I am planning on building the Troels Gravesen OBL 15.
Most constructors here seem to favor baltic birch plywood and MDF. While the merits of different plys and MDF have been debated for box speakers is it of equal importance for an open baffle? I am planning on gluing two 3/4" panels together. What material should I use?
Advice appreciated. Thanks.
nash
Most constructors here seem to favor baltic birch plywood and MDF. While the merits of different plys and MDF have been debated for box speakers is it of equal importance for an open baffle? I am planning on gluing two 3/4" panels together. What material should I use?
Advice appreciated. Thanks.
nash
It depends what kind of resonance you mean, a box is a resonant structure, the frequencies set by it's dimensions. As you say all materials have resonance, and their resonance should be minimised in this application. If your OB speaker has any wings or cavity behind the baffle this also will have a resonance
Hi,
Every material has its self-resonance frequency but this becomes an issue if it is excited which is more likely to happen in box speakers because of standing waves. Generally open baffles have to be rigid enough so the driver's cones move relatively to the baffle and not the other way around. I haven't come accross an "audible" baffle but I can confirm that a loosely mounted driver will ring.
Every material has its self-resonance frequency but this becomes an issue if it is excited which is more likely to happen in box speakers because of standing waves. Generally open baffles have to be rigid enough so the driver's cones move relatively to the baffle and not the other way around. I haven't come accross an "audible" baffle but I can confirm that a loosely mounted driver will ring.
Thanks.
Troels says he uses baltic birch ply for all his constructions since it has a very high density and does not have to be veneered. Only problem is that buying baltic birch ply here in the US is difficult so I was considering the stuff available at the big box stores such as birch ply and maple ply which I know is not nearly as good as the baltic birch ply. Thats why I posted the query wondering whether my results will be just as good sonically specifically for OB use.
nash
Troels says he uses baltic birch ply for all his constructions since it has a very high density and does not have to be veneered. Only problem is that buying baltic birch ply here in the US is difficult so I was considering the stuff available at the big box stores such as birch ply and maple ply which I know is not nearly as good as the baltic birch ply. Thats why I posted the query wondering whether my results will be just as good sonically specifically for OB use.
nash
Just yesterday I stumbled upon this thread on OB materials, and some interesting options are mentioned here:
Wood for OB speakers
Hope it helps.
Wood for OB speakers
Hope it helps.
Open baffle speakers have a dipole polar response and it's important to understand how this effects the room and placement
Electro-acoustic models
Instead of opening a separate thread would a live edge slab work for OB? Minimum size would be 20x40 but wouldn't necessarily be perfectly dimensional and would not be a plywood. Large selection of wood slabs, many species to choose from Or would something like this ring or have a tone of itself. If so would laminating a plywood as a backer solve some of this 'tone'?
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Solid wood can be a good speaker building material, but you have to know what you are doing. If it is one big slab, you might need to reinforce it to keep it from warping.
I have speculated about doing OBs with some western red cedar slabs i had on hand (i gave most of them away for others to use), and looked lustfully at some slabs made by a buddy: Urban Milling
dave
I have speculated about doing OBs with some western red cedar slabs i had on hand (i gave most of them away for others to use), and looked lustfully at some slabs made by a buddy: Urban Milling
dave
Thanks folks. I looked at some prices. Some not so bad, some up there. I have some rough sawn Black Walnut. I should probably just take it down to the local cabinet shop, have it finished and glued to get my width. Same wood as this turntable base. And I'm not a woodworker and would be a waste of good money to try and use a slab.
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