Why does lowering string action (without buzzing) cause decreased volume?

baconsalad

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If the string is not buzzing, in my opinion the lower the better, but i'm told advanced players who don't want to sacrifice volume want higher action. Also was told my Kamaka is sketchy in it's lowness. What is the physics behind higher strings = more volume (discounting buzzing)
 
My experience as a hobby builder and repairer has demonstrated that lowering the action does, indeed, reduce volume. It seems to me that it results from reduced leverage. The pull of the strings is transmitted into the soundboard as a twisting moment (if that is the correct term) causing tension in the top. Lowering the saddle will reduce the leverage, causing less tension.

As with many systems it is a matter of achieving an acceptable compromise.
 
There are a lot of factors involved ..if you require a low action without lowering the saddle , then alter the neck angle , or use a thicker fretboard.
 
Volume is related to the height of the saddle above the soundboard (up to a point - excessive height can over drive the soundboard and lead to structural failure!). The optimum seems to be around 1/2 inch/12mm.

If you lower the action, you lower the height above the soundboard - thus potentially lower volume. As Timbuck says, you can restore the height by changing the neck angle or fitting a tapered/thicker fretboard (expensive!), or if you're building it, design for the desired low action.

However, there is another factor, playing style. Low action means you can't hit the strings as hard without buzzing. So heavy strummers may have to play more lightly and thus get less volume, even if height above soundboard is fine. Delicate players might not notice any change in volume unless the saddle needs to come down a long way.

But if the height above the soundboard is, say, only 1/4 inch/6mm then that uke will be quieter than it could be.
 
Really interesting post, thanks.

One other thing are the strings : when i started playing uke, i used aquila on a ohana uke's. I changed them and that changed a lot the sound volume and moreover, the quality of the sound volume.

To my mind, don't forgive that ukulele are not guitar so it's not the same sound volume.
Like profChris saids, it's also (a lot) a "problem" according to playing style of the player :)

Ps : I speak only about soprano uke, i suppose that is not the same thing concerning barytone.
 
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As Prof mentioned the main factor is really playing style. If low action sounds good for the way you play then that's great. I have nice old KoAloha and for years I didn't think it lived up to its potential and sometimes I even knocked the fretboard as I am a vigorous player. I finally decided to ask a friend to cut a new ebony saddle to raise the action and now she really sings.
 
It seems to me that it results from reduced leverage. The pull of the strings is transmitted into the soundboard as a twisting moment (if that is the correct term) causing tension in the top. Lowering the saddle will reduce the leverage, causing less tension.

As with many systems it is a matter of achieving an acceptable compromise.

Lowering the action can indeed lower the apparent volume of an ukulele. I'll admit I was always a bit puzzled by this phenomenon, but I think John has hit it on head: It is a leverage issue. So compromise is in order, high enough to give good volume and yet low enough to give good playability so it is somewhere in between. And of course it depends on the players style.
 
My experience as a hobby builder and repairer has demonstrated that lowering the action does, indeed, reduce volume. It seems to me that it results from reduced leverage. The pull of the strings is transmitted into the soundboard as a twisting moment (if that is the correct term) causing tension in the top. Lowering the saddle will reduce the leverage, causing less tension.

As with many systems it is a matter of achieving an acceptable compromise.
This makes excellent sense.

My question is whether this happens whether you lower the action at the nut or the bridge?
 
I think skill level makes a big difference, too. One friend of mine with smaller hands had a luthier lower her string action when she was a beginner and she really liked that for easy strumming. As her skill level improved, especially with legato techniques like hammer-ons and pull-offs, she found that those techniques were much easier to perform on an ukulele with higher action and now she rarely plays the lower-action ukulele.
 
This makes excellent sense.

My question is whether this happens whether you lower the action at the nut or the bridge?
I don't believe lowering the action at the nut will have any effect on the volume. Ideally, one should set the string height at the saddle, and when that is satisfactory, adjust the height of the nut grooves.
 
Actually I did drastically lower the action at the nut one time and it did indeed noticeably lower the volume.
Does it have much effect if it is slight?
 
I came across this page recently. I don't think it answers this question, but it offers some physics about how strings work for those who are interested in looking at more technical discussion that does not go as far as the equations and formulae.
Thanks for that link! I find the physics stuff particularly interesting.
 
I don't believe lowering the action at the nut will have any effect on the volume. Ideally, one should set the string height at the saddle, and when that is satisfactory, adjust the height of the nut grooves.
I agree with John's first point, but I prefer to adjust the nut first and only then the saddle. Our different ways works for us, so we'll fight it out next time we have a beer until we agree it doesn't matter to us!

However, if you don't know what action at the 12th you want (which John and I do), it might be worth adjusting the nut first and then playing the uke. You might find that you are happy with the current action if it plays better on the lower frets.
 
when the saddle height is lowered the break angle changes, the break angle determines the downward force on the nut and amount of energy tranmitted to the top, the lower the break angle the less force is applied to the nut, the less energy transmitted to the uke top. Depending on how your strings are attached (through the top) the break angle may be able to be adjusted. Slots are cut in the bridge to allow the string to exit through the top at more of an angle. here is a photo from Beau Hannams Insta gram site showing the slots I mean. https://hazeguitars.com/blog/acoustic-guitar-tone-and-string-break-angle a better explaination.
 

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Break angle changes slightly. But there must be a larger effect from the lesser lever force from the shorter saddle length.
 
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