upper bout vs. lower bout

your thoughts please on this matter. what does the upper bout bring to the table? it seems the lower does the heavy lifting. on that subject, what do you think about the super size trend and making instruments an inch or so wider than usual? if you went in the other direction and made an ukulele narrower, i assume it would not be as resonant.

As a player, whenever I have compared full body instruments to cutaway instruments I always prefer full body instruments for a fuller sound. I know the lower bout is most of it but the upper bout is still adding something.

Anthony

chuck in ny said:

your thoughts please on this matter. what does the upper bout bring to the table? it seems the lower does the heavy lifting. on that subject, what do you think about the super size trend and making instruments an inch or so wider than usual? if you went in the other direction and made an ukulele narrower, i assume it would not be as resonant.

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I actually did some research on this subject and my final conclusion was: Nobody really knows. If you turn to the pointy-headed guys with the graphite dust and the trandsducers and laser measuring devices, pretty much the conclusion is they don't really understand what the upper bout does. Black box. Unknowable. Sorry. If you read about the old masters and what they thought, the same sort of lack of conclusion is evident. Sure we can understand what is coming out of the bridge and lower bout, but what is that upper bout doing. What it is doing is being a part of the whole. But what part? Some Spanish master guitar luthier was asked this question and I think his reply pretty much sums it up: The upper bout? That is where the note she goes to die. What the hell does that mean? The upper bout is where science meets art. I built this "no upper bout" uke as an experiment and the thing sounds great. My conclusion: Less upper bout the better.

I hate to comment on things I'm not sure about, especially when so many like to practice "voodoo science" where these kinds of things are concerned.

However, I thought I read some book on the physics of musical instruments and I thought the upper bout just contributed more of the mid frequencies and the lower contributed more of the lower frequencies with it just being a function of area.

I do remember that most of the higher frequencies come from the top side of the soundboard. The internal cavity acts more or less as an air pump. I think the "Helmholz" effect describes what goes on in and around the sound hole.

I'm not positive regarding the effect of the upper bout but I thought I'd throw all this out there anyway.

Doesn't it provide more surface area for the soundboard, as compared to an ukulele with the same size lower bout but no upper bout? I don't know what the value is of more soundboard surface area (better vibration?) but if there is any benefit to more soundboard surface area, then I imagine that upper bouts would provide it.

I have on of these:



And trust me when I say, it has puh-lenty of resonance. No big butt lower bout, not much of an upper bout at all. But it rings like a bell. They all do. There's just some kind of magic about them.

I don't think it brings a great deal to the party. The soundboard (even on a guitar) is pretty stiff in that area. For one thing you have normally got a couple of large braces either side of the soundhole, on top you have a rather hefty brace in the form of a fretboard.
You can still effect the pitch of a note by pressing hard with your hand on the upper bout, so it's still vibrating, effecting the rest of the soundboard and the tension of the strings.
A test would be to get someone else to play an open string, alternating a hand being placed on and off the upper bout. Not hard enough to alter the pitch but enough to dampen the soundboard in that area. Do it 'blind' and see if you can tell when the player is dampening and when they are not. Try it on all strings. Then swap players, see if the other person can differentiate.

Consitter. That's a Cittern type shape, which I happen to be very fond of. Although I don't do a Uke in that style I have made metal strung Citterns and a 6 string 'guitalele' in a similar style. Not sure about the soundboard patterning but I love the form of these.

Much of the soundboard movement is between the bridge and the end of the guitar and along the edges where it meets the sides but it all moves so a larger surface area moves more air and is louder.

I would doubt (don't know) if the shape of the upper surface of the soundboard matters as much as its area.

Internally there may be different frequencies predominating in the upper bout than the lower bout.

really a brilliant discussion despite the mystification. i guess this is why rick turner cantilevers the fret board to get more juice out of the upper bout. then most don't and it's not a killer. thanks for the replies.

The lower bout is where the only place the top vibrates and 'generates' sound.

The upper bout adds to the pitch and tone according to how much air is in there, ie how big/small it is. The air resonance (the volume of air/space inside a uke) contributes to the tone.

chuck in ny said:

your thoughts please on this matter. what does the upper bout bring to the table? it seems the lower does the heavy lifting. on that subject, what do you think about the super size trend and making instruments an inch or so wider than usual? if you went in the other direction and made an ukulele narrower, i assume it would not be as resonant.

Click to expand...

I can't comment on the ukulele. However, for a guitar, it is there so it doesn't fall on the floor.

John

It depends on bracing pattern somewhat. In the example of Kasha bracing the entire top is more involved, fan bracing with traverse less so.