Good intonation - how hard to achieve?

Many cheap ukes have horrible intonation. This makes me wonder:

How hard is it to construct a uke with proper intonation? I thought that spacing the frets correctly and compensating the bridge a few millimeters should do it. What else is there to it? Am I missing something?

String choice is a consideration. Different brands and types will have slightly different intonation requirements. As well as the action and playing style of the individual. It shouldn't be too difficult to get it close for a broad range circumstances though.

When it is close, then just play the thing and enjoy.

I dont know who wrote this, But I have been saving it just in case someone should ask this question.
A nice article on intonation.

Intonation

Intonation, as taken from the definition of Wikipedia, states: “Intonation, in music, is a musician’s realization of pitch accuracy, or the pitch accuracy of a musical instrument.” Having what is known as “bad intonation” means that the musician is playing or singing out of tune. Intonation can also refer to tuning.

Strings

When it comes to stringed instruments, intonation matters a lot more than with other musical instruments. Since majority of stringed instruments are unfretted, the note can easily go out of tune in the event that a finger is too high or too low, even if it is less than an inch. In order to have good intonation, a musician needs to have years of practice and experience, which makes this the most difficult part of mastering a stringed instrument.



Ukulele Intonation

There are some individuals, more commonly guitar players, who often ask me if there is a ukulele which has superb intonation but costs little, I always tell them the same thing over and over again: “Forget it…”

Despite the majority of ukulele fretboards manufactured today being cut precisely by computer-guided laser cutters, issues sometimes exist in relation to the free string configuration of the ukulele, which is extremely short, and makes perfect intonation quite hard to attain. Also, ukulele strings which were made from plastic materials like nylon are not very precisely constructed as compared to their steel counterparts – those which are usually installed on banjos, mandolins and the ever popular guitar. Strings made of plastic tend to expand and eventually become flat, making them quite hard to use during the initial stages of use. And if that’s not enough, getting the right intonation greatly depends on the skills and experience of the musician. Intonation will also change in relation to the key played.

Ukuleles have long been known as the instrument of “innocent merriment”, period. They provide hours of fun and enjoyment with every use, although they can’t be considered as acoustic physics laboratories having small sound chambers.

With guitars, most people will usually invest a lot of money making modifications in order to have better intonation, and the ukulele not much that different. Even if the ukulele you are looking at right now is said to have the “prefect intonation”, chances are there is something fishy about it.

If its the intonation of your ukulele that is giving you headaches, it may be a good idea to purchase strings of better quality such as well-known brands Worth and Aquila. You may be surprised on the really big difference this change will give.

Intonation can also be achieved based on how relevant the note played is to the pitch as the musician moves up the fingerboard. In order to check the set-up of your ukulele, the 12th fret needs to sound exactly the same when played on an open string at a higher octave. For example, open A string first course 440Hz, 12th fret 880Hz). Playing a 12th fret harmonic and comparing it with a fretted 12 fret note is also a good way of checking your ukulele. A good instrument will always be able hit each note played exactly to the required frequency. Example is G=392 Hz, C=261.6 Hz, E=329.6 Hz, etc.

When constructing a good instrument, intonation is always an integral part of its overall quality. Playability is also another important factor considered by musicians. How do we actually acquire that much needed intonation? Most people will tell you that it is just as simple as making the measurement from the 12th fret doubled, but the truth is, it just does not work. Always keep in mind that the instrument you are using contracts and expand, and that wood also breathes. The playing style of a musician can greatly influence the intonation of a instrument – someone who strums hard and bends the strings too much when playing the instrument makes more of a noise rather than music. On the other hand, a good musician will do the exact opposite and you feel like the instrument and the musician playing as one.

I learned something new this weekend. there is more to it than the length from the nut to the 12th fret and from the 12th to the saddle. as we all know, the easy way to check intonation is to tune the string and hold down on the 12th fret and see how far it is off, but there is a little more. It never occured to me that the nut can effect the first few notes severly. if it is too high it will make the string sharp in the first few frets. it can be overcome by not pressing down all the way to the fretboard, or lowering the nut (Somewhat risky on cheaper ukes)
So far most cheap ukes are not all that good, but good enough to get by.

It is frustrating when $400 and up ukes don't have good intonation. I would never consider this the cheap end of the scale yet frequently the intonation is not a whole lot better than ukes costing one tenth their price.

You asked what beyond proper fret spacing and compensation at the bridge can affect intonation. Understand that a vibrating string vibrates at a specific frequency depending on its length, diameter, composition, and tension. Anything which affects these parameters affects intonation. So to give a partial list of other things which can affect intonation: height of the nut, height of the saddle, and neck angle (because they affect the height of the strings and thus the amount they must be stretched to reach the frets) flatness of the neck, evenness of the height of the frets, shape of the top of the frets, proper set of the frets in their slots(these all affect the actual contact point of the string relative to where the slots were cut) String material, string diameter(affecting compensation needed), string quality (especially as it relates to strings stretching equally along their whole length) Obviously a string which stretches more easily at on end than the other will not give good intonation. How hard the player presses down on the strings and how close to a fret they push down, whether they tend to push it a little sideways, how hard they pluck or strum, etc. all affect tension. What plays in tune for me might be way off for you. A few other things which can affect intonation are the quality of the nut slots (affecting how strings stretch) humidity(which affects the overall dimensions of the instrument and relative position of the top) and the temperature. After saying all of this, perfect intonation is impossible - but good intonation should be a quality of any instrument built with reasonable care. I like Allen's advice. Get it close and then enjoy playing it.

Hi! olgoat52,
so, what are the ukes that you are referring to?

Thanks guys, I will focus on good intonation as recommended.