APPENDIX

measuring a bore profile

Measuring a bore profile is quite simple, actually, yet quite some work:

Start with marking lengths in centimetres on the neck and body. Zero length is at the entrance to the neck. A flexible tape measure is a boon (take a tailor's tape measure of which you cut off a narrow ribbon); a soft pencil or a felt pen for making your markings (felt pen ink can be removed easily with methylated spirits)
Next, take outside diameters and subtract twice the wall thickness. The tube will not be accessable at all places because of ribbons or pillars and you will have to search and choose. Try to take a measurement each centimetre in the neck; at least every five centimetres on the body; bottom bow every 2 or 3 centimetres; the bell five, except for the final few centimetres.
Wall thickness can be hard to establish. I made myself a special vernier calliper which can work around a bulge, so that I can take a wall thickness even at a rolled tone hole. 0.6 millimetre is a common size in sopranos, altos and tenors, which makes: outer diameter minus 1.2 (antique instruments are sometimes built out of 0.5). Baritones are often built out of 0.8 mm. Sometimes there is a subtle shift in wall thickness, for instance in the neck from 0.7 to 0.6, caused by the production process (forging..) Simply neglect this.
Everything is always out–of–round. You can tackle this problem by taking diameters in different directions and calculating an average value. In wide tube parts (a bell) with a pronounced out–of–roundness take the circumference with a tape measure and recalculate this to a diameter. For accuracy, you should take care that the tape measure is quite thin, preferable made out of paper.
Accuracy
- length: not any more accurate than a centimetre – in bows anyway you will very soon lose any greater accuracy.
- diameter: not any more accurate than a tenth of a millimetre. The inexactitude of the object makes that a tenth of a millimtre is already the maximum that can be accounted for. Only in the neck I sometimes use pluses or minuses for a an undefined 'something more than' or 'slightly less than', without wanting to attach a numerical value to it.
Mark down in the table where one tube part ends and where another one begins. The end size of one tube part certainly is not the same as the opening size of the next, although you might expect so.

Measuring a bore profile. The easiest way to determine lengths in a bow is to first mark the central axis and only then pencil down lengths.

The picture shows the vernier calliper mentioned in the text which can work around a bulge.

The tailor's tape measure in this picture is for circumference measurements – take care to use a very thin one.

measuring intonation

In intonation measurements we have to deal with the nasty natural flexibility of the saxophone: you can play as in tune or as out of tune as you want. Yet, the procedure is simple: take a graph paper, a tuning indicator with a scale in cents and play long notes. You must do as little as possible to correct your intonation. To counteract involuntary influence, the roles of the one who blows and the one who takes the measurements can be divided among two different people. You can alternately play chromatics and intervals and be keen to keep embouchure tension as much as the possible on the same level. We're dealing with the behavior of the instrument, not with the possibility of the musician to correct it. But above all, take averages of several measurements before you mark a value on paper.

Then tune your instrument a little down or up and start all over, so you get bundles. The more measurements you'll take, the more you'll gain insight into the behavior of the saxophone. And if you take the net volume of the mouthpiece with a small graduated cylinder (seal the opening of the neck with cork, cooking foil or wax and put the mouthpiece back in place), you will get a fair comparison of the tuning behavior between different mouthpieces as well.

The picture you get remains an rough sketch of the instrument behaviour, but a reasonable one.