I'm building a set of 5 speaker cabinets for a home theater and i'd
like some construction advice, and some advice on what type of finish
The speakers are about 2.5' ft tall by 10" wide by 1' deep. Cabinet
material is (not surprisingly) 3/4" MDF.
In the past, I've used butt joints. While this method worked fine,
this time around I plan on doing all the joints as 3/4 dovetail; i
chose this method because i wanted the maximum amount of surface area
for gluing, and I figure as the MDF ages, this will provide the most
stability with regard to expansion/contraction. I'll also countersink
the drivers into the baffle with rabbets; I plan on using a
circle-cutting jig attached to my plunge router to cut the rabbets and
holes. Are there any other construction tips folks can offer
regarding speaker cabinet construction?
now, With regard to the finish. I have had problems in the past
getting an even finish on the MDF endgrain, and with the dovetail
joinery, i will have an odd endgrain pattern. To combat this on the
baffle, I was going to rout out 3/4"x1/8" around the outer edge of the
baffle and inlay some cherry in that channel. However, I don't want
to rout the endges of the whole cabinet on every surface. How does
one finish MDF to get a uniform look? I wanted to do a piano black
gloss finish for the whle cabinet, but after reading some posts this
seems impractical unless I send it someplace. Any idea where I could
take the cabinets/what this would cost for 5 speakers (i am in boston,
MA)? What alternative finishes are there that are more easily
thanks for your thoughts.
A different choice to dovetails would be a simple butt joint and add
1/2 or 3/4 quarter round to the inside corners. This would save a lot
of work and be just as stable. The quarter round would not affect the
volume calculations too much.
On 5 Jan 2004 07:26:20 -0800, email@example.com (Rich Wilner)
Strictly in the FWIW department: In the past I've provided a few mdf cabs
for a high end speaker manufacturer when their main supplier, a local
cabinet shop with cnc equipment, was swamped. They provided me with the
material, dimensions, and specified glued rabbet joints for the box
construction. These speakers start around $5K for the pair, so they must
feel this a good, perhaps best, method for speaker box joinery.
you beat me to the punch re: high end speakers aren't dovetailed. I
used to be a dedicated audiophile who can't recall seeing any expensive
speaker cabinets with such joinery. Not that they don't exist, but it
isn't the norm.
I've never seen touring stuff dovetailed either. All glued rabbets
and dados, with extra internal bracing at high-stress joints.
I have seen the occasional box or finger joint in studios, but usually
in furniture quality racks, not speakers.
The most important part for speaker cabinets is to be air-tight,
a function easier to acheive with rabbet joints than dove-tails,
especially with MDF (atleast for those of us who arent Frank
Blind dove tails might be okay, but then you mentioned exposed
endgrain, so I suppose you were planning on through dove-tails.
I would second the recommendation on rabets.
I'd suggest you try a sample MDF dovetail joint beforehand. You'll probably
find that the glue will swell the MDF joint to the point where you won't be
able to assemble the joint, even if you work rapidly. Simple dado's are
probably your best bet with MDF
If you are interested there is a new material that is used on piano's that
will give you that great glossy black. The material is a sheet material
milar to a digh density laminate (it probably is, but I'm not sure) that
would eliminate your whole problem with the edges of the MDF.
Charles A. Peavey
thanks for your replies everyone. I think I will go with rabbet
joints as it is a ton less work, and that seems to be the consensus of
those that know more than I.
charles: can you tell me more about this finish? where can I obtain
it? how is it applied (like any other veneer)? how durable is it?
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