Tenor

Tenor Scale
This is a scale length of 406mm (16in) to 460mm (18in) and these days usually about 430mm (17in)

The history of where the 17in median length for this scale came from is easy to trace, but where the name came from and why Tenor, are much tougher questions. The 17in Scale length was, like the 15in Concert, a Martin construct, (though I should say here this is also the same sort of scale length as the Rajao, one of the precursor instruments to the Ukulele. However I don't think this had any bearing on the actual origins). At the end of the 'teens William J Smith & Co., a major distributor of Martin products at the time, asked Martin to produce a kind of Chordophone based around the Colombian Tiple, (exactly what they asked for and what Martin based the subsequent instrument on I'm not sure? The Colombian Tiple is a bit bigger, about a 22in scale, tuned D~G~B~E and has 12 strings in 4 courses of 3). As a result of this request, in 1919 Martin produced a 17in scale 10 string Chordophone with 4 courses the outer courses being 2 strings and the inner being 3. As it was steel strung, the tuning for the new instrument was, (per course), A~D~F#~B The same as a Ukulele of the time so the new instrument became the Tiple Ukulele. For all of the tuning "fun" involved with it, the instrument proved popular, Martin continued production of it and a lot of the other big Mainland makers in Chicago and New York started making them. 9 years later in 1928 Martin used this body size and scale length to start production of a new, large 4 string Ukulele with gut strings, tuned g~C~E~A, and they called this their Tenor, (This may have been to counter Gibsons new TU Ukulele, also this size; or Gibson may have copied Martin? Martins record keeping at the time was very exact, Gibsons wasn't). Though the two most prestige US manufacturers were making them, at the time the scale length didn't catch on that much, none of the other big manufacturers introduced them, Possibly because they were sticking with the Standard Approved smaller sized definition of Tenor?) and only a few of the more specialist Ukulele firms had a go before WWII. Post WWII it was only really Soprano and Baritone scales that regained popularity in the US. However both Martin and Gibson continued production of their Tenors throughout this period and because of this 17in became the defacto Tenor scale length. With the decline in Ukulele popularity again in the late 1960's even Martin and Gibson gave up production of all Ukuleles, leaving only Kamaka in Hawaii as a serious manufacturer; but by this time Kamaka had taken all of the Martin scale lengths, (before the war they only made Sopranos), as their own and they were producing 17in Tenors as part of their catalogue. With the Ukulele rising in popularity again post millennium, it was the old Martins, (Gibsons to a lesser extent), and the output of Kamaka that gave the basic definitions to what scale lengths should be, and the larger 17in scale proved popular with Guitarists moving down to the Ukulele, thus bringing it to far more prominence now that it ever had historically.

The origins of, and reasons behind the name itself are, as I have said, a bit more of a mystery. I am not aware of it appearing in any makers catalogue before 1926 and the National Association of Musical Instrument and Accessories Manufacturers proclamation of "official" Standard Approved scale definitions and string lengths so it may be that they came up with it? But why, (and this goes for whoever came up with it), when the other two sizes were called Standard and Concert, was the switch made to a musical term? Possibly because the prevalent Ukulele tuning for the smaller instruments at the time was a~D~F#~B and this larger instrument always had a lower g~C~E~A tuning? Whatever it was this name, and the later introduction of the Baritone, led to the Standard becoming a Soprano, (but the Concert never became an Alto?). That is my guess and if it was for another reason I don't know it.

The standard tuning for a Tenor is g~C~E~A and with Nylon/Gut strings. It never goes higher, though there are some people who do like to go lower, even down to e~A~D#~F#; This is not particularly common though. What is quite common as a tuning alternative though is to not have re entrant tuning and have the G an octave lower as the lowest note, (this is called Low G tuning and does require a different, thicker or heavier string for the G)'. This moves the Ukulele away from its traditional sound and the "wall of sound" style of playing but gives a greater range of tone particularly for single string solo playing or finger picking. It has also led to the development of a 5 string Ukulele where the G has become a two string course with both a high and low G to try and give the best of both worlds. The tuning can be complicated further by the use of strings designed for a Baritone D~G~B~E tuning, (or re entrant d~G~B~E) but this takes the instrument into the Jumbo Tenor / Mini Baritone arena which can be a quagmire of understanding as different people use different terms to describe the same thing! This Wiki's definition is:- If the ukulele has a scale length of 460mm or less but is tuned DGBE, (re entrant or not), it is a Mini Baritone. if it has a scale length of 461mm or more but is tuned GCEA, (re entrant or not), it is a Jumbo Tenor; but this has no true authority.

A final note on the build of Tenors; it is more common now to see the neck of a Tenor join the body at the 14th fret, (higher that the 14th and the body size usually starts to shrink making in a Super Concert), but they started out joining at the 12th and some people still make them that way.