Compared to modern mouthpieces, historical mouthpieces have a number of differences that have a strong impact on playing behaviour and sound.
The entrance to the bore is sharp-edged, especially in the Baroque, which has a direct effect on the sound, which thus becomes very rich in overtones. In addition, the sharp edge helps to control the instrument, especially when it comes to bending. From the classical era onwards, the sharp edge became increasingly rounded and approached the modern form.
The mouthpiece rim was flat in the Renaissance and Baroque. This produces a brighter, more overtone-rich sound and provides more accuracy than a round rim. This rim shape, too, became increasingly close to the round form from the classical period onwards.
In addition, historical mouthpieces are longer than modern ones in a variety of cases. This makes the tone more stable and better guided, and also makes the response more secure and stable.