instrument depth

i would like to ask this here among a demanding crowd. there are the standard depths for the various size ukuleles. i would like to hear observations from those who have increased or decreased instrument depth, what happened, what you can do and what you can't.
the very little i can deduce is that depth generates resonance and low and mid overtones which is only a vague idea of what is going on. there's nothing like having done something.

Checking my Kamakas, I notice that the depths range from 2 1/2 to 3 inches (approximate) on the Soprano to the Baritone. Interestingly, the 8 string and the 6 string are at about 3 inches but the Tenor is about 2 7/8ths, even though the bodies are about the same size. My Concert and Pineapple are just slightly deeper than my Soprano. The Ohta San is 2 3/4. So, they do get deeper as the body size increases, but not by much.

yeah. the makers hold to those general figures so religiously that there must be collective experience that they are a sweet spot. ?

You might go to the ukulele site and listen to a side by side comparison of the KoAloha thin body tenor and regular tenor.

I can't really measure my 'ukes at the moment but my small-voiced Harmonia baritone is at least 1/2-inch thinner than my tenors, which are a bit thicker than my concert and sopranos. I think that bari was meant to be electrified.

Highmiles said:

You might go to the ukulele site and listen to a side by side comparison of the KoAloha thin body tenor and regular tenor.

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good suggestion. the thin body koaloha didn't give up any whole lot to the standard tenor. however it did give up a little bit and that bit makes all the difference, the resonance and inner reverb. it's the same with playing trumpet, a several percent improvement magnifies into something much larger as you concentrate your sound. wind and esp. trumpet are a bit different but the small percentage of sweetness thing probably runs across all musical instruments.
the koalohas are radically different in depth with the slimline model. it might be different shaving size down by quarter inches.

The tenor ukes I make measure 2 1/2 at the upper bout and taper to 2 11/16 on the lower bout. Why this is I have no idea. I leave it up to the uke designers that know more than I do. They sound great. Its a mathematical thing I think. Just making the sides higher in order to get more volume is a zero sum deal. The distance the sound travels off the back is inversely proportional to the area of the soundboard. Make the box too deep and it just gets boomy. Make the box too thin and it gets tinny. The sweet spot on a tenor is about 2 1/2 inches or 65 to 70 mm according to my templates. Some famous makers make it a little deeper. I don't know.

chuck in ny said:

i would like to ask this here among a demanding crowd. there are the standard depths for the various size ukuleles. i would like to hear observations from those who have increased or decreased instrument depth, what happened, what you can do and what you can't.
the very little i can deduce is that depth generates resonance and low and mid overtones which is only a vague idea of what is going on. there's nothing like having done something.

Click to expand...

Here is one luthiers take on the thickness.

https://m.youtube.com/watch?v=mUsEtBbftIQ

https://m.youtube.com/watch?v=v8LlnL-EyoM

It would be interesting to hear the differing theories for design from various luthiers.

hammer40 said:

Here is one luthiers take on the thickness.

https://m.youtube.com/watch?v=mUsEtBbftIQ

https://m.youtube.com/watch?v=v8LlnL-EyoM

It would be interesting to hear the differing theories for design from various luthiers.

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thanks. that was great info from tom parse. i'm going to give thin a shot.

I don't care or worry at all about exact depths.

For Tenors, Concerts, Baritones I'm around:

2 1/2" to 2 3/4" for the neck join
3" -3 1/4" for butt end.

Whatever.
If it sounds great and fits in the case, im happy

This is the second Ko'olau built with a different depth.....it sounds really good...maybe the depth does not mean too much?

http://www.theukulelesite.com/ko-olau-cs-spruce-rosewood-slothead-tenor.html

If it sounds great and fits in the case, im happy

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It is a very good idea, before you start experimenting with new dimensions/shapes, to determine if it will fit in a standard case. It's awfully frustrating when it won't.
Miguel

I'm going to try this...

