School me on chambering

[cstar]

You guys offered a wealth of knowledge in response to my last inquiry.

This one is about chambering.

So: I suppose that the idea behind chambering is to increase the resonance. More pockets inside the body = more sustain, clarity, etc? But does the shape and size of the chambers matter? And if so, how so? I have looked at the images Warmoth provides of their chambered strat bodies, and it seems to me that they methodically remove as much material as possible without turning the body into a semi hollow body, which would have one giant cavity (almost like an acoustic I suppose).

But, would a bunch of tiny circular/cylindrical pockets work just as well? How critical is the shape, size, etc?

Sorry if this is a weird / stupid question.

[Praxist]

for me it's about removing weight. I never even considered the tone being predictably effected before. If the chambers did not vent to the outside, how woudl they impact the tone? Of course I've read all kinds of statemetns here and there on chambers and the amazing tone they provide, but I've always thought of that as marketing bs (for example minarik). I haven't a real clue, but I'm always wary of the tonewood debacle as it's regularly battled about in this forum!

[cstar]

Oh haha well to be fair I never thought about it as a means of removing weight! But then again I do play a ~14 lb jazz...

Hmmm, I couldn't being to explain to you why or why not it might make a difference tone wise, it's just what I had heard. That is helped it resonate better or something to that effect.

[tjclem]

The times I have done it the basses seem to be louder than if they weren't chambered. I know I can't justify/quantify that in any way but that has been my gut feeling from doing it. Not sure if any others have noticed this?

[cstar]

Yeah, that's what I've seen others say. Thanks for sharing.

[cstar]

I read somewhere that Sadowsky started chambering his bodies to reduce weight when he couldn't get light enough blanks and that his customers actually told him that they noticed a tonal difference.

[francotedescoga]

IME, chambers do not affect the tone when the bass is pluged in, at least not in a noticeable level for me. On the other hand, when playing unplugged, it gets loud! I really don't know if the shape, size of position of the chambers is a relevant factor.

[Nidan]

I've built several chambered instruments , in addition to the weight reduction , I've found they have a somewhat fuller sound then similar instruments I've built without .

[bassteban]

I am no luthier, but have had a few basses built- IME chambering adds acoustic volume & some *color*(more non-fundamental content)but seems to do nothing for sustain & may in fact detract. Clarity also seems lessened in the very low registers(D & below on a BEADGC's B string)- this was also Chris Stambaugh's opinion. Generally, upper-reg sounds a tad bit more *guitaresque* while lows get slightly muddy, more so the deeper/lower they go.

[jordan_frerichs]

Since chambering is mostly done on instruments with similar hardware as regular solid body instruments, most of the sound effect that comes from chambering takes a back seat to these variables. Its not difficult to do, just make sure to have a 3/4"-1" border on the edges. Its a lot like a solid body, just router out the cavities and add a top and/or back depending on with side you route from, and if you fully plow through the core wood. Aim for a minimum top/back thickness of 1/4". Also, make sure you think over where you put the cavities, so it doesn't detract fromthe centerlone integrity of the body. Pretty much, stay away from the zone that the strings lay over for the chambers. Also, make sure to consider your body contours when plotting out the cavities, so you don't make accidental holes into the interior cavities. I've done this a time or two, but made it work in the end. Some say that you can sometimes get an undesirable feedback if you make the cavity sizes too large. You get prevent this by making several unconnected cavities. Some people line there's with copper shielding or styrafoam to help prevent this. Im still working on completing my hollowbody and chambered projects, so I can't really comment on final sounds frompersonal experience. This is just the basic sum of my research.

[reverendrally]

Disclaimer; I'm not an expert and have no scientific proof beyond anecdotal experience. So far I've built 3 basses. 2 are chambered. My 4th bass has a HUGE cavity routed out of the middle of the body so I don't know how it fits in exactly.

Like others have said it comes down to a few things.
1. Weight; just remember though, you need to remove huge amounts of wood to have a real effect here. My first chambered bass is heavily chambered but still weighs 9pnds (aprox).
2. Tone; there are two things going on here really.
A. less timber holding the tension of the strings thereby allowing a little more flex in the body. The function of all bodies is flex/lack to change the sound in some way. As you probably know neck joint also effects this. Well chambering does as well. It effectively lowers the density of the whole body.
B. Actual resonance in the body chambers. To do this you need to think also about the thickness of the top as well as the size of the chamber. If the top is still 5mm thick and not actually supporting the strings, the ability for it to resonate is gonna be severely restricted. Thinning the top round the edges of the chamber will make a difference here I've found, but then you risk it being fragile. To give you an idea of the sound of the chamber here's a soundclip I recorded with an Ehrlund linear (contact) mic...
http://soundcloud.com/simpleinnovati...ehrlund-pickup
Now the same bass with a piezo...
http://soundcloud.com/simpleinnovati...orn-with-piezo
And finally with a combo piezo and mag pickup...
http://soundcloud.com/simpleinnovati...ass-guitar-all

Bass in question

Internal chambering (before gluing)

And if I was to do it again, I'd rout out even more wood...

I'll just make a comment about sound-holes too. Both my chambered basses have soundholes. I found without them, it choked up any acoustic sound the bass had. I don't think it greatly matters the size of the port/hole, but if you wanna hear it, you gotta let it breath.