(Another) Intonation Question…

And therein lies the issue. How many Luthiers do you think can invest in a CNC machine to slot a fretboard.?
I wonder what Luthiers did before computer operated mchinery became available. No wonder all the old Martins are such crap!!
It's simple.

OK, I should have been clearer. Outsource the slotting. Buy the fretboards in pre slotted from Stewart MacDonald or others. I have a bunch of bruewei ukuleles and they are always accurately fretted even if the nuts and saddle aren't always accurately placed.
 
It’s a bit of a shame that the thread has ended up with folk criticising each other and particularly so when all the voices here intend to be helpful.

CNC fretboards. Well I guess that that is how the big manufacturers do it now and doubtless they have good reasons for doing so (cost/commercial, quality and accuracy come to mind). However there are many traditional alternatives that work quite acceptably and some have done for literally centuries. If I built a Uke then I’d be tempted to buy a (CNC) fretboard for it, if I built more then I’d be tempted to make them myself and see (or rather hear) what I could manage.

CNC is an abbreviation for computer numerical control; prior to computers operating machines humans used to read dials and turn handles to put cutting tools in the desired place - many humans did so with great accuracy too. Perhaps such human machinists made jigs that helped make cheap mass production of fretboards possible before CNC. With good eyesight, a steady hand and perseverance it’s surprising what useful results you can deliver with just a ruler to measure by.

The high tech stuff and precision is all fine and an ideal worthy of aiming for, all good information and a way of working that’s right for some. Personally I’m with JC’s view on things which I perceive to be: keep it simple and aim for functionality.
 
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OK, I should have been clearer. Outsource the slotting. Buy the fretboards in pre slotted from Stewart MacDonald or others. I have a bunch of bruewei ukuleles and they are always accurately fretted even if the nuts and saddle aren't always accurately placed.

The point I am making is that computer generated fretboards are not needed to produce accurately slotted fretboards. Craftsmen have been doing so for hundeds of years and will, by and large, continue. CNC's are not needed for fretboards nor for inlaying, they simply cheapen the craft imho.
 
OK then, I'm a luthier, but I'm still a lousy swimmer.

John Colter.
 
I have no problem with what you say, Bill, except for calling the Rule of Eighteen a "rule of thumb". It is a perfectly valid method of determining the fret positions for a given scale length.

John Colter.
 
I didn't want to really have a fight over the technicalities of intonation.
My view is that if you can accurately fret by hand then keep on doing it and as such placing the nut and saddle accurately shouldn't be too much of a burden.

I think that buying in a machine pre slotted fretboard would be a good way of doing things for many but please don't just assume that the end of the fretboard is exactly where it should be. In the case of a bought in board it should come with specifications so measure from the centre of the 12th fret to the end of the fretboard and double check where it is supposed to be. A 1mm gap from where the nominal scale length falls to the leading edge of the saddle should be right for the saddle as long as the nut is placed correctly.

Again, a lot of the measuring I'm doing and proposing is from the point of view of a repair guy trying to fix intonation on various instruments that they don't absolutely know the specifications for and this is actually a common situation to be in.
 
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Checking in... Original Poster :)

The Journey…. [I’ve been signed out since the US holiday and as such just catching up on posts since 05/24]

To “respond” to a number of the comments that may seem critical as to the lengths and depths of replies and my efforts to apply the suggestions to my questions… I’ll first refresh the point of my original post!

1-Acknowledging that this is a rabbit-hole-inquiry.
2-I have three ‘ukulele, purchased at three price points.
3-For the least expensive I electronically measured the pitch at octave (12th fret) to be very close to a calculated Hz) …. all strings.
4-The most expensive was reasonably close, thought the range of “flatness” string-to-string wasn’t consistent.
5-The mid-priced was considerable flat “when compared with the other two results.”

The detail I provided as part of that original post was to provide some background that I thought would be helpful and cut down on clarifying followup questions.

I was/am seeking advice on a) what causes an instrument to play flat over all strings, b) what remedies are available if a correction is possible OR desirable, and, c) this seems like a very open and knowledgeable forum from which to search for these answers.

I was/still-am willing to apply the various measuring techniques suggested to get the knowledge AND to decide whether I want to do anything, if anything can or should be done.

Any criticism of the responses of those who are guiding me thru (or mis-guiding ! for that matter) is very short sighted. I believe the forum heading is “Tech Support” … from which I expected some level of detailed reply from experienced players, owners, builders, etc. To each of them… sincerest thanks… really.

Please note… I use paragraph breaks ;-)

More discoveries….

While away I found two videos from a quality builder/luthier of whom many of you are familiar. I think he did a nice job of an overview and summary of the matter of intonation. Anyone who has a curiosity like mine will benefit from the combined 12-14 minutes of viewing.

‘Week 45: Intonation Part I’ From MyaMoe Ukulele
https://www.youtube.com/watch?v=PgUgMcnY8N4

‘Week 46: Intonation Part II’. From MyaMoe Ukulele
https://www.youtube.com/watch?v=r6cSZ4XmV0A

Over the next day or two I’ll finish my measuring “assignments” so as to find conclusion to the question for my mid-priced STC.

