Official Luthiers Forum!

OK, I KNOW this is a subject covered endlessly here. But when one buys a kit from Martin, Bluescreek, etc, this is one area that no amount of RTFM will do!! So, what does a novice builder do? Argh! Do I just wait till the body is assembled and then get my dremel out?

Mike

Get the Mayes Videos & just go for it!

Link please

No.


[In the style of the Grumpster]

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I wrote a series of articles on 'free' plate tuning using the Chladni ('glitter pattern') method some years ago for 'American Lutherie'. They're out in one of the 'Big Red Books' that you can get from the GAL. In fact, there have been several articles on 'tap tuning' in that mag.

David Hurd put out a book a few years ago called 'Left Brain Lutherie', where he details his methods of deflection testing. It's a tad on the technical side, but good and useful infoprmation nonetheless, IMO.

Mike Collins was here Friday, and shot six hours worth of tape for a plate tuning DVD. I don't envy his editor, but when that's done it might be helpful. Somehow this stuff always makes more sense visually than it does in print.

OK practical help.....

until you've made a few, don't even try for the holy grail of resonance at a single pitch.

I'm a sceptic anyway beacuse tuning a top to a single note is (IMHO) a waste of time as once you stick a bridge on there, the pitch is going to change, right?

so, to quote Sam Irwin from Lowden & Avalon, who taught the instrumant class I attended, when you're carving your braces, hold the top ballanced on your finger through the soundhole. tap where the bridge will be. you're looking for a "musicality" (Sam's word) in the wood. if it thuds, take more off. if it rings like a bell, you're getting there.

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I agree with my pal Martin the dumpster diver........

Shoot for an "abundance of ring" as opposed to the d*eaded "thud"..........

If it thuds near a brace remove material from the side of the brace until you have a triangular cross section first. If it still thuds remove height from the brace and reprofile to the triangular shape cross section and tap it again and see where you are.

My tuning starts with only the X-brace installed and using the above process. Then I add tone bars and repeat the above process, finally the finger braces and again I repeat the process. Be wary of where the fingers and tone bars intersect the X-brace as these are problematic areas where over bracing is happening. Using a chisel reduce the height of the tone bars and fingers where they butt the X until the ringing returns. All along the way try to get a feel for flexing the entire top in your hands. Although it will not mean any thing to you now in time and with experience you will gain an understanding of what level of flex you want in a top that is braced.

Typically I add the bridge plate last, it is butted to the X-braces and not inlet, and I find that adding the plate usually enhances the ring of the top and I am usually done.

Again, for now, forget about the note - just get the sucker ringing well in every location below the center of the sound hole. I also hold the top in a variety of places that help to not dampen the plates ability to ring. One of the places is to hold it 1/4 of it's physical height down from the top on either the very right or left side - this is usually just below the end of the upper transverse brace. You can balance it on the sound hole like my pal Martin indicated or with the center of the upper transverse brace. Where you hold it is very important to how well it will ring.

Another tweak you can make is thinning the edges of the top (lower bout) after the box is glued up but before it is bound. If the middle is say .110 I've been winding up around 0.085-.090 at the edges. I'm pretty convinced the tap tone of the top opens up a little after doing it and that it has helped the sound of the finished product.
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.

Thanks Hesh & Martin! Good, practical stuff. I never thought about tuning as you add the braces (instead of after they are all glued down). Good thing I waited.

Terrance, I have read about that concept somewhere. It appeals to my mechanical brain.

Howard, not sure how your response is to be taken.

Mike

A lot of what I learned about tuning a top came from Lance.

Terry my friend I agree with you and learned from Lance that you thin the outer perimeter of the top until you can feel a slight bit of softness in the bridge area with moderate pressure and your thumb. I think that it helps to let the top move/pump more freely and opens up the guitar's tone and response too.

Laurent mentioned the other day that he set out to develop his "feel" for tuning and I did this too from the get-go. As subjective as sticking your thumb on the bridge area and pressing moderately may sound to some after a while you will develop a feel and expectations. To me I was aware all along that the the old masters had to have this feel and did not have the benefit of dial indicators, deflection testing, glitter patterns, and strobe tuners with clip on transducers........

Feel your wood every opportunity that you get.

I like to glue all of my braces in and then tap as I thin them out. Then I try to thin until I lose the fundamental tone and I have a lot of different tones as I tap holding the top in different places. I guess you could call that a musical stopping point. I almost go until it is a little flabby sounding because you're going to get some stiffness back when it's glued to the sides and you get that bridge on. Remember that it is still a guessing game until you put on the biggest brace, the bridge.

Some will glue the top onto the sides first before they get serious about tapping and shaving.

I've found that different species need slightly different approaches. Unfortunately there is no shortcut for your own experience and you know what you want it to sound like in the end. Just find a guitar that you like and try to take measurements of the brace size and location and start from there. You won't know the top stiffness but you might get lucky.

I like thinning the edge of the top too. That happens for me when I sand the bindings, to some extent anyway.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

The pitch of the various tap tones seems to be much less important than how clearly they sound out. This corresponds quite well with the shapes of the 'glitter patterns'. As Mark Blanchard said in his talk at last summer's H'burg fest: "Chladni patterns are to tap tones as written language is to spoken". I find it much easier to remember stuff and communicate it accurately to others when I can write it down, and this can speed up progress.

I'd be willing to bet that, in the end, we're all doing pretty much the same things by different means. It would be fun (and a LOT of work) to get all of the different methods together and compare them.

I do 3 things that I learned from several builders. Tap in multiple places until you here a nice bell like tone. Then, hold and feel for stiffness with the grain and the width of the grain. Then press down on the bridge area, and you should see a very localized area move at the same time. Maybe 3-4" in diameter of the bridge should move in unison when pressed at the bridge. If not, you can thin the perimiter of the top. I usually end up removing more material from where the tone bars and finger braces meet the X to get that nice ring. But then again, I've only built a few guitars, but have seen lots being built and have been able to get my hands on lots to test. Nothing is 100%, but at least it is something to shoot for.

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Tracy
http://www.luthiersuppliers.com