Question about removable front baffles?

[limulus]

I'm not new to diy speakers. I've built about twelve speakers over the last few years. I always build my front baffles 1.5" thick. However, I usually glue them and use biscuits to hold them firm. I notice a lot a beautiful diy speakers with either a black front or a different veneer. I usually use a roundover bit on the vertical edges and then wrap the entire cabinet with veneer and have the seam in the back. I've never been sure how the two piece look is accomplished. Is there a thread somewhere that discusses this?

edit: A good example of the look I'm talking about are the speakers built by Jim Salk...not diy, but he uses multiple veneers on a single speaker.

[Smokinghot]

edit: A good example of the look I'm talking about are the speakers built by Jim Salk...not diy, but he uses multiple veneers on a single speaker.

link and/or pic...?

[cfbuck]

Limulus,

Unattached Baffle

Image not available

Here is a method for attaching baffles ala Jim Salk (salksound.com). They are not however removable as this would spoil the look if screws or bolts were protruding through the front. If bolts were inserted protruding out of the back of the front baffle, and holes drilled into the MDF inner baffle, I suppose that they could be bolted on reaching through the driver hole to the inside and thus removable.

If you look at the 1st photo carefully, you will see a batten, about 3/8" x 1" glued to the MDF inner front baffle, flush with the veneer all around the speaker. It has a 3/8" roundover and mitred corners. The batten is the same stock as the outer front baffle.

The outer baffle 3/8" thick cherry, 2 pieces glued into a panel whose size finishes 1/2" or so, less than the dimensions of the speaker enclosure. This allows the batten roundover to show. The panel has a roundover of 3/8" or in this case a table-edge router bit applied to all sides which gives a more elegant profile than the usual radius. This is glued to a baltic birch ply backing of slightly less than 3/8". The backing is 1/4" smaller than the depression formed by the batten on the MDF. This forms a rebate or lip on the cherry top baffle which rests against the cherry batten, the bb does not quite touch the MDF.

The bb ply is not so apparent from the photo because the driver hole is rounded over from the back for air flow relief to the driver and the BB ply is set back from the edge of the cherry baffle by 7/8". But you can just see a colour difference where the t-nut resides for the driver bolts in the back relief roundover. One could just use 3/4" cherry stock and rabate the back but I feel that the 3/8" cherry is more stable because it is thinner-less stress of wood movement.

The bb ply is then attached to the MDF with great gobs of Liquid Nails or silicone to seal the space between the inner and outer baffles applying enough to make a perfect seal but at the same time not allowing any to squeeze out behind the rebate. I apply what I think is a good quantity, squeeze the baffle on and then remove it, check the coverage and then add some more if required. The Liquid Nails or silicone provides some elasticity for wood movement as it never hardens to the extent of PVA.

Using solid wood against any more stable surface such as bb ply or MDF will eventually make the bond between them fail in climates where there are swings of moisture between summer and winter. Wood absorbs moisture no matter how well it is sealed and continually expands and contracts. Finishing it on all sides is a must to mitigate this action. Also using straight grained, quarter-sawn lumber aids stability. Certain species are also moe prone to movement as well-cherry is more stable and that is why I use it. Jim, however, uses almost any solid wood but often the heavier, exotic speacies and I don't think that he has had any major problems. Hopefully the speaker drivers will be non-functional before this happens-hopefully 50 years or so. I have not had any trouble with movement over 5 years and I live in central Canada-Jim is in Michigan, same climate.

Finished Speaker



The cherry baffle has now matured to a rust shade so that the colour is a good match for the pommele sapele veneer compared to this photo where the cherry is quite pink/light. Cherry darkens substantially with exposure to light.

Hope that this is what you were looking for.

[gimpy]

Sorry, cfbuck. I don't see a pic of the "Unattached Baffle". Just a red "X" in a white square.

[ThomasW]

Shows up fine for me with Firefox and IE6...so you need to check your settings