Important dimensions missing; max height of neck above the stop surface of the tenon ring and overall length from the front face of the tenon to the player end of the neck. This is the main way we differentiate among the various Selmer tenor neck styles. The MK 7 was the first with the 'high-arch' neck which extended into the SA80 and series II. The late MK VI design was brought back with the Series III. As you can see, the various styles have a very similar water volume, which is simply because in order for it to be a Bb tenor, this is what is required.

 

I'll add those missing dimensions. One thing that I can certainly say is that the dimension of the octave tonehole makes a big difference in the upper register. The original 3mm opening made high E, F, and F# incredibly sharp.

 

Other factors:
- The length of the octave vent hole.
- The inside diameter of the bottom end of the octave vent and whether that hole is cylindrical, a straight taper, or maybe some other odd shape (as in oboe)
- One needs to specify whether the (large end) tenon opening is ID or OD.
- The taper. This is critical. It will depend on:
- The ID of the bore before changing to tenon. The tenon is cylindrical and not necessarily matching the bore it is soldered to.
- The overall length down the centre of the bore (excluding the tenon).
- The small opening which you have provided.
You provide volume, but that is a combination of length and taper and bore parameters.
- Note that some tenons have a tapered bore.
- Metal thickness may be seen as a valid parameter by some people:
The weight is not really an adequate indication of the metal thickness, because it includes the braces, the key and its mounting, and soldered rings.
And the thickness of the wall of the tenon may well be different from that of the amin tube.
The main tube thickness is not so easy to measure, and may vary along the length.
- The internal finish.

 

Gordon, you hit on a few things that I was thinking about, and added a ton of others. In this case, the reason why weight isn't that relevant is due to several factors of how each neck is assembled. Silver plate is naturally heavier than lacquer, but the SA80 neck has a brass badge that the other two do not, thus making it the heaviest.

I've been giving the taper some thought, and am under the assumption that it's actually more important than the arch itself. I'm assuming this based upon a terribly pulled down neck I've recently come across. It had a very creative arch, and some creases (yikes) but oddly played like you would expect. Middle E was stuffy, and the playing angle was.... interesting. Of course, the internal bore was altered here, so it's still not a fair test.

It's been awhile since I've used any type of geometry like this, but I'm assuming that I can calculate the taper based upon the sizes of the openings of both ends. All three necks are smoothly constructed in the bore, removing any other variables that newer Selmers brought to the table.

 

The openings at the end, namely the one at the big end, is not necessarily indicative of the ID of the large end of the tube without the tenon.
Furthermore, there will be some odd effects to the effective taper when the bore goes around a bend. This is particularly evident at the bow end of a sax, and the way dropping a cork or similar in a sax dcan overcome "motorboating".
Who knows, an astute manufacturer may use a mandrel or whatever to make a taper that varies a little along its length.

 

See, I'm trying to figure out which of these attributes are actually noticable to a player, as one's soft palette can compensate for quite a lot. What I can't seem to comp for are badly sized tone holes, which going off of basic flute manufacturing theory, seems to make sense. The Chinese neck is useable now, but that extra millimeter that I cut off impacts octave response. I should actually fill the hole, and drill a 2mm tonehole. Currently, the 3 mm tonehole is stuffed with a WD-40 straw. Hey, it solved most of the issues. 🤣

The 80 and III are mostly similar, though the III is brighter, freer blowing, and has superior altissimo response. Those little differences do have an impact up in this area of the horn, that's for sure.

 

The "curve" of the neck tube is far less important than it's length, "bore size", and taper. In an attempt to calculate the length and volume of the "missing cone", I took the measurements shown in the illustration below. Note that the neck in my study does not have the same taper throughout. In my reading of acoustics I have found that the harmonics of a saxophone are largely determined by its taper.

Curt Altarac has done an interesting study of the effects of the placement and pip opening on a saxophone neck. Saxophone Neck Experiment

 

Altarac's study is interesting. I assume that the dimensions are critical to any neck - or any saxophone, for that matter.

Any idea about how those internal measurements were taken (using an opened neck, inserting some sort of measuring tool?)? And, how many different examples were measured? Do all Selmer SBA alto necks (or any model's necks, for that matter) have the same measurements at the same places? Should we assume all necks are the same? How do we know?

