Mahogany as an "inferior" tonewood?

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Alan Carruth
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Re: Mahogany as an "inferior" tonewood?

Post by Alan Carruth » Thu Apr 27, 2017 2:21 am

Caribbean mahogany grows all around the sea of that name; a lot came down in hurricane Andrew in Florida years ago. It has been hard to get the wood from Cuba in the US, but maybe that will change. The first guitar I built with my teacher was made from Caribbean wood that came from Santo Domingo. It was difficult to bend, but made a very nice guitar, considering my inexperience. I read once that the Spanish ships of the line in the Great Armada were built entirely of Cuban mahogany. Just think...

Maple tends to have higher damping than the rosewoods, more in line with mahogany. Soft maple, such as the European wood or American Red maple, is quite similar to walnut wood. I always find it interesting that people characterize maple guitars as 'bright' and walnut as 'dark' when the woods are so similar.

hesson11
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Re: Mahogany as an "inferior" tonewood?

Post by hesson11 » Thu Apr 27, 2017 2:45 am

About the term "damping:" It seems somewhat self-explanatory, but I wonder if someone could elaborate on its meaning in regard to its effect on the sound of a guitar. Thanks.
-Bob

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Re: Mahogany as an "inferior" tonewood?

Post by Alan Carruth » Thu Apr 27, 2017 6:36 pm

Damping is indeed pretty much self explanatory: it's the rate at which vibration energy is dissipated within the system. What it means for the sound is not so simple. The problem is not so much in the guitar end: you can measure the wood and determine it's damping factor (with some reservations) and look at the sound of the assembled guitar to figure out how fast the vibration is being damped out and at what frequencies. The problem is relating that to the player's and listener's perceptions, which are far from simple.

Low damping systems have two things in common: they 'ring' for a long time once they've gotten started, and they have a well defined frequency. A material that has high damping, such as foam plastic or particle board, gives a short 'thud' when you hit it, with no discernible pitch. A piece of aluminum or glass can have a very well defined pitch, and ring on for a long time. Wood in general is between those extremes.

You have to keep in mind that the damping of a particular object will be the sum of all the things that can dissipate energy. This will include material properties, of course, but also other things such as the sound that is radiating from it. Something like a loud speaker may be made of materials that have low damping, but it doesn't weigh much, and has to move a lot of air when it moves, so it won't 'ring' when you tap it. This plays out in wood as well. I used to think that balsa wood had high damping until I got hold of a thick piece to test. It turns out that the wood itself is in the same general class as spruce for damping, but, being low in density a thin piece just hasn't the weight to keep going. This sort of damping is probably most important in the guitar top. Most of the literature I've seen on this says that the 'loss' to the system from sound radiation is 'small' relative to most other sources of damping, so it's hard to say how significant it is.

Wood is a complex material, and there are several ways aside from making sound that could dissipate vibration energy. Some of these could well vary with frequency. We usually measure the damping factor of wood by vibrating a sample at it's resonant pitch, but the exact frequency will depend on the size of the sample and so on. There's no guarantee that the number we get there, which is usually at a pretty low frequency, has any relationship to what's happening at other pitches. It could be that otherwise similar woods could have very different damping at high frequencies, for example, which might bear on the way the guitars sound.

Since damping tends to cut down on high frequency response you might think that a guitar made of low damping wood would have a lot of highs, and sound 'bright'. As it happens, though, Brazilian rosewood and Western red cedar both have notable low damping, and people often say that guitars made of those woods tend to sound 'full' or 'dark'. Maple and spruce, with higher damping, are usually said to make 'bright' guitars. It's difficult to reconcile these statements. It may be that the ear and brain are adding all of the energy in the overtones to the fundamental, giving the instruments with more overtones a 'darker' sound. It's possible, too, that since cedar and rosewood are darker in color, they sound 'darker'. The higher damping woods will tend to give a sound that both starts an stops more quickly, and that 'punch' might come across as 'brighter'. There are a lot of dimensions to this. It's not easy to sort them all out.

If you could make two instruments that were 'the same' except for the damping factor of the wood used it would be fairly simple to say what it meant in terms of sound. That's not easy, and may well be impossible. There has been at least one computer modeling study that looked at damping as one variable, and found that it had little effect. OTOH, the model was very limited as compared with a real guitar, which is an engineering nightmare, so it's hard to say how much weight we can put on that. Another study based on a different electronic setup did find some interesting things about damping. In particular, they noted that either too much or too little damping tended to produce sounds that listeners did not like. This could be one reason we don't particularly like aluminum or plastic guitars. On other hand, that study was on violin sound, and guitars may be somewhat different.

In the end nothing about the guitar is really 'simple'. That's what keeps it interesting (and frustrating!). ;)

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Re: Mahogany as an "inferior" tonewood?

Post by attila57 » Thu Apr 27, 2017 8:32 pm

hesson11 wrote:I must plead guilty to, perhaps subconsciously, thinking of mahogany (back and sides) as inferior to the more traditional rosewood. Anyone else?

