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I've been doing final voicing on the top by thinning the edges after closing the box but before routing the binding channels. I go for a nice throaty open resonance with tapping around the lower bout. For some reason even after 32 guitars I've never checked it after routing the channels but before binding.
Did that today and Wow! After routing for binding and herringbone purfling it went from sounding like a million bucks to sounding like a cigar box. Pretty amazing. Put on the binding and it's better again. I didn't expect such a dramatic difference.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Yes, and it is funny after you glue half of the binding. It pretty much sounds like 500k now... The effect binding has is amazing, like sort of a vibration wall?
It can't be all stiffness, can it? The side+linings is 8mm, take away 2 you are left with 6 which is still sufficient glue up area.
Al?

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Build log

Even with binding channels that didn't expose any little hole, the taptone changed a lot after routing.

I've had the same experience

Oh yes definitely. And for what it's worth one of the reasons I always use wood bindings.

Yep you will hear a big difference between an unbound and routed for bindings box and a bound box.

I always use wood bindings too but I am not willing to assert that wood bindings sound different/better/worse/etc.

Ask Al about the hinge effect.

I think routing the channels loosens tops and backs by reducing the contact area between the plates and the sides, leaving the perimeter of the plate more free to vibrate. The effect is greater on the top after doing the purfling channels. The binding and purfling put back the lost area. Looking at these changes using Chladni patterns seems to indicate that the resonant frequency drops after routing, and comes back up with the binding and purfling on, but not quite all the way back.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Are there any comparisons of this effect between solid or kerfed linings ? If the theory of reducing the contact area between the plates and the sides holds up, solid linings could minimally reduce this effect ?

The dead sounding top after the binding ledges have been cut and the binding isn't in place
yet is something that the builder should never show the future owner of a guitar. I had a customer
who happened to be in the area when I told him that I'd just cut the ledges to install his binding and
was bending his binding while we spoke. Now, this guy lives in Philly and makes it to my shop on
occasion to watch his guitars come together.

He had been there the day I voiced the top bracing on this same guitar and he was really excited
to actually experience and observe the process...not to mention hear the effects of the voicing
process on the top as I tpped it for him to listen to throughout the whole thing.

He arrived as I was bending the binding and he got to hold and look at his body with the ledges cut
for it. He tapped the top and got this confused look on his face and asked if I had subsituted his
beautifully resonant responsive top for this dead muted piece of cardboard that made the body sound
like there was a rag stuffed in the soundhole.

I had to explain that it was a common occurrence and that every top went "dead" at this point in the
construction process. I even showed him my signature and his initials inside the top that we had put
there together on the day that it was voiced.

Once the binding was done and it was sounding loud and impressive again, he made a special trip
just to hear it and to check out the binding. He was a happy camper again and glad that he'd chosen
that great sounding top.

It's an interesting thing that many builders have different explanations for.

Regards,
Kevin Gallagher/Omega Guitars

I've bound guitars with wood and ivoroid/tortoise and have heard no difference. Herringbone had always interested me as you take a little more top than with a simple bwb changing the contact forces with the lining. I can't honestly say I've heard a difference there either though. I would guess that when routing the channels you open up a bunch of mini soundports that dissipate the air pressure in the box.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I think routing the channels loosens tops and backs by reducing the contact area between the plates and the sides, leaving the perimeter of the plate more free to vibrate. The effect is greater on the top after doing the purfling channels. The binding and purfling put back the lost area. Looking at these changes using Chladni patterns seems to indicate that the resonant frequency drops after routing, and comes back up with the binding and purfling on, but not quite all the way back.

Pat

Pat is alsolutely right!
Re-read what he says and you'll get a handle on the situation!
He said it so right !!

Mike

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Mike Collins

What Mike said. When you rout around the edges they become a little more 'hinge-like' and less rigid. That's what accounts for the change in tap tone frequency. The binding ads some of that stiffness back, but not all of it.

I think a lot of the added damping comes from the air leaks as you cut into the liner kerfs. One of these days I've got to put some masking tape on the ledge to seal the holes and see if that's the case.

I have been using solid linings and I have not noticed a large difference in the tone when the binding and purfling are routed but not installed. I also haven't really been looking but I don't remember it being that different. I will definitely check next time.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

I miss read this and thought Pat had my new most favorite signature. Maybe I'll adopt it as my own.

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Mike Lindstrom

I am stunned. Here i read that every effort is taken to develop the tone and now you all are admitting that you purposefully destroy and the rebuild the tone, somewhat unsuccessfully, for the sake of appearance? Am i wrong to thinking that another way should be found to eliminate the need to cut all the way through the top and sides? We have those plastic corner moldings that protect the corners of walls, wouldn't it make sense to do something similar here? Or why does the wood need to be routed all the way to the kerfing? Can't it be as shallow as the rosette? Is there all that much benefit from purfling and binding?

