How much do you think back / side wood species contribute to tone?

What percentage do you think uke back/sides contribute to tone compared top wood?

I think about 10% back&sides / 90% top.

I base this on that my sides are inert and my backs stiff (they are 0.080") and that said backs are 99.9% of the time resting against someones chest while being played which ceases any vibration/tonal contribution, rendering backs as reflectors of top vibrations only.

If this is even vaguely accurate, are our decisions re back/sides purely aesthetical- ie we like figured brownish coloured wood rather then dark non descript wood?

My last public thought for 2014

If it could be measured scientifically I would bet that back and sides contribution is 0%, that's right absolutely nothing. I know people will pipe up with the qualities of rosewood vs mahogany vs maple etc. But I think its purely psychological.

I play woodwinds and you will find extensive discussion about wood affecting the tone of clarinets. Most clarinetists will tell you that a wood clarinet is inherently superior to a plastic one which is better than a metal one. I read an entire book about the acoustics of clarinets and there has been extensive scientific testing done. There is absolutely no, zero, nothing, nada, measurable difference in sound based on the material used. What does matter is that wood clarinets are made by hollowing out the wood while plastic clarinets are made on a mold. If you smooth the bore of a plastic clarinet with the same precision as is used on the wood ones then they are every bit as good. In fact Buffet makes a green line R13 that is a plastic clarinet with wood thrown into the mixture and I don't think anyone can tell the difference from their wood clarinets. In the 40s a company called Grafton made plastic saxophones that were superb. During World War II some companies made professional quality metal clarinets.

Since the back and sides are stable and the sound comes from the chamber and strings and the top I don't really see how the wood on the back and sides can be in any way relevant.
I know different ukes sound different but there are way to many variables in most comparisons to say that the wood in the back and sides is the difference. So I agree with Beau except that i think the back and sides contribute even less than he surmises.

None - the back acts a a reflector so I think shape is probably the important factor here. L also think that because volume is required over anything else with these instruments that expectation tends to colour our judgement of the other important factors - tone and sustain.

Pete Howlett said:

None - the back acts a a reflector so I think shape is probably the important factor here. I also think that because volume is required over anything else with these instruments that expectation tends to colour our judgement of the other important factors - tone and sustain.

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I would prefer an instrument with a full spectrum of tone over a loud instrument-
ie, when I listen to a uke/guitar record/cd, i don't know if that instrument was loud or soft acoustically, but i can tell if its tone is full or dull. Loudness usually translates somewhat to tone though, due to the top (presumably) vibrating more etc

Beau Hannam Ukuleles said:

I base this on that my sides are inert and my backs stiff (they are 0.080") and that said backs are 99.9% of the time resting against someones chest while being played which ceases any vibration/tonal contribution, rendering backs as reflectors of top vibrations only.

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Yeah, probably very little due to the way ukes are held. But what about adding an internal resonating plate? Called a "double back" by some guitar builders. Then it can make a big difference in tone, just as the back of a guitar can. Hard to put numbers to it since it's really a matter of personal preference whether the live back tone is better at all. But I definitely prefer it.

They can contribute or subtract quit a lot when you go to the extremes. The thick redwood or cedar back and sides of a cigar box ukulele even with a lightly braced top will tend to have a very mellow soft tone. Much more so than if the box was made of thin rosewood. Best guess 15 percent at the extremes.

Its been quite a few years now since I wrote "The Heretic's Guide to Tonewoods", suggesting that the back and sides of an instrument don't make much of a contribution to the sound/tone. At the time, the online community would have put my health in serious jeopardy if they had known where to find me. But the last time that article was brought up on this forum the response was "He's preaching to the choir." My, how times have changed.

The question is does the back and sides species contribute to tone......pretty much none in my experience. You pick them for the color, grain, workability, cost, source, sustainability etc. But as for tone.....nope.

