Official Luthiers Forum!

Hi everybody,

please check out this video posting on YouTube.
http://www.youtube.com/watch?v=Ajn0TmhvwCU
The late Benno Streu demonstrates how to find flaws in the tuning of the soundboard of an existing guitar (he was pretty famous in Europe in bringing historic classical guitars back to life - collapsed soundboards etc.).

There is a big controversy among European luthiers if Streu is up to something or if this is somewhat of a hoax.

His demonstration is very easy to understand and the "flaws" are easy to hear on this video. I would be interested what the opinions among the luthiers on this forum are about this matter. It supposedly works on steel string guitars as well as on lutes or mandolins etc.

In the middle of the video clip is a live performance of the famous "La Leona" of Torres. Feel free to skip, if this is to lengthy. The stills at the beginning and at the end of this clip are taken of the actual "La Leona" of Torres.

I appreciate your time and consideration. I am currently working on an extensive video project about fine guitar making.

Cheers,
Holger

Interesting that the luthier in the video is focusing on the symmatry of the vibrating nodes......not a large stretch from the emphasis Al places on the shape of the node lines.

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Formerly known as Adaboy.......

...or David Hurd's emphsis on the smoothness and symmetry of the patterns of displacement under load.....

I stumbled on it last week watching the Brune' piece about the little Torres. Since I don't understand German, and the subtitles left a little to be desired, I'm not sure I fully understand what he was getting at.

I tap my guitars a lot as I am "voicing" the completed box and thinning the top from the outside, usually the perimeter of the top, till I get the "bonk" that I am looking for. I also feel for deflection. No numbers, no note, only a sense that the top is resonant enough NOW, and call it done. If it is deeper knowledge than that simple exercise, I don't know about it.

I don't think Streu is communicating anything more than "if it sounds good, it is good" and that you can't do it with microphones, it is better done with your ears and fingers.

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https://www.facebook.com/profile.php?id=100008907949110

That's the way I've always seen it.

I've also read through some material on violins and supposedly the best violins have very symmetrical modes.

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http://www.PeakeGuitars.com

To me, all his "demonstration" shows is that guitar tops vibrate, period. He didn't show symmetry (just that both sides vibrate), or prove that symmetry produces better sounding guitars, or anything close - the short bit of his demo that showed both sides vibrating looked to me like the "node" (where the sound level increased when he touches it) was in a different place on either side of the guitar. I'm not saying that guitars with symmetrical vibration modes don't sound better - I really don't know yet, but I will require quite a bit more scientific evidence than this short un-scientific video.

To top matters off, he completely disses the use of any microphone as being useful for measuring sound - the best one ever produced (by Sennheiser) being at least 10 times less sensitive as a human ear, apparently, yet we can clearly hear the increase in volume that occurs when he hits the "node" in the video.....that used a microphone to capture the sound! That severely impacts his credibilty IMO.

Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

That is a great post, Dave!

It usually does impact one's credibility when they insist they're hearing things that can't be recorded...they have a word for that, I think. Doubly so if they follow that with a flagrantly incorrect 'fact'. We make microphones now that are orders of magnitude more sensitive than our ears.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Ok, I was going to keep quiet, but a couple of things.

First, Benno is dead. As far as I can tell, we don't know when the video was made. So criticizing him for his claims about microphones seems a little unfair. On top of that, I heard some obvious volume increases/decreases in the video. But who knows how things would have sounded in person? I don't.

Second, he's saying more than just that the top vibrates. He's saying that the top vibrates at various points (tone islands) at various pitches. He also said that he considered a top perfectly tuned when those islands formed a circle around the bridge, uninterrupted by dead spots.

I don't have a personal interest in how people respond to the video or to chladni patterns/top tuning, etc. I've replied simply because I thought some of the replies were a bit unbalanced. No offense meant to any of you.

- Flori

I watched the video again and re-read the comments and I can't find anything unbalanced in the responses. It seems to me that folks were just giving their honest opinion, which was asked for, about the video.

Just to be clear: I do believe the Chladni mode method is sound, and valuable. The part I take exception to is the introduction of 'magic' into the process with the microphone claim. Since it was a video for Gourmet Guitars, that claim was definitely false at the time.

I quite liked the rest of the video, and it appears credible, but the tendency for a lot of luthiers to play loose with their facts to inject a little extra mystique into the craft is a pet peeve of mine.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

The guitar sounds beautiful but where is the saddle? It looks like the strings go straight through the bridge. What am I missing?

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GEO
perpetual beginner

Many Classicals have no "Saddle" per-se.
The properly tied string forms its own saddle.

Thanks

John

I finally got to watch that video... I think I need to watch it about 50 more times.

What an amazing amount of knowledge and skill... and he is just scratching the surface.. Just a quick demonstration at a Resturant... Oh.. and by the way... Here is La Leona for you to plunk around with!

This guy is basically walking through what I assume is the "Ancient method" of voicing right there... and then relating it back to modern science!

"See how I can play this note and then find where it vibrates on the guitar"
"Now, I feel for where it sounds out and changes like this" (Rubs top.. sound changes)
"And I adjust these so they all are symmetrical around the bridge and sound out about the same loudness"
"And the best ones have such and such pattern around the bridge....."

Perhaps that is what Torres and those folks meant by "It is impossible for me to tell you my Secret.... It is something your fingertips have to communicate with your brain" -- they were feeling for vibrational patterns... but they didn't have the science at the time to actually explain what they were listening and feeling for... and it explains why they would work behind closed doors at odd hours and ran everyone else off.... Not because it was "Secret" but because you need to be fresh, in a good mood, uninterrupted... Even they couldn't always hear it or feel it.... You can't hear or feel this in a noisy workshop after 8-solid hours of planing and chiseling... your hands are stiff and your ears feel full of cotton... and you are worn out! You can't do this with a million distractions -- Your kids and the dog running in and out and your Wife telling you that she needs a jar of Jelly off the top shelf and the trash needs taking out and that we are out of Sugar... and then the Apprentice really needs you to hold his hand to feel it...

SO.. I basically realized by the end of the video that the "Voicing" I am doing is just basically random hand waving...

Thanks

John