I wouldn't be surprised to learn that each neck has its variables, but I just don't know. If each neck is different, even in the slightest way, I wonder what effect that would have on the overall instrument? And, what conclusions can be reached about any variables and where they occur on the tube? It seems to me that many of us have opinions about these things but an objective study involving many examples the same neck would be necessary to reach any conclusions. The variables could be endless. DAVE

 

Exactly! When players tell me that the plated version of "neck A" plays more ________ than the lacquered version, my first instinct is to think that variables in the manufacturing process altered something just enough to be noticed. Watching players (and advertisers) use different (and contradictory) adjectives for the same plating over the course of different pitches and instruments further reenforces my instinct. However, measuring everything accurately, having enough of sample group to make any definitive conclusions, and understanding the how's and why's of all things acoustics goes beyond my own knowledge and resources. I'm glad that some of the more knowledgeable techs on the forum are filling in some gaps. This is a very fascinating topic to me. Thanks everyone who has contributed so far.

 

Curt's study is amazing. He drew a few conclusions at the end that correspond with a few of my own observations.

- "As notes are played on pips lower down the neck, high notes get sharper and low notes get flatter."

This one was particularly interesting. I can only assume that a pip lower down the neck essentially acts as part of the high palm F's tonehole. In this case the air is leaking out in a way that would be similar to making the F tonehole larger. The larger the tonehole, the sharper the pitch gets. However, when the rest of the upper stack is closed, the low placed pip is now in a better position to vent the octave of the mid range notes. Moving the pip closer to the neck, while playing this same range allows for the pip to be more akin to a leak than a vent, which in turn causes the mid range to go sharper.


-"In general, pitch gets sharper as the pip diameter increases."

Once again falls back to tonehole size, and basic flute manufacturing theory. The larger the opening of the tonehole, the sharper the pitch gets. Curt's chart also showed that a pip opening of 3mm made the high F incredibly sharp. This is something I can personally vouch for with my Chinese neck before the modification.


-"The pitch gets flatter as the pip length increases."

This isn't surprising as adding length to the tube ought to make the pitch flatter. It's similar to how adding length to the bell can change a low Bb saxophone into a low A saxophone. I think it's also safe to conclude that adding additional length to each tonehole chimney would also flatten each corresponding pitch.


-"Tapered pips have somewhat similar intonation to pips with a diameter equal to the average of the min and max diameters of the taper."

This is purely speculation on my part, but I'm assuming that any possible taper in the pip would be too negligible to impact the average opening size. However, the effect on intonation by tapering other toneholes along the bore would be more noticable on mid-sized toneholes before tapering off to less noticable with larger toneholes given that all chimneys would be of equal height. A fly gets thrown into the ointment here if the tonehole chimneys are directly proportionate to the diameter of each tonehole. If that's the case, the effect on intonation should be equal on all toneholes with the equivalent taper.

- "A threaded pip has similar intonation to a straight pip with a diameter equal to its minor diameter."

Essentially, the threads are not taking up enough internal volume to really make a difference. Now I'm assuming that this would change with extremely exaggerated threads. However, even if one could accomplish this inside of a saxophone bore, the question remains as to why would you? Could you imagine the gunk that would be building up in between such threads? Given a lot of playing, and time, calcium, and other deposits would fill in those threads and greatly impact the volume of the bore. Any found advantage in creating such a horn would probably be offset by trying to figure out how to keep it clean. :lol:

 

SO many factors and SO many combinations of factors - I'm thinking a life-time of research would be necessary to pin down all the variables and what effect they have on each other. And that's only the necks!!

This is one reason why I always laugh when someone claims Brand X does this and Brand Y does that. We really don't know WHAT those brands do that may be unique to a brand. They are all just conical tubes of some general measurement. DAVE

 

Another factor could be at play in Curt's research.
He used a neck with many pips installed on it.
The mere existence of these protrusions into the air column, in such a crucial location of the air column, could have introduced turbulence that interfered with his results.

 

Also true. And what's fascinating about this are player preferences. If one grew up on vintage horns, they're used to more... flexible intonation, and the correction of that through voicing. They typically don't care for the more locked in, and correct, refinements in post VI Selmers or Yamahas. Conversely, players that grew up on modern horns are often thrown for a curveball when they try vintage horns for the first time. And I swear that there are more preferences on this topic than there are actual saxophonists.

 

Thanks for that clarification.
Perhaps the "nut" part of the thread was the part soldered to the neck.
I also wonder how much effort was made to keep the bore smooth where the plugs met the inside diameter. That would be quite difficult.