when we look at an object of art there's a few things going on. you have expectation, is it the norm, and you have proportion. in the dreadnought shape the travel uke dimension starts to look like a lady who has lost too much weight.
i am planning a series of instruments in the cigar box shape, sensitively proportioned but a rectangle nonetheless. i suspect this shape will look more natural or cohesive in a thin body.
a high end luthier has reasons to pass this by. proportions and balance mean a lot. marketability means even more for those who eat daily. maybe the slim line has its advantages whereas the normal depth has to have resonance advantages in certain frequencies. there are always trade offs.
i'm going to go with slim. ergonomics was at the top of the list in deciding to build, getting e.g. the neck full as i like things, and a much more comfortable hold is too attractive to pass by. you're going to love it more if it fits you naturally and comfortably. that along with making instruments from hand harvested NE forest hardwoods in the restrained shaker/zen/yankee style. love of wood always gets you a long way.
thanks for participating in the discussion.

chuck in ny said:

i am planning a series of instruments in the cigar box shape, sensitively proportioned but a rectangle nonetheless. i suspect this shape will look more natural or cohesive in a thin body.

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An idea just struck me re: boxy instruments.

Assemble two boxes that nestle into each other with their interiors open and their top and bottom braced. The smaller bottom box may be two inches deep; the top, three inches. Slide the boxes in and out to change the depth / interior space; set screws hold them in place at any desired position. Attach a neck to the top (outer) box and cut an oversize soundhole with a pivoting cover so the opening's size can be altered. Secondary pluggable ports could also be cut in the top.

The result: a boxy-'uke test bed. See what happens with various depths and soundhole sizes, or with foam blocks set into the corners or other locations. The boxes need not be only rectangular. A similar setup could use oval boxes, triangles, whatever. Simple engineering!

This is where we need a real acoustic instrument designer in the Lounge to come in like the voice of God: "The depth of a 12 inch tenor ukulele shall be 2 and 17/32nds of an inch."... I'm with Beau on this one. If it sounds great, whatever... My personal theory? A 2 1/2 inch side looks good with a 2 1/2 inch sound hole. However I think the depth of the box could effect the timbre of the ukulele. I'm just not sure why or how.

Very interesting video of some ukes by Tom Parse. I'm not totally convinced, but it is intriguing. Marketing or real? It is frustrating on the first video that he doesn't strum some A-B comparisons. His main point is that the ukulele is an evolving instrument (agree) and that it is too fat depth-wise (not sure I agree with that). Anyway, I'm headed into the Fred Flintstone Uke School of Lutherie lab to build a "thin-line". I'm thinking cedar would be right since I'm expecting bright. Thinking about 2 inch? Or whatever.

sequoia

tom parse more or less convinced me. i found him credible. he had done blind testing and had a bunch of players who consistently picked the thin instrument. his reference to the violin and mandolin was thought provoking.
i don't find fault in the standard depth instrument far from it. i am however going for ergonomics and thin is too choice to pass up. tom's observation that the sides aren't resonating surfaces and could be lessened made some sense.
wood is some factor here as well. i have hand harvested black ash and will add a supply of white ash and possibly other species the determining factor what falls easily to hand. you would have to be beyond genius level to compute this. perhaps the 1 7/8" body would sound just right using a particular species and not its cousin. not really 'right', just particularly good. fortunately this is the realm of intuition. if a woodworker sleeps on a problem long enough he/she will have some general notion by the time it gets produced.


edit. thought about this and it became a simple matter. i'm going to use a uniform 2 1/4" depth with all sizes.
you have the cigar box shape so that is about what you would expect to see. then, the soprano lower bout at 2 3/8" isn't too much to get your forearm around, so perhaps a tad less, and for comfort little more is needed. this is going to be highly appreciated by tenor and concert players. if you set to build a backpack instrument then you have a different case and it can be slimmer. then at 2 1/4" you have more area for the neck joint than at tom parse's 1 7/8". i'm not averse to building the smaller size and just need a particular reason to do so.
this one is coming down to common sense more than needing intuition.
i'm a country cabinetmaker and not bad as far as i go. those with dedicated skills and experience can experiment and come up with better observations on tonal quality. fifty instruments later i might have some idea.

Built 3 identical ukuleles EXCEPT varied body depths to see any difference in sound...Results?...the deeper the body, the more 'bassy'.....

What the heck is a "real acoustic instrument designer"?

RPA_Ukuleles said:

What the heck is a "real acoustic instrument designer"?

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Loyd Loar

There is certainly a vague sweet spot for depth, body and soundhole dimensions. Tradition as found it in all instruments, but its ok to add or subtract from these proportions a bit without any lost to optimum sound re top vibrational area and air cavity etc.