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How To Make Body Chambers?


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All those things probably do make a difference, as does the thickness of the top, the depth of the body, and how the bridge puts sting load into the body. The thicker you make the top and the more direct the connection between the bridge, thru the body to the neck, the less influence the chambers will have.

If you look at the Warmoth site, Tele bodies can be had routed out as a Thinline or just lightened. The Thinline has two big chambers on either side of the central slab and a little pocket at the tail. The hollowed option has a bunch of little cavities, presumably to make them less acoustically active.

So, size and shape make a difference. Putting in vents makes the body a ported resonating chamber. Oh yeah, and then there's the wood. To see how all this stuff interacts, you need to experiment and see. Is there a chambered guitar whose tone you want to emulate? Try to see how they did it and use that as a starting point.

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Hey Matt,

Yes, the chambers matter. But in what way? Who knows. It has so much to do with the materials and the direction of sound propagation, yada yada yada.

Some people will tell that their chambering will emphasize certain frequencies. They are blowing smoke up your @ss. Ask them what frequencies. Ask them to prove it. Then watch them run away from you.

Guitar Ed

My $.02 in a $.03 world.

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My next Bocaster's going to be a thinline...actually, I'm looking at getting as close to a hollow body as I can. Why? Just because... ;-D

Looking at the warmoth thinline ---tele_thinline_side.jpg

I'm thinking I can add 'tunnels' through the center core that will allow air to pass through all of the chambers without compromising the strength of the core.

Is this feasible?

I'll be routing from the back of the guitar and covering that with panels stolen from an old acoustic...I might consider routing the front though and picking up some bookmatched maple (there's a guy in Germany, sells panels pretty cheaply), since I'll want a natural finish and the glue lines from the bocaster conversion will show through otherwise. There's also the option of routing front and back to make just a frame out of it, and adding panels to both sides...but then I think I'd lose too much of the alder's sound.

As for the air vents --in addition to letting the sound out of the chambers, they also add a really nice design element. I can't believe the shape matters-- I think the f-hole is just a matter of tradition, a stradivarious thing....for the bocaster, I'll be doing thin rectangular holes!

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ok well im making a mahogany body with maple top, and i want to lighten it. then ther will be two smallish vents (like the ones on the BMW Z3) on each side about where the waist of the guitar is, simply to look good.

What would this do?

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Hey Matt,

Yes, the chambers matter. But in what way? Who knows. It has so much to do with the materials and the direction of sound propagation, yada yada yada.

Some people will tell that their chambering will emphasize certain frequencies. They are blowing smoke up your @ss. Ask them what frequencies. Ask them to prove it. Then watch them run away from you.

Matt speaks the gospel. Listen to him. Print out his post, and read it every morning.

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I swear, you can tell how far along the path a guy has gotten building guitars when he starts talking -seriously- about the sonic properties of sound chambers. Usually around the second or third guitar, hehehe. :DB)

Some people come completely unwound talking about that hoo-doo voodoo.

The more serious they are, the more I get to laugh. I have read posts that literally are more than a complete page long with authenticated scientific drivel ad nauseum about that kind of thing.

It IS fun to read, tho I don't take any of it seriously. :D

I've put all kinds of cool voodoo chambers and round burial chambers with secret tone transmission holes to the dead souls and stuff like that in guitars, but I'll be damned if I can explain the tonal difference, I just like 'em, and leave it at that.

It's so simple that way. :D

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I like the way this thread is going so far. B) "Keepin' it real"

About the only thing of value I can add that a newbie might not consider is that it will make a very big difference if you're "chambers" actually change the way the bridge vibrates. So what I mean is, if your top is "floating" and there's no wood under the bridge, that will be a whole different deal. It will soften the sustain, and depending on how thin the top is, it could add some acoustic-like snap to the attack, the same type of attack a jazzbox has. If the chambers cut into the bridge area so much that the bridge and studs aren't really driving the body at all, then you've sort of detatched the "tone generator" and perhaps even minimized the effect of the chambers.

I hope that puts me in the "keepin it real" category and not the "long dissertation about a load of crap" category. :D

As for the Z3 vents and what will they do? They'll leave a place for the cockroaches to get in and out.

