custom-made plywood, other ideas

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casey
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custom-made plywood, other ideas

Post by casey » 2013-11-22 11:10 PM

An email conversation had recently with a friend:

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I have some sitka spruce guitar tops, I wonder what would happen if I made my own plywood out of them, maybe with a thin flexible membrane of some sort in between to add durability, but maintain flexibility to get the air oscillating.

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I'd be very interested to know how homemade plywood turned out. I suppose you'd want non-parallel grain with the plies (a luthier friend of mine suggested that a solid wood top would eventually split without bracing or something to hold it together due to drying/moistening, not to mention being beat on). My instinct is that too flexible a layer in between would damp a lot of the vibrating energy, but that's not necessarily a bad thing: it's kind of hard to know what the "ideal" tapa is, since some people look at it as a wooden drum where the tapa should sing like a drum head, and others (like me) look at it as a "kick drum simulator", where we don't really need that... that said, even a kick-drum guy like me wants his snares to be driven, and vibration helps with that. I have a feeling non-traditional materials could be great there... e.g. i have a clear sheet of plexiglass i'm going to try out some day.

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After reading the feedback from other cajonaires (probably wrong, but I'm gonna run with that word!) on your site, I don't think the flexible homemade ply would produce the sound I'm looking for. I'd also be going for a big kick sound, and I think a pliable-as-possible spruce tapa would sound, well, flacid. It did get me thinking about a design that would isolate the corners from the center of the tapa with diagonal bracing pieces, and potentially use different materials in each area. Have you ever seen anything like that before? Also, did you ever try to put a pickup in it?

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> After reading the feedback from other cajonaires (probably wrong, but I'm gonna run with that word!) on your site, I don't think the flexible homemade ply would produce the sound I'm looking for. I'd also be going for a big kick sound, and I think a pliable-as-possible spruce tapa would sound, well, flacid.

Frankly I'm not sure the tapa really even matters that much for the kick sound... well, depending on what one means by "kick". When i play mine, at least, the kick seems to be more about the general thud of the wavefront and not the vibration of the wood. My hand hits the tapa and stays there -- deadening it almost completely. I think as long as the tapa can move a bit (i.e. 1/2" plywood obviously wouldn't work so well) it'll work out... I think it just depends on the box at that point: dimensions, size of hole, rigidity, and how well it's sealed. Maybe a floppy tapa decreases the box's overall rigidity to the point where it matters, though. Dunno.

> It did get me thinking about a design that would isolate the corners from the center of the tapa with diagonal bracing pieces, and potentially use different materials in each area. Have you ever seen anything like that before?

I've definitely seen pictures of cajons with multiple chambers; similar to what you're describing. Seems interesting. I'd be concerned with how a tiny little corner braced all unto itself would actually sound; like, at that size, it's hard to imagine there being any resonance or vibration really happening in the wood (at audible frequencies), but i bet you could work something out. I think for the trouble it might be easier to just make two different drums. :-)

> Also, did you ever try to put a pickup in it?

Indeed. That's a whole 'nother section of the site i haven't had time to create yet. I put two in. Neither sound phenomenal. Both are piezo disc. One is a relatively fancy guitar pickup, the other is a generic element from an electronic supply place... I was going for a "kick" and a "snare" pickup. When I record with it, I generally end up throwing the pickup tracks out, though I sometimes use the low end of one of them in the kick mix (the "snare" pickup, ironically). I'm sure there's a way to make it work with the right element, right placement, right mixing... haven't found it yet. One of the pickups going through a tube amp into a bass cabinet does sound pretty good, though. But if I was playing live with it I'd want to know that the sound guy was good. :-)

s.pathak
Posts: 2
Joined: 2015-04-28 9:15 AM

Re: custom-made plywood, other ideas

Post by s.pathak » 2015-04-29 5:26 PM

casey wrote:An email conversation had recently with a friend:

-----------

I have some sitka spruce guitar tops, I wonder what would happen if I made my own plywoodout of them, maybe with a thin flexible membrane of some sort in between to add durability, but maintain flexibility to get the air oscillating.

-------------

I'd be very interested to know how homemade plywood turned out. I suppose you'd want non-parallel grain with the plies (a luthier friend of mine suggested that a solid wood top would eventually split without bracing or something to hold it together due to drying/moistening, not to mention being beat on). My instinct is that too flexible a layer in between would damp a lot of the vibrating energy, but that's not necessarily a bad thing: it's kind of hard to know what the "ideal" tapa is, since some people look at it as a wooden drum where the tapa should sing like a drum head, and others (like me) look at it as a "kick drum simulator", where we don't really need that... that said, even a kick-drum guy like me wants his snares to be driven, and vibration helps with that. I have a feeling non-traditional materials could be great there... e.g. i have a clear sheet of plexiglass i'm going to try out some day.

------------

After reading the feedback from other cajonaires (probably wrong, but I'm gonna run with that word!) on your site, I don't think the flexible homemade ply would produce the sound I'm looking for. I'd also be going for a big kick sound, and I think a pliable-as-possible spruce tapa would sound, well, flacid. It did get me thinking about a design that would isolate the corners from the center of the tapa with diagonal bracing pieces, and potentially use different materials in each area. Have you ever seen anything like that before? Also, did you ever try to put a pickup in it?

-------------

> After reading the feedback from other cajonaires (probably wrong, but I'm gonna run with that word!) on your site, I don't think the flexible homemade ply would produce the sound I'm looking for. I'd also be going for a big kick sound, and I think a pliable-as-possible spruce tapa would sound, well, flacid.

Frankly I'm not sure the tapa really even matters that much for the kick sound... well, depending on what one means by "kick". When i play mine, at least, the kick seems to be more about the general thud of the wavefront and not the vibration of the wood. My hand hits the tapa and stays there -- deadening it almost completely. I think as long as the tapa can move a bit (i.e. 1/2" plywood obviously wouldn't work so well) it'll work out... I think it just depends on the box at that point: dimensions, size of hole, rigidity, and how well it's sealed. Maybe a floppy tapa decreases the box's overall rigidity to the point where it matters, though. Dunno.

> It did get me thinking about a design that would isolate the corners from the center of the tapa with diagonal bracing pieces, and potentially use different materials in each area. Have you ever seen anything like that before?

I've definitely seen pictures of cajons with multiple chambers; similar to what you're describing. Seems interesting. I'd be concerned with how a tiny little corner braced all unto itself would actually sound; like, at that size, it's hard to imagine there being any resonance or vibration really happening in the wood (at audible frequencies), but i bet you could work something out. I think for the trouble it might be easier to just make two different drums. :-)

> Also, did you ever try to put a pickup in it?

Indeed. That's a whole 'nother section of the site i haven't had time to create yet. I put two in. Neither sound phenomenal. Both are piezo disc. One is a relatively fancy guitar pickup, the other is a generic element from an electronic supply place... I was going for a "kick" and a "snare" pickup. When I record with it, I generally end up throwing the pickup tracks out, though I sometimes use the low end of one of them in the kick mix (the "snare" pickup, ironically). I'm sure there's a way to make it work with the right element, right placement, right mixing... haven't found it yet. One of the pickups going through a tube amp into a bass cabinet does sound pretty good, though. But if I was playing live with it I'd want to know that the sound guy was good. :-)

Sitka is by far the most common type of wood used for solid spruce tops. If it were alpine or Adirondack spruce they would probably make a point of saying so.

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