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does binding tend to raise or lower the pitch noticibly ? Does the material used effect the outcome ?thanks Jody

Binding is more or less part of the side. It will have little or no influance on the tone as the sides are for the most part an inactive flange that holds the two active diaphrams (top and back)

It turns out that the joint between the top and the side is not quite 'rigid', and it's not quite a 'hinge' either. The liners can flex just a little most of the time, and how much they flex depends on all of the 'usual' factors, like how wide and tall they are, what material, how wide the purfling channel is, the phase of the moon, and so forth.

Generally, routing the binding rabbets causes the top resonant pitches to drop a bit, particularly the 'main top' tap tone. It comes back up a bit when you put the binding on, but the edge is not quite as stiff as it was before you routed it. I always use wood bindings, so I can't say what effect plastic ones would have. I suspect that the more of the liners you take off in routing the rabbets the greater the effect, but can't say for sure.

Alan and Micheal ,Hey thanks for taking the time to respond ... Jody

Recently it occurred to me that perhaps the radius of the binding edge affects tone. Then I tried to retrace the guitars I've seen, it seems to me that the ones with smaller-radius edge sounded more "detailed." Of course I could be wrong ,but it's a good excuse not to spend too much time shaping the edge.

For those of you that believe that the edges of the top don't effect the sound (I used to believe that too!), try an experiment sometime. Build a guitar with no binding and play it. Take the neck off, bind it, and play it again. The sound changes. It's not gonna make or break the guitar but it is worth thinking about.

I can't say whether the binding material makes an audible difference or not because I haven't A/B tested that but I expect that it does, as I expect lining material and size does too. Now I'm not saying that I could listen to two guitars blindfolded and say "that one has plastic binding and that one has flamed western maple." But the edges are definitely something to think about when you get to the point of tweaking the tweaks.

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tweaking the tweaks ???? LOL Jody

Hey Kent , thanks for taking the time to reply , I thought all one had to do was to learn how to tweak the sound, now I discover I will need to tweak the tweaks >> .i guess there is no end to this endless tweakerie ! LOL
thanks for the tip on building the guitar with no binding , that would be an excellent way to see for myself what happens ! I know of at least one builder that does occasionaly build and sell some guitars without bindings . Jody

I heard a big-name builder say that he believes the binding is like the edges of a pool, keeping the "waves" inside. The pool, obviously being the top. Not sure I buy it. Just throwing it out there.

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

The 'waves' pretty well stay within the boundaries of the top, binding or no binding, as far as I can tell. If you think about the lower bout moving in and out like a speaker cone, you'll see that the edge is both very stiff and very massive by comparision with the top itself, so the top can't get very far in pushing it. The measurements I've been able to make suggest that almost all, if not all, of the energy that gets transferred to the back comes through the air in the box, rather than the sides. The main thing that's effected by the binding, as far as acoustics, seems to be the flexibilty of the top edge.

The strange thing though is that I would expect that adding binding would make a looser hinge at the edge. My experience after doing it twice (and getting a second set of ears the second time) is that the tone tightens up. There's more focus and more high partials. Not what I would expect from a looser edge. I still don't have any empirical evidence to explain why but I'm pretty curious, if only because it's so counter-intuitive and counter to conventional wisdom. Fun stuff....

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Kent , possibly that is because when routing for the binding you are making the top plate smaller , ( less area), just a random thought I had ) possibly by several sq.inches , I am not a math wiz , but I think if you route a 1/4" channel, and the entire perimeter of the top is say ( for ease of arguement) 48 " the area of the vibrating top would be reduced by 4 "... also if you glue it well ( i think ) you may not be making the top any " looser" .. Jody

my D 28 is just under 60" at the perimeter... a 1/4" channel would reduce the area of the top by nearly 5" - 5/16 would make it nearly a 6" reduction in total area of the plate

sorry the martin top would be reduced by approximatly 4 " and 5" respectivly Jody

Jody, the last one I did this on, I just added some thin binding that was only as wide as the top is thick. It was meant to test what I think Mike was talking about as the swimming pool effect. I wanted to see if just capping the end grain and not routing into the side or lining would have an effect. It did. At some point I'll go back and put on full size binding and see how that changes it.

I'd buy the change in top size argument if we were talking about going from 1/4" lining to 3/16" lining. But I can't get my head around why replacing a very rigid area of top with binding would make that kind of difference.

But I don't have a better guess either

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I've noticed that the tap tones often go to pot when I rout the binding ledge, and then come back when the binding is on. I attribute that the the fact that the rabbet opens up air leaks all around the edges, changing the pitches and activity of all of the air resonant modes, and their influece on the top. Everything gets back to normal when you put the binding on and seal it back up again. Maybe there are some small leaks around the edges when you glue on the top?

another thought I had is we are most likly stiffening the top some by adding ( at least certain ) bindings .
kent how much did the pitch raise ?subtle but noticable? a half step ? perhaps more ?? Jody

I've strung up a guitar with the ledge cut but no bindings glued and it sounded really poor.

It really seems hard to understand. Yes, they are many small openings in the kerfing, but shouldn't it have (more or less) the same effect as a big soundport?

And stiffness loss, not much at all? A 6mm wide lining secured by a side and the top is pretty stiff in itself...

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Build log

A sound port in the side 'listens to' one or two of the air modes that the normal hole misses, but leaks all the way around catch everything. Since you're draining energy off all of the air modes, and using a pretty high drag setup to do it, it doesn't really surprise me that the guitar sounds dead.

Back when I was working with Carleen Hutchins she built a violin she calls 'La Gruyere'. She punched a bunch of little holes in the ribs, and plugged them up with small corks. If you played it with all the corks in it was a pretty good instrument, but the more corks you pulled out the worse it got. With holes all around the perimeter it sounds like a cheap, tinny fiddle. It shows you how much all of those interior air modes effect the thing, even when you can't hear them directly.