No seriously, the decision to open or close a sound chamber will have an effect on the acoustical properties of the chamber. You might hear the difference playing the guitar unplugged, but it's doubtful that would translate to any change in the electric sound coming out the output jack. I think it's a cool idea because I think it will look cool!

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About the only thing of value I can add that a newbie might not consider is that it will make a very big difference if you're "chambers" actually change the way the bridge vibrates.

Okay, that makes sense...

This reminds me of another discussion a few weeks back --I'd posted a blurb from some geek discussing the sonic properties of body SHAPE...a lot of people took that seriously.

And I definitely like the idea of adding sound vents in the sides...just because no one ever does it that way...I've been thinking about picking up a set of small resonator grills as a flashy cover for the holes...

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And I definitely like the idea of adding sound vents in the sides...just because no one ever does it that way...

No, it's been done. It shows up more on archtop guitars. It's sort of like a monitor, directing sound to the player to hear what they're doing.

a Harrison

a Buscarino

Linda Manzer put in a sliding door on the side port.

Someone also does a hinged door that forms a speaker horn that projects sound right at your head.

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And I definitely like the idea of adding sound vents in the sides...just because no one ever does it that way...

No, it's been done. It shows up more on archtop guitars. It's sort of like a monitor, directing sound to the player to hear what they're doing.

Excellent! Thanks for the links...you sure know your way around all the funky guitars!

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I've put all kinds of cool voodoo chambers and round burial chambers with secret tone transmission holes to the dead souls and stuff like that in guitars, but I'll be damned if I can explain the tonal difference, I just like 'em, and leave it at that.

I'm with you on this one Drak. I have tried several variations and now I just make them look cool. They sound better that way! :D

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Remember, the guitar produces a very finite amount of energy. I don't know that a guitar can drive a long intestinal port without suffering some sustain loss or some combing/phase cancellation. So the sound tunnel might be a good theory, but in a Bose system, the drivers have "unlimited" power assisted energy. I mean it's limited by the amp's power and the drivers' physical limits, but what I mean is, the "tube" takes a certain amount of base energy to drive. With the Bose radio, you just turn it up until you get the desired volume. But the guitar might not have enough power to benefit from it. An idea like that may be better suited for an acoustic guitar amp.

Someday I'm going to build a guitar I designed that has a Bugle shaped hole in it that runs from the bass side waist to the treble side cutaway, passing hidden between the two humbuckers. (wouldn't work with a middle pickup) This way the guitar top would be about as thin as an acoustic between the humbuckers. Do you ever hear that cool snappy sound you get from a Strat that has the bathtub route under the pickguard? I'm thinking I might get that, mixed with a little Ibanez Maxxas type sound. I think I want to make a secondary chamber under the bridge, though, to do what I described in my last post. I want to make the bridge vibrate and sustain like an archtop does by thinning out the surface under the bridge. So far most hollow chambers run "nut-to-bridge" and they leave the steinberger meat under the pickups and bridge. I'd like to start experimenting with removing that wood instead. Heck even a 335 has a center block.

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There's an analogy that's used for fluid flow and dynamics, "it's easier to drink soda through a straw than a garden hose." It's easier to propagate a pressure wave through a narrow column than a much wider cavity. The acoustic energy is directed along the length of the column.

In a large cavity, the pressure wave travels out in all directions, from the source. More of the energy is being dissipated by moving air in directions that aren't toward the intended receiver. That's the reason that horns (bugles, trumpets, trombones, etc) are shaped the way they are. Back in the early days of recording, before amplification, special instruments were built that were loud enough to recorded. Guitars, violins, ukuleles had bridges mounted on little diaphragms that drove big Victorola shaped horns, that were pointed at the acoustic microphone and it's stylus cut the record.

I'm just talking about a chambered solid body, where the bridge isn't directly driving the entire top, like it would with an acoustic. For the folded horn to work, the bridge would have to be driving a small surface that would radiate into the column.

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  • 1 month later...

"some geek" - pretty harsh words from someone who likes rectangular shaped guitars, doncha think? LOL

The biggest problem with quantifying any of this stuff is you cannot test it nor can you prove it. Every piece of wood is different. I personally like chambers, I think they do add resonance and lighten the body. What more do you really need?

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