"Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

For guitars of the straight waisted variety (or reverse offset).
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by timtam » Mon Jan 07, 2019 6:44 pm

The study I referred to from amongst those by the Leonardo project investigated classical guitars using a similar methodology, and addressed a similar question to the Carcagno study at the top of the thread ...
"What they did was to build fifteen classical guitars of the same type (based on a Torres FE19 model). All fifteen used equivalent quality European spruce for tops and braces. The sides and backs of five instruments were of traditional, tropical woods and the other ten were each a different, non-tropical (and therefore 'non-traditional') wood.
...
To quote LGRP, “Experienced guitar players and listeners were unable to distinguish tropical from non-tropical at better than chance levels."
(when blinded)
https://hazeguitars.com/blog/listening-tests-tone-woods

A difference was the choice of woods, viz. the specific inclusion of non-endangered species for the back / sides, for comparison to traditional woods (eg rosewood, ebony, mahogany and Spanish Cedar.).
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by Telemnemonics » Mon Jan 07, 2019 10:17 pm

sookwinder wrote:
Mon Jan 07, 2019 6:05 pm
we have to be careful here not to conflate two distinctly different questions...

- does the back wood choice of an acoustic guitar, in itself, produce repeatable and recognisable differences of sound quality (taken from the paper in the OP)
- can other types of woods (that are not endangered) be used to produce an instrument that is equivalent and acceptable to existing manufacturing materials and player expectations

for me the answer to both is yes.
I would agree with both those points.

The endangered species discussion is really a whole nother animal, even though they are related.

I've played a whole lot of different acoustics and in the end concluded that I prefer laminated RW back and sides, FWIW.
That might kill my credibility though!
I also (used to) shave the bracing on my own acoustics, to dial in the sound in conjunction with other mods.

The idea that hearing good tone from alternative back & sides woods means B&S woods have negligible effect on tone is foolishness.
But in the misinformation age every argument gets its followers!

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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by timtam » Mon Jan 07, 2019 10:45 pm

The authors of the Carcagno study also have an online listening test that anyone can participate in. You listen to the 6 different guitars and test your ability to tell them apart. They have the same construction, except for the backs and sides. The back and sides of the six guitars are: Brazilian Rosewood, Honduras Mahogany, Indian Rosewood, Maple, Sapele, and Claro Walnut.

See under 'Online tests' ...
http://www.psych.lancs.ac.uk/hearing/th ... xperiment/
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by DeathJag » Tue Jan 08, 2019 6:09 am

This is a really cool direction. When I get home, with big speakers I’m going to take the test.

Reminds me of the dude at the drum store’s standpoint. He said in the 50s and 60s no one cared (or even knew) what wood was used to make the drums, they were just made well and were heavy. He said all this stuff about maple vs birch vs other woods has only been in the past few decades.

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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by sookwinder » Tue Jan 08, 2019 7:27 am

Just to throw another talking point into this stew or fire or gumbo or what ever it is....

Many acoustic instruments that are made of wood take time to "come alive", take some playing to get the best sound out of them. This has applied to violins over the centuries as well as acoustics in the past 100 years.

I was reading recently that some luthiers/builders decide to use cedar instead of spruce as the top wood to get this "breathing" earlier because the cedar is a softer wood. That way it may only take 5 years rather than 20 years to get that "old world" sound that customers are wanting.

Going back to the original posting and the "paper", just wondering if any consideration was made to that fact that the instruments "tested" were all newly manufactured and in no way "run in". I suspect not.

Again ... a paper has been written without the niche' knowledge that trainspotters like us take for granted.
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by øøøøøøø » Wed Jan 09, 2019 9:12 pm

1) the methodology in the original article was garbage

2) RE: the other study, I was disappointed to find that when I listened to the YouTube video, it was very easy to tell (even though I listened blind) when the guitar changed, and when the substitute woods were used.

I was kind of hoping to at least get to wrestle with my own confirmation bias a little, and to get to say things like "well, if I were PLAYING i might be able to tell" or "grumble grumble, lossy YouTube codec" but nope. Super obvious even from listening in this less-than-optimal format.

Especially in the way the guitars excited the room (which you could tell even by just the ambience of this simple recording). Almost all of the substitute woods were clearly inferior in terms of projection and timbre. And this was obvious listening. There was one substitute wood guitar toward the end that I actually thought was much better than the others (I think it was the walnut one).