Of course i am half joking here, but half serious too. These threads are full of discussions as to whether shellacing the inside affects tone or not, or if one finish is better for tone than another, or does this wood make it more bright than another, and does bone vs. plastic vs. fossilised walrus penises give the ultimate tone... and yet no one batts an eye over this?

So the question is: does binding /purfling give a real benefit to the overall guitar, or is it cosmetics?

Yes, on both counts!

Yes! So the resonant frequency seems to drop and come mostly back up after the bindings are glued on. I don't see how that destroys tone. If you're building to a particular frequency, you compensate. Some would say finish destroys tone too, same with no finish.

Binding does perform a function in keeping the end grain from losing moisture too much more quickly than the rest of the plates, especially important for the top, and provides protection for the edges, especially soft top wood. And sometimes it can be so dang pretty.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

I made thicker sides, thinner binding, and shallower top pufling, to find out that it's not the case. The added damping comes from the structure change IMO.

On the other hand, I remembered a grand master said that the soundboard has to in be "dead." Perhaps it's a good time for a guitar to be strung in that regard! Just kidding...

I prefer to have my bindings lower and not to wide. They're relatively easier to be glued properly because being more pliable.

Pat, i was just pointing out that a couple of posts said that the tone doesn't always come back to pre-binding levels.



Need a smiley for "the thinker".... I am not sure i am buying that line Pat. The top should be dry already, specially if you are in the shake and bake camp. Perhaps it thelps to protect the ends agains repeated swelling and drying, but again, couldn't a shallow binding do that, or even proper finishing?


That one i'll agree with to some degree, but - and the repairmen can justify it - how often is there damage to an edge? Does the binding need to go all the way through to the kerfing to provide "enough" protection? What if the routing was shallow and the binding left raised? Obviously the binding would then need to be finished off in some manner. I do remember seeing an archtop, where a bead was left around the edge. It looked pretty cool. Seeing as the sides are normally some tougher species, what if the top were set some and the side was left raised as a bead around the edge? Would that provide adequate protection? I'm kinda liking that thought.

Maybe my building or my ears/fingers (or both) are different from everyone else but when the bindings/purflings are on and the glue fully dried/hardened, the responsiveness, sound and "feel" of the top and box is much better than when the box was fully closed before the binding channels were routed. To me the bindings form a tonal, protective and visual aesthetic purpose.

Mind you if you want the best responsive state of the top, just skip the step where you put sides and a back on it.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Rob,

You wrote, "i was just pointing out that a couple of posts said that the tone doesn't always come back to pre-binding levels."

Tone and resonant frequency are not the same thing. The resonant frequency comes back almost to the pre-routing level, in my limited experience. No one has said the tone doesn't come back. A slight drop in resonant frequency does not mean the tone is destroyed. It may, in fact, have no discernible effect at all.

"I am not sure i am buying that line Pat. The top should be dry already, specially if you are in the shake and bake camp. Perhaps it thelps to protect the ends agains repeated swelling and drying, but again, couldn't a shallow binding do that, or even proper finishing?"

The issue for the top is not simply whether the top dries out or not. I wrote, "keeping the end grain from losing moisture too much more quickly than the rest of the plates". Of course, "the top should be dry already" as you said, but the real issue here is that the endgrain parts of the plate lose moisture much more readily than the rest of it, particularly important with spruce and other common softer top woods. The finish on a guitar is not much of a barrier to moisture.

If routing the channels for binding and purfling ruined tone, there wouldn't be thousands of guitars out there with channels routed into the linings.

If you build some guitars that disprove these (arguably) widely held beliefs, I'd like to hear about them.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Thanks for the distinction. Looking back over the posts though, in my own ignorant defense, there's a lot of mixing of terminology. Some mention tone (either directly or as Tap tone) and some talk about the resonant frequency, and some... ...i can't decipher. Is that tone or frequency?

pineknot,


The difference in effect between solid and "standard" linings would be hard to determine, since the added stiffness in the solid linings would introduce an extra variable (not that we have control of any variables when making guitars). So, we wouldn't know if it was the stiffness or lack of holes from the kerfs.

Rob,



Probably both. If the top and back frequencies fall too far, they'll sound dead, flat and/or muddy and give you a cigar box tone. Also, the presence of a bunch of little holes from the exposed kerfs would have some effect on the air space inside the body I would think, perhaps acting like a sort of baffle. They all affect each other, though it appears that the top and back don't directly interact so much. And I would venture to say that the tone doesn't affect resonant frequencies but rather resonant frequencies affect tone, but that could easily become a chicken-or-the-egg discussion.
That's my story, and I'm sticking to it, unless I'm wrong.

Read all you can find on the web by Alan Carruth, and there's a lot. If you're like me, after a few years, you might start to think some of it makes sense ( but don't be too sure).

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Seems like a really good test would be to finish the guitar (in the white) with no bindings, string it up and play it. Record the results with a decent reproducible recording setup. Now add the bindings and see what the difference is using memory and a comparison of the recordings.

At the end of the day, we don't care what the tap tone sounds like but rather what the strung up guitar sounds like.

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