The modern era starts in 1928 when Adolphe Sax jr. sells out to Selmer. Selmer then builds a series of instruments with double serial numbers, assembling unfinished A.E. Sax instruments. An era of diversity and experimenting gradually comes to an end.
Tradition reigns in instrument making: the unfinished instruments that were still in his workshop when A. E. Sax sold it to Selmer have turned out to be pivotal for their later production. Selmer continues to use A.E. Sax parts until the balanced action series. A Selmer Mark6 differs acoustically still little from these Sax jr./Selmer transitional instruments. They thus mark the beginning of Selmer as an important saxophone brand and as an influence in general. This influence stretches as far as the far east: modern day Yamahas are acoustically still very, very close to these Sax jr./Selmers, although the japanese bring the work to an unprecedented technical perfection: never before saxophones were thus round, tone holes thus secure up to the tenth of a millimetre. But the influence of the Sax jr./Selmer transitional instruments was not directly felt in America. Here we see that the Buescher and Conn instruments are fairly close to one another until well after WW2. This american tradition retains, more than the european way, a couple of older characteristics, such as a bore that is a tad wider than contemporary french instruments and tone holes that are probably a little bit smaller. As far as mechanisms are concerned, the americans also tend to be more conservative.
Another characteristic of the modern period is the upscaling of production and the arrival on the scene of the asians, which forces the older and smaller brands to close. As a result peculiar traditions vanish with the disappearance of makes like SML (multiple stepped cone in the soprano), Toneking (contracted cone in the soprano), Martin (multiple stepped and wide cone in the 'the Martin' alto) or Buescher (400-tenor with a narrow cone that somehow reflects the original design of the Ad. Sax tenor). Mainstream becomes stronger.
You would expect the instruments (SATB) of a generation per instrument maker to have the same characteristics, but that's not true. The four Bueschers or the four Selmers presented on the previous page each have their specific traits, but these traits are more rooted in a tradition per instrument size than per instrument maker. For reference, see also the pages on bore profiles in the MEASUREments–section.
SS Sopranos show a wild variety of cones. Buescher build in the early 20th century a curved soprano that has a wide cone which is, you might say, parabolic in shape along with a straight soprano with a contracted cone (not documented here). These contracted cones were at some time in history mostly to be found in sopranos (Buescher straight C-soprano, Schenkelaars, Toneking, even a Selmer Mark6) and there were multiple–stepped cones (Selmer 22, Martin Handcraft, SML), but the general tendency is that cones get straighter through time. Soprano bells spring fairly directly from the main tube. And only in sopranos we find a curious little piece of narrow cylindrical tubing at the entrance of the neck. I do not know where this feature stems from, but a 1924 Selmer modèle 22 was the oldest instrument I came across to have it; a 1927 Martin Handcraft the youngest not to have it. So that's roughly the period in which this feature has become a part of soprano design. You don't find it in the early instruments (and certainly not in Ad. Sax's), but all modern ones have it, although you can easily do without (provided you take the necessary precautions).
Noteworthy is that curved sopranos once used to have a bore that is wider than the straight models. These instruments were not built on the basis of identical tube parts, as is illustrated by the difference between the curved and straight Buescher and Martin sopranos from the 20s.
Noteworthy too is that the truncation of sopranos has drastically diminished. The original soprano had keys up to high Eb and truncation matched that. When the tessitura was enlarged to high F, truncation length was not immediately diminished, but followed step by step. When the high F# was finally added, the neck was lengthened with almost two centimetres. For an example, take a look at the picture in the «CONCERT PITCH» page or study closely the difference between the Selmer SA-III and the other sopranos in the MEASUREments-section.
AS Altos tend to have fairly straight cones, sometimes even including the bottom bow, although bottom bows can also show an s–shaped twist and – mainly in american design – some contraction relative to the main cone. Bells, other than in the sopranos, are preceded by a piece of tubing of a wider conicity than the main cone. The necks have some kind of a curved profile, making a step downward relative to the main conicity. Yet a curious tendency is recently to make necks wider and wider, which helps to create a sonority that might be desirable to some, but which causes instruments to be annoyingly sharp in the upper half of the second register. Also keys tend to rise higher and higher, which brightens up sound, but also makes intonation more awkward.
TS The tenor is more or less shaped like the alto, but the main difference is the frequent occurrence of the sword profile: a reduction of conicity down the main straight tube in the bottom bow and first part of tubing preceding the bell. Is it a recollection of the parabolic cone? Fact is that this difference between alto and tenor profiles is as old as the post-1866 saxophone design, the tenors retaining a pre-1866 trait which the altos have lost. A tenor with a really straight cone is a rarity (an 1932 Couesnon comes closest – as yet not documented in this website) while most instruments show a contraction that is at least as evident as the second generation Ad. Sax tenor had. And of course, the modern tenor is as wide a Adolphe Sax made it in 1866: the original design was only followed by the Gautrot-Marquet mentioned before and, much later and somewhat more remotely, by the Buescher 400, as far as I know of.
BS Baritones have two main different types of profile, depending on whether they go down to low-Bb or to low-A. The low-Bb–instruments have, like the altos, a piece of tubing of a wide conicity preceding the bell, but the low-A ones, on the contrary, have a straight or even contracting profile, with the bell springing almost directly from the main cone. However, most intricacies in the baritone profile we meet in the upper end. The short and relatively wide bows there produce intonation troubles (mostly in the lower end of the second register) which had to be sorted out through time. Especially the upper bow acts acoustically as if shorter and wider than it is and this we have to keep in mind when studying baritone profiles. It is also obvious that perturbations in the cone are smallest in the biggest instrument, which make baritone profiles look like relatively straight cones.
Baritones are the only member of the family that go down more or less successfully to low-A. The rare Mark6 alto to low-A which Selmer once made was only matched by an even rarer Couesnon and Selmer themselves never made a follow-up. The Selmer alto is reported to be acoustically distant and unwilling. The baritone, with its more slender cone, works better. Yet, a baritone to low-A still doesn't feel as wide open as the baritone to low-Bb. Here again, I would like to refer to my own struggles with acoustical stability in building an alto saxophone with a parabolic bore (see «A TRIBUTE TO SAX, THE MAKING OF THE BORE»).