I was "watching" the video in a different browser tab. And whenever I'd think "hmm, that sounds kind of dull" I'd switch tabs on my browser and see one of the funny looking guitars.

I thought the very first guitar and the one at 1:44 sounded best of all. The guitar right after the one at 1:44 (the one at 2:01) sounds like a wet cardboard box in comparison.

The player was wonderful, though, and her Villa-Lobos was great!

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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by timtam » Fri Jan 11, 2019 10:37 pm

sookwinder wrote:
Tue Jan 08, 2019 7:27 am
Again ... a paper has been written without the niche' knowledge that trainspotters like us take for granted.
This is an interesting comment. I understand it's easy to conclude that scientific experiments on guitars must be done by boffins in white coats with little real understanding of guitars. But the reality is mostly otherwise. The nature of how scientific research is conducted is such that research on subjects such as musical instruments is mostly conducted only by instrument afficianadoes, who play them .. and who just happen to be scientists as well. The reason for this is that such research is not really taken seriously by mainstream academic science. Only people who have a passion for it tend to do it. It is akin to career suicide for anyone wanting an 'important' career in academic science. The marker of success in scientific research is research grant funding, which leads to journal publications, then to promotion and status, then to more funding ... in a sort of self-fulfilling circle. There is no serious scientific funding body that will give its scarce funds to someone doing research on guitars. The bodies' funds usually come from governments ... but what research the money goes to is decided by other scientists (all of whom are doing more 'important' research). So guitar research is mostly left to academic engineers and physicists who do it because they love it, can do it with little or no funds, and have given up on the idea of being very successful.

And that's also the reason why there is so little scientific research on guitars, particularly solid body electric guitars (associated with 'rock and roll' and even 'heavy metal' !) - because there are so few people willing to prejudice their career to do it. And there would be few department heads willing to let their staff pursue such research.

In other areas of science there is as much research done in industry as there is in academia. Unfortunately there is little or no scientific research done by guitar companies. Mainly because the market has never demanded it ... and possibly also because it would contradict most of the guitar mythology that marketing departments like to perpetuate to a mostly-gullible market. Companies have a vested commercial interested in the persistence of nonsense.

So ... the people doing scientific research on guitars are mostly transpotters just like us. ;)
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by sookwinder » Fri Jan 11, 2019 11:58 pm

I am sorry I totally disagree.

I worked (as my main area of activities) as an acoustician for 15 years, the partially as an acoustician for the next 18 years.
FWIW, something you may relate to, I worked on the HAMER HALL and the Melb orchestra rehearsal hall projects back in the day.

I was just a shit kicker acoustician back then, but I knew music, I knew musicians ... but I was the only one in the entire team who could say that. The rest of them, PhDs, and other engineers/scientists all brilliant people, but they had no idea about the minutia of musical instruments or even the foibles of musicians. One of the PhDs who worked on these projects years ago, didn't like /enjoy music. Yet he had to make decisions that directly affected "the sound" of the auditorium and rehearsal hall.

A friend of mine (also an acoustician ) who managed a large acoustic team for a building designer/manufacturer has a subordinate who was deaf! (yes that was not a typo, he was deaf)
Yes he knew all the theory, knew all the design factors, formulas, materials to use etc, but when it came to the client asking "what do you think, does design #1 or #2 sound best?" he could give an answer based on the science but not based upon just listening to it.

(In a way it was very similar to the stories about Leo Fender, designed great amps and kept on trying to make them cleaner, when the musicians wanted them with distortion).

In my 35+ years of working in the acoustics and engineering industries (in Oz and overseas) where I would have encountered 1000s of engineers and scientists, I would guess a dozen of them were musicians who had the knowledge/background/experience to relate music and musicianship with the science and the engineering.

Lean pickings I can tell you ... lunch time conversation were NEVER about what size capacitor should I try on my strat. In fact my current manager, an electrical engineer was adamant that only the value of a capacitor would affect the tone in an electric guitar, until I asked him about the amplifiers he built years ago.... then is dawned on him that the same justification he used to choose the caps for his amps may also be used when choosing them for electrical guitars.