When it comes to how you use them then yes. Shape of the back. How stiff it is, as well as side stiffness. Then yes, that is were you can affect the tone and volume.

If the back and sides contribute so little then why does the players' tip of holding the uke away from your body make so much of a difference? Keep your wrist off the top while we are at it, use a strap if it helps.

If the back and sides are primarily a reflector for the sound waves from the sound board, is there a better material than wood for back and sides? (aluminum, graphite fiber composites, ABS, polycarbonate, bamboo, ? ) I'm just thinking out loud.

Doc_J said:

If the back and sides are primarily a reflector for the sound waves from the sound board, is there a better material than wood for back and sides? (aluminum, graphite fiber composites, ABS, polycarbonate, bamboo, ? ) I'm just thinking out loud.

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We don't know that yet. But for now you can have a wonderful uke made from a lovely set of wood. I don't know what the future will bring, but from an aesthetic point of view I can't imagine it getting better. Satisfaction is such an abstract thing. "Better" is an abstract concept, too. So is "sound" and "tone". I've only known a couple of people who could pull extraordinary music from a given instrument and I don't know how they did it. The rest of us will have to muddle along making musical noise as best we can. So would you rather have a TIG welded metal instrument in your hands, or a wooden thing that makes you contemplate the benevolence of God? You choose, I've already made up my mind.

Titchtheclown said:

If the back and sides contribute so little then why does the players' tip of holding the uke away from your body make so much of a difference? Keep your wrist off the top while we are at it, use a strap if it helps.

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Holding an instrument off the body certainly gives more response as doing so allows the back to wobble. While my primary question included that the back was 99.9% held against the body, we are talking about species affecting tone, not back vibration however even with the back held off the body, I think the results would be similar, ie very very little tone colourization from the back species.

At one point in time, I had a Quilted Maple/Spruce right next to a Curly Maple/Spruce. While they did not have that "broken-in" sound like my current slivers at the time, it "seemed" the Curly was more focused, while the Quilted was more harmonic, for lack of a better term. Basically, you could tell the difference between two, but ONLY when they were right next to each other.

It was then that I described the relationship between the top and back like a marriage - the top being the husband, and the back being the wife; one brings power, the other adds finesse. In reality, that would make it 90% back/10% top (for those that are married).

What does this prove? Nothing. Its only 1 data point so no trend is being set. However, since most of my instruments are Spruce topped, I have a somewhat relative grasp of what the back and sides are going to do. Of course, the Quilted was flat, and the Curly was quartered, which probably had more to do with the difference than the type of figure.

I'll dare say that I think most of my instruments sound alike, regardless of the back and sides. I'll venture to say those that have recorded my instruments would disagree. Then again, this may have more to do with string choice, rather than wood selection.

Titchtheclown said:

If the back and sides contribute so little then why does the players' tip of holding the uke away from your body make so much of a difference? Keep your wrist off the top while we are at it, use a strap if it helps.

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No one said that the back and sides don't contribute anything to the tone. It was the SPECIES that doesn't.

If you make a back light and responsive, then there is a huge difference in the sound, tone and volume you get when the instrument is either held against your belly, or not. But that the said species is irrelevant. Just as if you build the back and sides like the proverbial brick out house. It becomes a reflective back and it doesn't matter what they are made of, and for that matter if you hold the instrument against your tummy or not.

On my recent builds I have made the backs thicker but with only 2 braces - a wide low one in the lower bout (Martin guitar style) with a high thinner one at the waist. The taper is still 10mm and the curvature, a 12' sphere. I'm getting more projection (I think) from this slight modification. I am also adding a 'V' brace to the Englemann or Alpine spruce fronts at the neck block end where I was getting 'pull' and now I have a greater focus in the sound. However, regardless of the specie of wood I use for the back and sides - in my case rosewood - Santos and Indian, makore, walnut - English and Claro, English cherry, True mahogany and myrtle, the overall 'sound' remains very much the same. I therefore conclude that most bespoke builders have 'their' sound which they put into their instruments and clients tend to buy that rather than one that sounds like a vintage Martin, Gibson or Kamaka. Most noticeable is the number of students who have completed tenors on my courses who when they string up their piece remark, "It sounds like a Howlett!" Well it would wouldn't it? Check out this video at 1.50 to see what I mean.



and then this one recorded in a slightly different area of the workshop but a different combo still pretty much the same sound to my ears...
go here to hear.

