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Yeah, there is a lost moment between two of the segements and yeah we strain to see the chalkboard but man-o-man I was in hog heaven. So much of what Ervin said just made sense to me and there's just so much more I want to understand. I've got to find a way to get to one of his classes!

Thanks to Lance, Brock, and Ervin for making this happen.

Hats off to Ervin for his listening and teaching skills. I wish he was one of my profs, way back when.

Tom Armstrong

To my ear the fundamental note stayed the same when the bridge was attached.

The difference seemed to be that low frequency harmonics (overtones) seemed to diminish when the bridge was attached.

Is this because the extra mass attached to the soundboard requires that more energy be expended to to get the top to move enough to produce the overtones?

I don't know. Just theorizing.

Bobbob_connor39087.9090162037

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Bob Connor
Geelong, Australia

[QUOTE=bob_connor] To my ear the fundamental note stayed the same when the bridge was attached.

The difference seemed to be that low frequency harmonics (overtones) seemed to diminish when the bridge was attached.

Bob[/QUOTE]

That's what I heard as well. I was surprised that the difference wasn't more dramatic, in a way.
John

moved to new topic
jtkirby39088.3433796296

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Jim Kirby
kirby@udel.edu

Jim, I think you can just start a new topic in this forum.

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Instead of keeping a soundboard that you like, could one simply glue the top to the sides, then use a mic to record tap tones at various sites? This way, you could finish the build and find out how it really sounds on a guitar and compare when you build the next one.

On Ervin's builds he attaches the top first and voices it with the back off. It is attached to the rim when he voices.

I prefer to glue the back on first to keep the box really ultra clean (I don't have 40+ years of experience like he does... and can't control the squeeze out quite the same way) so I use a tapping mold to do the voicing (like the one he shows in the videos) before attaching it to the body.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

[QUOTE=Brock Poling]
On Ervin's builds he attaches the top first and voices it with the back off. It is attached to the rim when he voices.

I prefer to glue the back on first to keep the box really ultra clean (I don't have 40+ years of experience like he does... and can't control the squeeze out quite the same way) so I use a tapping mold to do the voicing (like the one he shows in the videos) before attaching it to the body.

[/QUOTE]

I don't know if you were replying to what I said or not, buf if you did, I meant later in the movies... as you can't know what exactly you've achieved with taptones until you string the guitar. Let's say you carved your braces and you "think" your tap tones are good, you string the guitar and it sucks... what do you do from there? Depending on which area you tap on, you get something different, but what are we looking for exactly at one specific location according to the bracing pattern? I think that's when you need a lifetime experience when you tried a little of that there once, and a little bit of this another time to find out what it does. But let's say you build a guitar and finished bracing the top and glued it to the sides (or not). If your recorded tap tones at specific places, just to have a referential, then finished up the guitar and found out that it was GRRREEEAT, thenI guess, one could try bracing another guitar in a way to match the taptones of the previous one. Am I making sense?

true enough... it will take a lifetime (and probably then some) to figure this out.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

   While I have a lot to learn, generally speaking, I feel that I know how to build a guitar now. I have absolutely no idea how to make it sound like I want. That is what I hope to learn from you.
My latest guitar lacked in bass response. Will I have a good idea how to predict and/or avoid that lack of balance after your course?[/QUOTE]

Hi, Steve S. & everyone else out there: I certainly hope and expect so. That's the whole point of the class, really. It's also a main reason that I do NOT want to encourage beginners to take this class: they are too busy internalizing the basics to focus on "over-and-above-the-call-of-basic-duty" stuff, such as independent or critical thought. The learning needs to occur in stages and first things need to come first. (I really try not to come off as sounding too sage-like in saying things like that.) Cheers, Ervin Somogyi

[QUOTE= . . . and yeah we strain to see the chalkboard but man-o-man I was in hog heaven.
Tom Armstrong[/QUOTE]

Dear Tom: oink. I'd love to have you in class sometime. Cheers, Ervin Somogyi

[QUOTE=Hesh1956]

You said in your introduction the following: “(1) the setting of the body’s main resonances through the manipulation of its main plates, and (2) the manipulation of the top’s ability to engage in its principal vibrational modes.”

I found this to be a very good and understandable description of your objectives for your course offering. I also think that this is by definition the difference between building a guitar and “crafting” a guitar.[/QUOTE]

Hi, Hesh: Yes, I think you have it: it's a one-sentence encapsulation of something that could easily take years of experience at the workbench to explore more or less fully . . . but you've got the central idea. I've talked with you on the telephone and I'd enjoy having you in class sometime. Cheers, Ervin Somogyi   

I think the information in the class is great!! It is the result of applying science to the art of crafting a great guitar. Not science in the sense of doing exhaustive studies of the exact mode shapes involved, but looking at the basic scientific principles involved (main parameters involved in stiffness of a beam- the thickness cubed effect, the basic shape of the main vibration modes, etc.). In my life as an engineer, this was very often the approach that was most productive in giving direction to the attempt to understand and solve a problem.

I also was sorry to miss the end of the bridge addition segment of the lesson. I thought I heard a decrease in both the frequency and volume of the sound, an effect of the mass addition, more than the stiffness. The bridge is added to an area that is already pretty stiff- close to the center of the x-brace, and with the bridge pad already in place on the underside of the top. So intuitively, it seems that the mass effect would dominate over any changes to the tranverse resonance.

Bob J, and up to ten others (maybe more if I have time), I would be glad to burn a CD with the 5 discussion segments on them and mail it to you, no charge. Send me a PM.

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Gene

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