...Do any of you think of mahogany as a "poor cousin" to rosewood, as I did? And is that fair? THANKS.
-Bob
I like mahogany for guitar necks, bracing and end blocs. It's also great for furniture. :) For back and sides I prefer rosewood. I can actually hear the difference. Mahogany usually lacks rich, deep, resonant basses, which I prefer. It usually has a thin, airy tone, which, to my ear is insufficient for really versatile classical guitars. It is often used, however, for folk and acoustic guitars. I think it is because of the different tonal characteristics of the steel strings, and because of the different tonal requirements. I'd say, steel strings have so many harmonics, that a decent rosewood back would yield a somewhat hazy overall tone, with not so easily distinguishable individual notes. As for mahogany, I don't say that's impossible to find a suitable set of mahogany back and sides for classical, but RW is more easily available, and, usually better for the purpose. In the case of the classical guitar, this purpose is to enrich and amplify the basic frequency as well as a wide range of harmonics. Nylon strings have a different, narrower range of harmonics than steel strings.

The whole matter depends, of course, on individual taste, too.

Talking about tonewoods, what do you think of maple for classical? As for me, I like maple for lute backs.I think maple is actually much better for that than flashy rosewood, which is now widespread. For renaissance or baroque music I prefer maple. Maple classical backs, however, are not to my taste. To my ear, their tone is even thinner than mahogany's. They have a "chirping" quality which is very characteristic.

And here is the question of cypress. It is often used for flamenco guitars, because rasgueado sounds more percussive with cypress back & sides. Still, nowadays "negras" (with RW back & sides) are gaining more and more popularity, and their tone is considered more "macho", with more bass, but with the right thickness keeping the tone dry, even hoarse a bit.

Attila :bye:
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Sweets with sweets war not, joy delights in joy...

William Shakespeare, Sonnet 8

hesson11
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Re: Mahogany as an "inferior" tonewood?

Post by hesson11 » Thu Apr 27, 2017 9:28 pm

Thank you very much, Alan and Attila. Alan, your clear-headed scientific approach, encyclopedic knowledge and endless curiosity always amaze me. Attila, much to think about there!
-Bob

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Re: Mahogany as an "inferior" tonewood?

Post by lux » Tue Sep 19, 2017 7:09 am

I recently had the opportunity to play through over a hundred classical guitars from the estate of a collector (I was helping to evaluate the collection). Many were hand-built one-of-a-kinds, but there were quite a few factory builds as well. Most were in "time-capsule condition." The guitars I played with solid mahogany bodies were among the finest sounding of the bunch. And that includes some guitars that would have been considered student models or intermediate-level instruments (Guild Mark III, Gibson C100, Goya G-17 among them).
So one of my observations is this: rosewood guitars are going to sound better when new, but mahogany catches up to a large extent over the decades. The sound of fully seasoned mahogany is different from rosewood, but not inferior. Water, as you might guess, has considerable damping qualities and it can take decades for tropical woods to lose the last of their residual moisture and get really crisp. I would say the sound of mahogany gains more definition with the passage of time. With the bass register, in particular, definition matters a lot. You can have two guitars that both sound "bassy" in terms of resonance, but if one is muddy and the other well-defined you'll easily hear the difference just playing some scales on the 5th and 6th strings.

Up until the mid-20th century, supplies of instrument-grade mahogany were plentiful and the exchange rate between the U.S. dollar and the Honduran lempira made the wood dirt cheap. And, of course, we don't highly value something that's low in cost...until the cost goes up. So back in the day, mahogany was often used for student instruments and "studio models' while professional instruments and "concert models" featured rosewood. Traditionally, mahogany backs were made without a center strip and with minimal binding/purfling and a basic rosette. Today things are different and a good mahogany guitar can command several thousand dollars. Quartersawn mahogany is generally rather ho-hum, so those guitars you see with burl or flame figure are most likely laminated. Sapele is not a real mahogany, but I wouldn't dismiss it as a second-rate wood, either. It's probably much easier to get instrument-grade sapele right now than instrument-grade Honduras mahogany and many respectable instruments have been made with it (it's a popular wood for beginning luthiers).

I also noticed the effect of finish on mahogany. The best sounding mahogany guitars I played were French-polished shellac or varnished rather than those sprayed with lacquer. One of the things that gives rosewood is high sonic velocity is its resin content. More open-pored woods like mahogany lack that. But with several coats of shellac really rubbed into the surface of the wood, maybe there is some compensational resin content that comes from the process of hand-finishing a guitar. Call me superstitious, but I don't think you'll ever hear the full potential of a mahogany guitar that's been entombed in a layer of sprayed-on nitro. A good guitar needs a finish that can breathe.

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Re: Mahogany as an "inferior" tonewood?

Post by GeoffB » Tue Sep 19, 2017 10:30 am

Hi lux, welcome to the forum. Could I ask you to introduce yourself here?

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Re: Mahogany as an "inferior" tonewood?

