Builders: "Tuning"...What method do you use?

[invguy921]

I must say that I am simply amazed at the process that is used by you gifted builders to accomplish the aesthetic characteristics of gorgeous guitars. The more I learn, and the more examples I see, the more certain I am that I could never build one of these things lol. We'll leave that to the experts.

So my question revolves around the process of "tuning". I personally would love to hear how you guys go about achieving the final tone of your guitars? Of course I do understand that bracing changes things, but have never learned which part of this process is most effective, and I realize there will be a LOT of opinions on this.

I have seen that many builders seem to tune their tops as they go along, and possibly some tune the boxes after the build is well along, or both. Some builders use electronics of some kind to achieve optimal tone, some use just good old fashioned experience and good ears. I would love to hear some of your comments on this. I think inside of this discussion most of us will learn a lot about how "signature" tone is achieved.

Thanks in advance to all of you who join in this discussion!

[Alan Carruth]

As you say, there are several ways to 'tune' the guitar. Everybody has their own preference, from 'no tuning' (which I'd call 'subconscious tuning') through varieties of 'feel and tap' to more technical approaches such as 'deflection testing' and 'Chlandi patterns'. They all work for somebody, and I'd argue that, to the extent that they do work, they're all accomplishing more or less the same thing. Which one you use depends a lot on what you're comfortable with, and the sorts of measurements you like to take.

It's good to keep in mind here that if you're building to some version of a 'standard' design a lot of the work has already been done for you. Generations of makers, each trying to come up with something a little better, have fine tuned the structure to get very close to a good sound. If you use decent wood, and work carefully, you're almost bound to end up with something that works pretty well. That's why manufacturers can make reasonably consistent guitars in the thousands using so variable a material as wood. They know they're going to end up 'close' to a given sound every time just by being reasonably careful with materials and standard dimensions. Tuning is, in a real sense, only of much use to individual makers, for whom 'close' isn't close enough, or who wish to exceed the capability of the average production guitar on a more consistent basis.

This is why I think of 'no tuning' as being simply a subconscious version of the more active methods. Carving until the braces 'feel right' is similar to deflection testing with weights, but the data and records being relied on are not conscious. The brain and the senses pick up a lot of stuff we're not aware of, but we rely on it all the time.

I use the 'Chladni' method of tuning. This is a sort of 'tech' version of 'tap tone' tuning, where the different resonances of the top, and often the back, are activated in some way, and the pitches or other characteristics 'tuned' to some scheme that is felt to be desirable.

With tap tones the resonances are driven simply by tapping the plate. What you hear is whichever modes can be driven from the tapping point, are not active at the point where you're holding the plate, and that are audible where you've got your ear. You sort everything out by ear, and determine through memory and experience what works to make a guitar you or your customers will like. It can take some time to learn to do this, but it is simple to implement, and requires no special equipment.

Chladni patterns are formed by driving the plate with a single-frequency signal that is generated electronically. The plate is supported with soft pads at non-moving 'node' points, and sprinkled with something like sawdust or glitter. The powder bounces off moving areas and gathers on the 'node lines' in between . The resulting patterns tell you something about how the mass and stiffness of the plate are distributed, and the frequencies give a bit if insight into the overall ratio of stiffness to weight.

The 'free plate' frequencies and patterns are related to the resonant structure of the assembled instrument, but not in any simple way. If you could make two top and back sets that were 'the same', and glue them up to 'matched' rims, you should end up with 'identical' guitars. However, since even sister sets of wood will be somewhat different it's very difficult, and maybe even impossible, to make identical sounding guitars this way. Still, with care, you can get 'arbitrarily close'.

This method does require some equipment, most notably, a signal generator and amplifier. These days you can get apps that will make the sound, and an amp that puts out 15W or so is not too hard to come by.

The biggest advantage of this system, IMO, are that it is easy to keep records of what you've done to find out what works, and it's easy to teach. This is because, like deflection testing using weights, you're generating objective data.

Again, there is no 'right' or 'wrong' way to get this information. The 'best' way is the way that works best for you. In the end, as I said, since we're all trying to make 'better' guitars, to the extent that any of these systems work we're all doing the same things. We're just looking at them from different viewpoints.

[jessupe]

One thing I will say is that I dislike the term "tuning" as it implies some sort of procedure that is standardized and mechanical, as if turning a machine head slowly to 440 A. I much prefer the term "plate optimization".

[Alan Carruth]

The etymology of the word in this connection is interesting.

Model T Fords used a magneto ignition system. There was a separate set of points for each cylinder, which had to be properly gapped. These acted like buzzers to convert DC to alternating current that was stepped up in voltage to make the spark. The pitch of the buzz was related to the size of the gap, so an easy way to set that was to use the pitch rather than measure the gap. When the pitch was around middle C~261 Hz, the gap was correct. Thus the ignition could be optimized by the use of a C tuning fork, and you would 'tune up' your car. The pitch itself was not important; most likely nothing on the car was going a 261 RPM or whatever. It was simply an indicator that some other condition had been met which did matter.

[redir]

I started using deflection testing fairly recently and I like it because I think it helps me establish a baseline that I can tweak from there. I'm still in the process of collecting data to make anything meaningful from it. Prior to that I always thinned out to what I call the sheet metal tuning, shake the plate and thin it till it gives you that sheet metal wobble tone.

In any case the only 'tuning' I do is after the box is closed. And that is mostly in the form of thinning the top around the lower bout perimeter. In some cases I've tuned the top after the guitar is finished and strung up by shaving braces.

I honestly don't have any idea what to look for, I just do it, try and remember it, and if I get a guitar that sounds great then I attribute tuning it to it.