As a final note… I picked up ANOTHER ‘uke during the break, an Islander MAPG-4-C from HMS. Figured maple ‘laminate’ top, back, & sides. I upgraded to Gotoh tuners (love ‘em) which may have seemed spendthrift for a $165 instrument. But wow, I love the tone, and sustain. Super set-up by HMS. Restrung with Worth Browns. And, yes… I did the same octave pitch measures and it came in similar to the Romero Replica.
 
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I understand that keeping intonation ‘close’ with shorter fretboards difficult. But with consistently flat intonation in this larger range I was hoping for advice on improving the deficit. Where do I start to ‘sharpen’ the notes as the scale increases. (obviously I’m keeping the ‘inferior’ Montecito as-is … wink)

Hi... original poster here.... This is a quote from my original post. Not sure where you're headed with this :) ... but it does get to the original question... what do I do now?

[and to quote a former boss of mine, "Ask him what time it is and he'll tell you how to make a clock...." and even then you don't know what time it is.]
 
I've no doubt this will have been covered by one of the previous replies, but if you need to 'sharpen' a ukulele, you really do need to establish the reason that it is playing flat.

John Colter.
 
On 12th fret, do actually press down the string with a finger (index or middle or ring) or do you play the harmonic to test this? Did you try it also with capo instead of fingers? different ways of playing the note can make a big difference too.
 
Such a deep and probing inquiry. I literally hear you. The is no way to get a stationary fretted instrument in perfect tune and intonation. That's why violins and their family are fretless. They can be played in perfect tune by extremely skilled players but usually aren't. Here's a link to an article about guitar tuning compromise which is applicable to your situation. I hope you find it interesting and helpful.
https://www.reddit.com/r/audioengineering/comments/2oh58e/temperament_and_why_tuning_is_always_a_compromise/
 
On 12th fret, do actually press down the string with a finger (index or middle or ring) or do you play the harmonic to test this? Did you try it also with capo instead of fingers? different ways of playing the note can make a big difference too.

Thanks. I was pretty careful when fretting. After my initial posting I repeated the intonation measures using the tip of a pencil erasure placed as close to the center between fret wires. Outcomes were pretty close to the original. And no, I didn't try a capo.... go idea though. I'm not going to repeat the exercise at this point :)

OP
 
Such a deep and probing inquiry. I literally hear you. The is no way to get a stationary fretted instrument in perfect tune and intonation. That's why violins and their family are fretless. They can be played in perfect tune by extremely skilled players but usually aren't. Here's a link to an article about guitar tuning compromise which is applicable to your situation. I hope you find it interesting and helpful.
https://www.reddit.com/r/audioengineering/comments/2oh58e/temperament_and_why_tuning_is_always_a_compromise/

THAT was a quality posting! Another qualified listen/look at intonations from a practitioner's perspective. He/she's gotta know what there doing to keep their customers happy. Looks like he has issues, too, with all the "experts." Fortunately I'll NEVER be in a sound studio to experience that level of near-perfection. Thanks for sharing that.... definitely worth the look and read.
 
FINAL update :)
I have been introduced to a local luthier with whom I shared the substantive portions of this thread as well as the (seemingly) reams of numbers I measured and recorded. His 'finding' is that the scale of the concert Romero is slightly longer than the 378 in my last set of measurements. He eventually removed the 'factory' compensated saddle and made some adjustments to it. The tonal measurements that were in the 20-25c flat range improved to the 8-12c at the 12th thru 15th frets. My original post lists the original rough measures.

FWIW, I'm quite pleased and honored at the time taken by so many of the forum to push me through the rabbit hole. If you have access to a local luthier, consider yourself very fortunate. However, there's something to be said about taking the journey and learning something(s) new and interesting. Thanks to everyone.

BTW, acquired another uke (with near "perfect" intonation). A Kala Travel concert cutaway, solid spruce top with laminate spalted maple sides and back. Purchase from UkeBug.com a small store in Ohio. Perfect setup, two day free delivery ( ordered on Friday afternoon, he stayed up late to package and ship before going on vacation!). I added Worth browns and a set of GOTOH's. I bring this up only because it's not the only instrument I can play for the next 6 weeks.... Crashed my bike, broke collar bone and ribs! That nice, slender (thinline) body fits nicely under my sling while healing. :)
 
Regarding temperament and the possibility or impossibility of intonating correctly at all frets, there are some tricks a good swimmer can pull off. Fanned frets are getting more common (or at least, less uncommon) on longer scale instruments. Check out this guitar video for a great discussion of the issue and a demonstration of a super-wacky Steinbrenner squiggly-fretted True Temperment guitar:
 
Regarding temperament and the possibility or impossibility of intonating correctly at all frets, there are some tricks a good swimmer can pull off.

Sure :) ... but close examination of the video shows the players' fingernails are not cut to consistent lengths, and he has a small boney protuberance on his forefinger that could affect bridging on the E string. That completely ruins the fret-bound corrections ;-)
 
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