Post by JohnH* » Tue Oct 03, 2017 1:23 am

I sometimes even wonder if we can make a great sounding guitar using carbon fiber or "paper" for the back and sides as long as it is paired with good quality top and a skilled luthier.
Torres already did this experiment with FE14. A topic introduced by ChiyoDad on Sun Jun 08, 2008 drew three pages of discussion. Sorry, but I don't know how to add a link to a previous topic.
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Re: Mahogany as an "inferior" tonewood?

Post by Humphrey » Tue Oct 03, 2017 4:42 am

Torres made a famous guitar with a body of paper mache with a spruce top and found that the body had has less effect on the sound, the soundboard makes the guitar sound good or bad.

I like the figures and colours of Brazilian Rosewood, I made a simple Barok guitar, the body of flamed maple and the top of Spruce ( all AAA grade) Its a beautiful combination. Its a matter of aesthetics I think...

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Re: Mahogany as an "inferior" tonewood?

Post by stratlanta » Tue Oct 10, 2017 3:01 pm

I have to admit that I once had a similar mental prejudice toward Mahogany guitars but the more I play well built examples of guitars constructed with Mahogany, the more I love them. I currently have an all mahogany steel string dreadnought which is among the best guitars I've ever played.

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Re: Mahogany as an "inferior" tonewood?

Post by Contreras » Tue Oct 10, 2017 8:58 pm

hesson11 wrote:
Thu Apr 27, 2017 9:28 pm
Thank you very much, Alan and Attila. Alan, your clear-headed scientific approach, encyclopedic knowledge and endless curiosity always amaze me. Attila, much to think about there!
-Bob
+1 ... Give it up for Alan - always such interesting and informative posts ... I'm still trying to figure how he finds the time! While the glue sets, maybe :mrgreen:

From my limited personal experience, I have one guitar built with Cuban mahogany, and one with Brazilian ... The Cuban is visually beautiful and sounds sublime ... maybe because it is almost 90 years old!
Put down the bagpipes ...
... and no one gets hurt.

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Re: Mahogany as an "inferior" tonewood?

Post by CathyCate » Tue Oct 10, 2017 10:28 pm

Contreras wrote:
Tue Oct 10, 2017 8:58 pm

... From my limited personal experience, I have one guitar built with Cuban mahogany, and one with Brazilian ... The Cuban is visually beautiful and sounds sublime ... maybe because it is almost 90 years old!
I will leave it to you Contreras to cross reference your new vintage spruce day thread. I am technologically impaired. The bragging rights are yours for certain.
I am amazed! Serious eye candy indeed and in perfect condition. A dream guitar to dream about. Congratulations once more.

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Re: Mahogany as an "inferior" tonewood?

Post by Ramon Amira » Tue Oct 10, 2017 10:33 pm

All this technical knowledge and information is amazing and very interesting. I would point out though that more than a hundred and fifty years ago luthiers were building superb and outstanding guitars that rival and exceed modern day guitars built with the aid of an array of technical devices and information. Intuition and experience may well be every bit as good as technical guidance.

Ramon
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Alan Carruth
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Re: Mahogany as an "inferior" tonewood?

Post by Alan Carruth » Wed Oct 11, 2017 5:53 pm

Ramon Amira wrote:
" Intuition and experience may well be every bit as good as technical guidance. "

Given enough time certainly. Guitar designs go through a process of cultural evolution, which is faster than biological evolution, but works in much the same way (except for being more Lamarkian). Makers try things all the time in an effort to make a 'better' guitar, and every once in a while one of the experiments works out. When it does, everybody copies it (lest they fall behind), and it becomes part of the 'standard' design. People have been making guitars for a very long time, and pretty much everything that was technically possible has been tried (many times). It's hardly surprising that it's difficult to improve on the best traditional designs, even with the use of modern technology.

What modern technology can do is enhance experience. Instead of saying that something sounds louder, we can actually measure and see if it is louder. Sometimes you find that it's not. After a while you get to where you can separate out the stuff that really does work from the stuff people think works but doesn't. That helps you gain some measure of control over what you're doing, and point to possible avenues of improvement.

One thing that I've found in my studies is that the old boys pretty much got it right. In fact, I'd be quite surprised if I found something they did that was categorically 'wrong'. There have been 'scientific' guitar designers who have been so bold as to suggest that the standard designs were 'bad' in some ways, based on some model they've generated. Usually it turns out that they don't understand enough about how the guitar really works: the flaw is in their model, not in the guitar as we know it.

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Re: Mahogany as an "inferior" tonewood?

Post by amade » Sat Oct 14, 2017 3:21 pm

Mairants on Gonzales.jpg
This is what Ivor Mairants had to say about Cuban mahogany as a tonewood, Notice that he (who provided professionals with Fleta, Ramirez and other top luthier guitars) used the words "excellent" and "exceptional" in regard to guitars made from Cuban mahogany.
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DJB

1966 Anselmo Solar Gonzalez (SP/Mahogany)
1970 Jose Ramirez 1a (CD/BR)
1970 Masuru Matano 300 (CD/IR)
1972 Aria AC 40 (CD/IR)
1979 R. E. Bruné Baroque lute
1980 R. E. Bruné Renaissance lute
1990 K. Yairi T-10 (SP/R)

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