perpendicular to each other. The bamboo is supposedly grown to a mature state for harvesting in only 5 years so does not greatly impact the environment like some hardwood timbers may.
Aranmar Acoustics use a slightly irregular method of construction as they machine 45 degree recesses from a single piece of wood allowing the sides and top to be 'folded' into place. The front and back panels are then pushed into place and glued.
Due to the construction method that is used for all their loudspeaker cabinets I was able to use just a special tape with quite a bit of elasticity to pull all the joins together whilst the glue set.
Apart from the glue seeping out of the joins (I am a bit over enthusiastic with my glue) you can see the sound-deadening foam material I have used on the walls of the cabinet. It is a vinyl-backed foam which is intended to absorb some of the energy within the cabinet through the addition of mass to the walls.
The driver recesses were cut perfectly so I could push the drivers into place and they would be held there without any screws - really great workmanship.
My lack of woodworking experience was again highlighted when I moved to the finishing stage of the project. I applied five coats of semi-gloss to get as close to a professional finish as possible - I think it may be best to leave this stuff to guys who do it for a living.
Finally the speakers were finished. The Bamboo ply looks really nice after the coating has dried. The Seas Nextel drivers look really great too.