Allen said:

No one said that the back and sides don't contribute anything to the tone. It was the SPECIES that doesn't.

If you make a back light and responsive, then there is a huge difference in the sound, tone and volume you get when the instrument is either held against your belly, or not. But that the said species is irrelevant. Just as if you build the back and sides like the proverbial brick out house. It becomes a reflective back and it doesn't matter what they are made of, and for that matter if you hold the instrument against your tummy or not.

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This isn't to argue your point, just to try and understand it. Wouldn't the hardness of the different species make the difference then? How well it can resonate or reflect back the sound. Doesn't that add a color to the sound? Or would that just pertain to the volume or sustain of the instrument?

dang, I gotta stop paying a premium for special woods!

If the back acts as a reflector, it seems to me that some species would be better at this than others. Imagine a back made of hard and shiny ebony, versus one made of soft and spongy cork. I'm guessing that all other things being equal, the ebony would reflect much better.

However, the reflective properties of commonly used wood species for backs are not likely to be nearly as different as that between ebony and cork, so the difference might in practice be negligible.

Pete Howlett said:

On my recent builds I have made the backs thicker but with only 2 braces - a wide low one in the lower bout (Martin guitar style) with a high thinner one at the waist. The taper is still 10mm and the curvature, a 12' sphere. I'm getting more projection (I think) from this slight modification. I am also adding a 'V' brace to the Englemann or Alpine spruce fronts at the neck block end where I was getting 'pull' and now I have a greater focus in the sound. However, regardless of the specie of wood I use for the back and sides - in my case rosewood - Santos and Indian, makore, walnut - English and Claro, English cherry, True mahogany and myrtle, the overall 'sound' remains very much the same. I therefore conclude that most bespoke builders have 'their' sound which they put into their instruments and clients tend to buy that rather than one that sounds like a vintage Martin, Gibson or Kamaka....

Click to expand...

IM thinking of going to 2 back braces (mostly because that 3rd brace interferes with my label placement, but also to loosen the back) and trying a 10 foot radiused back (mostly because a 15 foot looks flat on a uke- 15 foot has a nice curve on a guitar though). I was thinking that perhaps the angle of the back in relation to the top and sound hole plays a part. ie- if sound radiates off the top straight down to the back and if the back (as a dish) is angled to focus those vibrations towards the sound hole- this might promote volume. not sure. Thinking of some renaissance guitars the backs are pretty extreme

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Perhaps it is better for the sound to bounce around a bit?? I dont know. Michael P. Nalysnyk might know more????

Dougf said:

If the back acts as a reflector, it seems to me that some species would be better at this than others. Imagine a back made of hard and shiny ebony, versus one made of soft and spongy cork. I'm guessing that all other things being equal, the ebony would reflect much better.

However, the reflective properties of commonly used wood species for backs are not likely to be nearly as different as that between ebony and cork, so the difference might in practice be negligible.

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Yer- i think Mahogany and ebony would share similar reflection properties when sanded to 220 and shellaced.

It's not possible to measure this scientifically and come up with cold and hard numbers. Why? Tone is predominantly a subjective parameter. Our ears and preferences are as varied as the choices we have for tonewoods. A large number of studies have been done already on violins and guitars. It has been proven that the species of back and, to a lesser extent, side woods DO color the spectral analysis of the sound generated by a given instrument. But, how an individual's EARS interpret that difference is unquantifiable. Even the SAME person with the SAME ears on a DIFFERENT day will produce a different result.