With all due respect your "understanding" of how research (academic and industrial) is done, it is nowhere near the mark, it is nothing like what you see on TV or movies. You do not have boffins in white coats who also happen to be an expert in the design of electric acoustic guitars, hiding in small acoustic labs, just waiting for someone to ask "is the colour of the whammy bar tip going to affect the sound quality"

In the vast majority of cases the over riding factor that determines how an experiment, survey, research project is conducted is the budget or available funds. Once you know this, you can determine how many man hours and then determine materials and a time frame. If it is super urgent then you just quote a higher figure and it is a take it or leave it scenario.

The area I now work in, the auto industry, also has similar situations where the experts who work on project have no understanding of the use for those products. case in point - sound systems, infotainment systems for vehicles. My pet annoyance is that when the knobs on a car stereo system are set at neutral, the sound that is produced is nothing like the music being played. Yes you can say "oh the interior of a vehicle affects the sound" .... yes exactly, so you tweak the system to take the absorption factors of the seats, carpet, finishings and occupants into account to enable the neutral EQ of the system to sound correct.

I had an "discussion" with one of our electrical engineers who works/worked on vehicle sound systems and asked her "why do our sound systems always need to be drastically EQ'd by the driver before they sound half decent?" Her response was "the way you want to hear it maybe different to other people, so your way in not necessarily correct".
She could not understand the concept that if there is a piece of music which one has recorded yourself, you know what it should sound like and like wise the audio system should be able to reproduce that (as best it can) in the neutral EQ set up. Just totally went over her head.

Mind you when you listen to the "mixed tape" CD that they would use to "check the infotainment systems" one can well understand why the vast majority sound shite in the neutral EQ position

Again experts doing their job perfectly as required, yet that have no understanding of the actual usage of the end product.


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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by sookwinder » Sat Jan 12, 2019 12:13 am

One more example of experts not understanding the reality.

Years ago I worked in Hong Kong and we had to do the acoustic design for an auditorium and then confirm by testing that the building had met the specifications. So the auditorium was built, it then came time to test the "intelligibility" of the sound within the auditorium. Up front, middle and rear seating. (at this point I arrived and was involved in this part of the work)

Bruel & Kjaer have equipment that allows one to measure the intelligibility of a space like a theatre or auditorium.

Basically the equipment measures the sound emitted at point A with that measured at points B, C, D , E etc. Using language criteria a comparison is made and a result is achieved. In short it works out how easy it is to understand what someone is saying on stage at the various seating positions.

The problem is that this testing specification methodology was stipulated in the contract (had been agreed to and sign 7 years prior) and while it may have worked perfectly in any European language country, the equipment and methodology had never been validated for Cantonese or any other Asian language.

So yes, the design of the auditorium was done correctly, yes the validation of the building was done correctly as specified in the contract and it passed with flying colours, but we had no idea what the intelligibility factor was when the local language of Cantonese was spoken ... which was the main reason for the design and validation in the first place.

Just because they wear white lab coats, doesn't mean they know everything.
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Re: "Effect of back wood choice on the perceived quality of steel-string acoustic guitars"

Post by timtam » Sat Jan 12, 2019 12:31 am

sookwinder wrote:
Fri Jan 11, 2019 11:58 pm
With all due respect your "understanding" of how research (academic and industrial) is done, it is nowhere near the mark, it is nothing like what you see on TV or movies.
It is not my "understanding" of academic science from TV and movies. It is my lived experience of it, as an academic research scientist (not working on guitar science ... as I have been well funded). I did not talk about industrial acoustics, as I have no direct experience of that.

The people I am talking about are the academic scientists who publish in guitar science. Most of those who I have any knowledge of would be deemed guitar nerds. So by the sound if it, clearly different to the type of people you have encountered in your work.

That is not to say that these scientists' work is always rigorous. In fact as a result of the factors I mentioned they are sometimes those scientists who never quite made it in 'big science'. Few academic scientists would choose guitar science as their area at the start of their research career. Also as I mentioned their work is often unfunded. So things that we might like to see done differently in such studies were possibly not done simply because the funds were not available. Or that the only way the study could get done was as a student's Masters or PhD project, in which case it had to get done not only with little funds but also in a short period of time. Many academic scientific studies are done the way they are for pragmatic as well as scientific reasons. Finally, questions are never completely answered by a single study. You do a study, analyse and interpret the results, publish them, and then decide on the next question / study to further fill in the bigger puzzle.

Anyway, don't assume that the failure to perform the 'perfect' study reflects a lack of sufficient guitar nerdiness. ;)
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