The picture below is of a mute cornett (diatonic piccolo trumpet) . The trumpet-like small cornett mouthpiece is inside the narrow upper hole of the wooden tube.
The picture below is a trumpet-like cornetti mouthpiece which is smaller than the trumpets (inner diameter from 12mm to 15mm, Trumpet mouthpieces have usually inner diameter 16mm-17mm.) .
If a mouthpiece with inner diameter of the cup of 13,5mm-14mm is attached to an oboe, it will give a modern type of cornetto (diatonic trumpet) with keys and more or less the fingering ofthe oboe. The sound compared to the trumpet is less loud because of the smaller bell and more sweet because the oboe is not made from brass metal.
The sound compared to the traditional of oboe with double reed is more smooth bass and melo , less penetrating and in generalmore human and pleasent. Neverthless as it is known the brass instruments and cornetti mouthpiece embouchure is by far more difficult in stability and pitch compared to that of double reeds.
The same applies if instead of an oboe we utlize a soprano saxophone with a cornetti mouthpiece with 14,5mm-15mm inner diameter of the cup. Even a french horn mouthpiece would fit and would give a very good 1st octave! It will become a DIATONIC FLUGELHORN OR CORNETTO with fingering chart more or less that of the soprano saxophone. The sound is very close tthe flugelhorn sound , and compared to it is slightly more instrospective and less loud because of the smaller bell compared to a flugelhorn. The pitch is a bit more volatile with the soprano sax body, when the same french horn mouthpiece is utilized both in the flugelhorn and the soprano sax, and easy changing in the embouchure compared to a flugelhorn, because of the smaller length tube of the soprano saxophone. But with a smaller mouthpiece of 14,5mm-15mm of inner diameter of the cup,as in wooden cornetto this pitch variability is improved. The fingering system of the saxophone played in such a way as a flugelhorn with a cornetto or french horn mouthpiece is by far more intuitive and straight forward as a diatonic instrument compared to the valves system of the flugelhorn which is better for the chromatic 12-notes scale rather than 7-notes diatonic scale.
The sound compared to the sound of the soprano saxophone is more smooth bass and melo , less penetrating and in general more human and pleasent . Neverthless as it is known the brass instruments and cornetti mouthpiece embouchure is by far more difficult in stability and pitch compared to that of single reeds.
