Official Luthiers Forum!

Last Sunday Al Carruth presented to the New England Luthiers Mark Blanchard's presentation on using Chladni patterns to tune a guitar body. Mark's presentation, which all read to us and his extensive photos took a subject that has confused many of us and made it into a system that could be used by anybody.

I've known Al for several years and heard his presentation on Chladni patterns several times. Mark and Al both emphasize that the most important thing is to keep records and try to do the same tests in the same way each time. That way you will develop an understanding of which pattern shapes and frequencies make the best sounding guitars. At least to your ears. Al has emphasized the shapes of the braced pattern as the feature that he likes to concentrate upon. Mark, in contrast, has extended the approach to unbraced tops to help him decide which size and shape of guitar will work best with a given top.

Keeping your own records is the most important thing but Mark was kind enough to share with us which shapes and which frequencies he looks for when tuning a top. Theoretically, you could follow his recipe and build a guitar that sounds like a Blanchard. In practice, I doubt it since there is much that goes into a guitar. But, my guess is that if you did follow his recipe, you would end up with a pretty good sounding guitar.

An interesting observation I made was that both Al and Mark use a symmetrical bracing pattern. Mark uses a Larivee type pattern and Al uses a double X. It appears that getting the desirable Chladni patterns with a Martin style brace is a lot harder.

I certainly hope that Mark publishes his presentation in ASIA or GAL or some other accessible forum. There were some critical frequencies that I didn't get written down and the text was so well done that I'd like to read/hear it again.

So, thanks Mark and thanks Al for sharing this.

Yes! I was lucky to have attended this also and agree that the presentation took a topic I found confusing and synthesized it into a practice that seemed doable and very informative to maintaining a high standard of work. I will second Mike's thank you to Al and Mark, Thank you very much! I do have a question also for anyone set up to measure the patterns, is there a commercially available setup for powering the speaker and reading the frequency numbers? I know how to jerry rig one but would rather not!

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

I did a little more looking and found the info-LMI has the address for the maker of the signal generator on their website although they no longer carry them. In case anyone else was interested.

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

The unit described by LMI is quite expensive and would only consider it if you were interested in making a commitment to Chaldni patterns. There are other alternatives that will get you going. Madell
has a cheap function generator that works OK. It needs supplemental amplification like an old guitar amp. I have the EM1635 which cost $149.00. It covers the frequency range by using different bands and the band break is at 150Hz so that is a bit annoying.

I glad you guys found the presentation informative. My thanks to Al as well for sharing it with you.

I'm not sure about publishing it. It is really a narrated slide show, so all of the pictures would have to be included. It would take up a lot of space. I suppose it could be rewritten in a different format, but I won't have the time for that anytime soon.

Th signal generator I use was made by Don Bradley. I think he still makes a "new and improved" model. They are expensive but they were designed specifically for Chladni work so they are very convenient and easy to use for this purpose. I will try to dig up his contact info and post it here later. I suspect that there are quite a few used ones out there that are not being used. If you can locate one, that might be a way to get one at a good price.

It should be possible to make a guitar that sounds a lot like one of mine by following the "recipe" given in the presentation. Whether or not you will like that sound is another question. I build a lot heavier than most of what I have seen on this forum. It is a style that is not for everybody. The best thing to do is to use the Chladni data you collect to help you develop and hold on to the sound YOU like. That means putting in the time to collect and interpret a LOT of data from which to extract your own recipe.

Mark

 gee i wish i was there... not sure new york is considered new england though ... jody

Yea, Thanks Mark for having the "ghost" presentation for us. I was in Healdsburg, but a late Saturday night and guests staying over till Sunday prevented me from making it to the "live" presentation last August. Needless to say, Al inserted the jokes, but our favorite was when a picture of AL came up in the slides. It was really funny to hear Mark's narration in AL's voice introducing himself.

I have been "playing" with this type of tuning for years, and have been to many of AL's talks. I was really disapointed that I missed Mark's talk this summer. Everytime I go to one of these things I learn a little more. I don't know if I make better guitars, because of it, but I think I do make more consistant guitars because of this stuff. (I guess I could be making consitant junk.)

Thanks again Mark and Al,

(BTW Jodi, I was born in NY, and live very close to NY, (very western MA, the Berkshires) but they still let come to meetings.)

I, too, want to thank Mark for sending me that talk, and for allowing me to present it at the meeting. He's done a lot more data mining than I have, and presented the whole thing more clearly and in a more interesting way than I do. I second Mike's encouragement to make it into an article for GAL or ASIA.

As for building the tops heavy; that's what I do too. One of the things you can do with Chladni tuning is dial in the _back_ frequency so that it works with the top, which adds a lot of power in the low range. This allows you to use a heavier top and keep the bass balance andoverall output. A heavier top tends to be more stable, if it's done right, and i find my customers appreciate that.

Interesting. Both Al and Mark make heavy tops. They both use symmetrical bracing. The both graduate their tops. It has been said that the tools an artist uses directly influences the art. It seems likely to me, that these physical characteristic make it easier to get the Chladni patterns you want.

[QUOTE=Blanchard] I glad you guys found the presentation informative. My thanks to Al as well for sharing it with you.I'm not sure about publishing it. It is really a narrated slide show, so all of the pictures would have to be included. It would take up a lot of space. I suppose it could be rewritten in a different format, but I won't have the time for that anytime soon.
[/QUOTE]

Blanchard, Al
I can appreciate that your very busy guys, however.....
This would make a fascinating video, it is in effect very easy to make a slide show into a movie format and then adding a commentary would take a bit of effort, but not an out of control amount of work...overall
I would buy a copy of just such a video, and Im sure Im not the only one,,,,
An easier solution would be to film one of your presentations and sell that... as I said Im sure it would sell very well among luthiers...
Its just hard to hard start to finish comprehensive information on the subject matter.. that doesnt raise more questions than it answers....
If you do decide to releases something please keep us aprised...
Cheers
Charlie
Cheers
Charlie

Charlie

My talk at the Healdsburg show was videotaped.
I'm not sure if the tape is available but you might ask the folks at LMI about it.

Mark

As to heavy tops and tuning: I think there's something to that. One way to lok at this is that we're trying to get a certain balance between the bracing and top stiffness, so that neither of them is doing all the work, if you will. If you make the top thinner then the bracing will also have to be smaller to preserve the same balance, but that might end up making the top too weak. You can, of course, use heavy bracing on a thin top, but I'm not fond of that sound.

I will say that the way I do tops tends to emphasize the treble a bit, and you need to do something to bring up the bass. I usually do that by the way I tune the back, and, from what he said in his presentation, I think Mark does the same.

This is just another example of how there are lots of ways to make a good guitar.

On top thickness and bracing....

I have found that it works best if the top is the thickest in all the same places that the bracing is the heaviest (tallest). That means thickest under the bridge, under the X brace intersection, under the fingerboard, and under the upper transverse braces. The top will be thinnest near the waist and the edges of the lower bout, especially near the tail block.

I think this helps create the "balance" between top thickness and brace stiffness that Al mentioned.

It also makes it easy to see why I taper rather than scallop my braces !!

Mark