#16
|
|||
|
|||
Quote:
IME over the decades --in whatever discipline as I have been a backyard wrench and hack musician since a wee little lad-- I have learned that a true craftsman is the healthy critic, the scrupulous developer, and honest debunker who freely dismisses even his own "findings" should they fail to hold water. Thank you for being the true craftsman that you are. Edward |
#17
|
|||
|
|||
Quote:
|
#18
|
|||
|
|||
Found a nice vintage Guild 12 string with recent neck reset, and other work done. It's sits somewhere in USPS limbo awaiting delivery.
|
#19
|
|||
|
|||
It has been shown that hemicellulose does degrade with age in any wood. The first article I read about it cited study in a publication for furniture restorers, so it's not some 'magic' of Strad's. Since his instruments are pretty old, they've seen more hemicellulose breakdown than many others, but not all that much. The normal rate of breakdown is about 1%/decade, iirc.
As Wade says, current research does call the innate superiority of Strads into question. Many of the folks who are most vocal in denying this are those who stand to lose by it; dealers who live on commissions and people, or consortia, who own Strads. You can't expect them to say otherwise. Either the quality of 'projection' of great instruments is something real or it's not. It's possible that people who know they're listening to a Strad simply hear it as different; this happens all the time, and it's the reason why we need to do 'blind' tests. THe best 'bind' tests say there's no difference. If that's the case, the 'projection' of a fine instrument is all in the mind of the beholder; it's not real. There are things one could think of that might make a given instrument audible at a greater distance than another, even if the actual sound level is the same. For example, our ears are more sensitive to sounds in certain ranges of frequencies, so if a Strad put out more sound in that range than, say, a modern instrument, you could compare them and find that out. There are other qualities of sound that might have similar effects, and these could also be measured. Joseph Curtin, one of the finest modern makers, talked about this in one article. He had a violin in his shop that sounded just like a Strad, but nobody liked it. Since spectrum measurements showed it to be a good match as well that was not the reason. It took him, and physicist Gabriel Weinrich, a lot of time and effort to come up with a test that could tell them why. Eventually, by cutting the player out of the loop, they were able to figure out that the instrument only put out half the level of sound for a given input of energy as a better one. Players normally compensate for this sort of thing automatically, so in normal listening tests it didn't show up. Listeners thought it was a great instrument, but players didn't like the fiddle because it was hard work to play it! So it's not always obvious what makes one instrument better than another, or easy to find the cause, but unless you believe in leprechauns there's got to be one. Rather than simply assuming that Strads are better, and looking for some difference, we need to find some measurement that shows how they're better. Then we can work out the physics and lutherie behind it. Maybe mineralization of the wood has a real effect, but since plenty of studies have not backed that sort of thing up, I'm skeptical. Last edited by Alan Carruth; 12-26-2016 at 02:54 PM. |
#20
|
|||
|
|||
Quote:
The fact that the lead scientist only undertook this study after meeting Nagyvary indicates to me that there's a strong possibility of confirmation bias involved. That doesn't mean his data is faked, but those expectations of certain results can guide both the design of the study and the interpretation of the results. Professor Nagyvary has the burning inner light of the true believer, and he must have impressive personal charisma, because he's roped in all sorts of followers over the years. Yet the instruments produced under his guidance haven't exactly set the world afire with any impressive musical qualities. As they say in Texas, he's all hat and no cattle.... Wade Hampton Miller |
#21
|
|||
|
|||
The research featured in the NYT article has flaws to be sure, but is right to highlight the role of hemicellulose loss, as has been mentioned in previous posts. Some of the best work on this, IMO, has been done by the researcher E. Obataya (ref below), who has looked at both natural and artificial ageing (the latter AKA thermal modification, discussed ad nauseum, eh?). As it turns out, ageing only moves the physical properties by a few % points, but that is enough change to make the acoustic differences that folks hear. There is a lot of info, in Obataya's several papers, but in a nutshell:
1) Losing hemicellulose will reduce density without reducing strength, up to a certain point. It's like punching holes in a beam to lighten it - it works until it doesn't. 2) Hemicell loss will also reduce the abiliity of the wood to bind water vapor, relative to new wood. This will mean that the moisture content of an aged piece of wood will literally be drier than a new piece, when it is in equilibrium at a given relative humidity. Thus, an aged instrument side by side with a new one will have a lower moisture content, period. 3) Moisture content is incredibly important for the physical/acoustic properties of modulus of elasticity (stiffness, in shorthand) and damping. Spruce wood in equilibrium at a comfortable relative humidity (45-50%) will have a moisture content of about 8-9 %. Aged spruce at a similar relative humidity will have a lower moisture content, just a few points lower. However, spruce wood has a maximum of MOE, and and minimum of damping, at about 6% moisture content. Tonally, this is a "sweet spot" for maximum resonance. BTW, This is also why tone changes with seasonal swings in humidity, and why guitars sound best just before they crack, as the saying goes. 4) Thus, aged wood will have higher MOE, lower density, and lower damping . The first two factors increase the velocity of sound in wood, and lower damping will increase both volume and sustain (all other things being equal - build, design, and so forth). Taken together, these individually small differences can make a difference to sound quality. OK, The last sentence is an opinion, the rest isn't really controversial. From my perspective, the consequences of hemicellulose loss are the primary effects of ageing done well, or thermal modification done well. It ALSO turns out that some of these effects may be reversible if the wood is exposed to high moisture, but I'll leave that to the interested reader, or the collector of rare instruments Cheers, Dave Olson Below is a recent reference from Obataya, there are several more from which the above points are summarized E. Obataya. The effects of natural and artifical ageing on the physical and acoustic properties of wood in musical instruments. Journal of Cultural Heritage (2016) Last edited by varve; 12-26-2016 at 10:07 PM. Reason: clarity ;) |