Along with the mouthpiece, the leadpipe (or mouthpipe) is one of the most significant and relatively easy modifications you can make to your horn. As with mouthpieces, a leadpipe change can radically alter the playing characteristics of your instrument. Digging back through some of my old materials, I came across a clinic handout from Walter Lawson, circa 1980 (before my time, but I must have picked it up along the way at a horn workshop somewhere). In the handout, he lists some of the ways a leadpipe can be altered, and the corresponding effects.
1. The ease of register – A short taper provides an easy high register, but the low register lacks power and concentration of sound. A long taper gives strong low notes but is difficult in the high register in that it requires precise lip control and intense mental concentration.
2. Alloy – A mouthpipe made from a corrosion-resistant alloy is important because this tube is more exposed to the chemicals and food particles blown into the instrument. The taper is most critical inside the mouthpiece and will be adversely affected by corrosion buildup.
3. The center of sound or efficiency of the horn in amplifying the sound generated by the lips – A mouthpipe with a large cubic content will slur easily, but the harmonics will not be as centered or stable as a mouthpipe with smaller cubic content will produce.
4. Pitch of the harmonics and relative intonation between them – This is controlled by variations in the rate of taper inside the mouthpipe.
The handout is full of lots of other great practical information, and I will most likely be posting further on it in the future. If you are considering having a custom leadpipe made for your horn, check out some of the makers (and their websites) below.