[TEK]

I am glad you asked this question Mike because I am also interested to hear what others have to say about how they handle top tuning.

As a hobby builder this has been one of the "secrets" that I have been in the dark about. My first couple of builds I simply went by a thickness as I had no idea what I was looking for. I flexed, tapped, shook and braced it to what looked right. Being a new builder, I wanted to build different guitars with different types of wood which made for a very slow learning curve for me.

After a couple of builds I started shooting for a certain deflection of the top while thicknessing. This got me at least to some sort of standard to start with. Once I get the top braced I start the tapping, flexing thing again while shaving braces. I also started weighing the tops once I get them where they start feeling and sounding right to give me a sense of where I am.
I feel like this is all seat of the pants method of building but my way of thinking is, until the top is glued on the rims with the back, and neck installed and fingerboard glued down, everything is going to change.
Of coarse a light top with the right amount of deflection doesn't always mean great tone. This is what I am curious to hear what the pros have to say about this process. At the rate I am going right now it will take me years to figure out what I am doing.
Travis

[redir]

Originally Posted by TEK

At the rate I am going right now it will take me years to figure out what I am doing.
Travis

I hear ya! I built my first guitar 25 years ago, the 50th was just last year and there was a few years I built nothing. Only now am I starting to get a modicum of understanding in all this.

This forum has actually helped quite a bit, and perhaps confused quite a bit too.

[JamesO]

I build recreationally as well. I started by using the method John Mayes demonstrates in his Advanced Voicing DVD, which is to listen for a certain amount of resonance and decay when you tap the top unattached from the rim while holding it at a nodal point, working on the braces until you get there. It's a great DVD and I think a great starting point. Words can't replicate what you hear, so I'd recommend getting it so you can listen to the changes as he works the tops.

Another method is presented in Trevor Gore's books, which is to specially look for some targets once the guitar is completed and to fine tune things from there. You're listening for where the top and back are frequency-wise when you tap them, as well as their relation to each other. I've picked and chosen from the material presented there.

On my most recent guitar, I got the top to a good starting point, glued it to the rim, and listened from there. Not for specific frequencies, but for a quality of resonance when I tapped the top in the bridge location.

[TEK]

Originally Posted by redir

I hear ya! I built my first guitar 25 years ago, the 50th was just last year and there was a few years I built nothing. Only now am I starting to get a modicum of understanding in all this.

This forum has actually helped quite a bit, and perhaps confused quite a bit too.

This forum has been instrumental (ha) in helping me also. Thanks to all who contribute so much of their knowledge.
Sometimes I feel like there is some " hocus pocus" going on when some talk about their methods of tuning but whatever works for them.

Dana Bourgeois has a video out where he explains what he does while he works on a top. He goes by feel and sound and he makes some great sounding guitars.
Travis

[Alan Carruth]

I took part in a workshop with Dana a month or two ago. I brought along my signal generator (with his permission, of course) and checked out the demo top he brought, as well as some of the tops of other participants. As expected, the tap tones we heard are the main resonances that Chladni patterns showed.

Dana's way is quicker, once you get the hang of it, but loses some detail that I think is important. I've been working lately with a 'matched' pair. By the tap tones you'd say the tops were identical, but the actual modes are a bit different in shape, and one pair is swapped in order. The two guitars sound different in playing tests; not by much, but still...

[ChuckS]

I know Alan's method has worked really well at least once 😀

[invguy921]

Originally Posted by Alan Carruth

I took part in a workshop with Dana a month or two ago. I brought along my signal generator (with his permission, of course) and checked out the demo top he brought, as well as some of the tops of other participants. As expected, the tap tones we heard are the main resonances that Chladni patterns showed.

Dana's way is quicker, once you get the hang of it, but loses some detail that I think is important. I've been working lately with a 'matched' pair. By the tap tones you'd say the tops were identical, but the actual modes are a bit different in shape, and one pair is swapped in order. The two guitars sound different in playing tests; not by much, but still...

Alan, thank you for the lengthy discussion points you have provided here. Really insightful and helpful.

Originally Posted by TEK

I am glad you asked this question Mike because I am also interested to hear what others have to say about how they handle top tuning.

Travis, I'm sure there are lots of us who wonder about this. Certainly all of us who have played a few guitars by various builders find a "signature" tone that seems to follow that particular builder. I'm optimistically hopeful that some of the other veteran builders will chime in on this thread. I don't think anyone wants to steal someone's secrets, but it would be nice to hear the process some others use.

[murrmac123]

My gut feeling is that great builders, just like great guitar players, are born, not made, and that no amount of scientific hokery pokery will compensate for the absence of an innate instinctual realization of what is required.

[Halcyon/Tinker]

We're in disagreement on that.

[Tim McKnight]

Originally Posted by invguy921

I'm optimistically hopeful that some of the other veteran builders will chime in on this thread. I don't think anyone wants to steal someone's secrets, but it would be nice to hear the process some others use.

Hi Mike,

I doubt you will get much feedback from the Somogyi students. Ervin asked us not to share what we were taught. Out of honor and respect for his wishes, I will respectfully decline from commenting about his tuning methodology. I can say that his methods work quite well when applied correctly.

Over the last 25 years I've used a lot of methods including; building directly from engineered blue prints, Chaladni tuning by Alan Carruth and Mark Blanchard, Gore's falcate methods, John Mayes methods, Kent's flop tuning, tap tuning, John Greven's tactile tuning and probably a few others that are slipping my mind. There are lots of ways to arrive at the final destination with no absolute right or wrong way to get there.

For the last decade I find myself using a combination of what I learned from Ervin and John Greven almost exclusively.