The Trumpet and Its Bore Size – How Critical is It?

by Andrew Naumann

There are many choices when faced with buying a professional quality trumpet. One of the first decisions most players encounter is which bore size should I choose? Many players assume that a larger or smaller bore size will create the type of feel or blow they need (i.e. more open or a more resistant air stream). This article will help you understand the concept of bore and help you realize its importance when choosing a new trumpet.

First, the design of the bore is not the size of the hole in the piston but rather it is determined by the size of the inside slide tubes of each of the valve slides (1st, 2nd, and 3rd valve slides) and the tuning slide. The leadpipe and bell are conical. The general bore sizes offered on Bb trumpets range from .459″ to .468″.

I would like to first say that the differences in bell size and leadpipe design will change the resistance of the instrument, tonal production, and rate of airflow much more significantly than the overall bore size. For these reasons, you should not concern yourself with bore size more than understanding the different leadpipes and bells for each trumpet you sample. Many professional trumpet manufacturers describe the shape of the bell as well as the leadpipe in detail along with giving a bore size. The significance of leadpipe design and bell design has a larger overall effect on the quality of sound and blow than bore size. With that in mind, when looking for your new trumpet, pay attention to the detailed descriptions of the bell and leadpipe and how they affect your playing and overall concept of sound you are trying to achieve.

Generally, the rate of taper in a leadpipe defines the quality of blow (open or resistant). A slower taper creates a more stable, resistant air stream and a fast taper creates an open free-blowing air stream. As for bell design, larger bells produce a dark, free-blowing feel and medium-large bells offer a more controlled, brilliant tone. For example, if your concept of sound involves a darker tone, it would be best to begin with a trumpet that offers a larger bell in conjunction with a slower tapered leadpipe to help balance airflow. My experience has led me to believe that the best playing instruments are balanced within themselves. Large bells with medium leadpipes or large leadpipes with medium-large bells. This balance usually creates the optimum airflow you are looking for.

Where does bore fit into all of this? Basically, it puts it last on the priority list. Balance is what you are looking for. A balanced trumpet will offer a higher quality of sound with more stability and endurance for your embouchure. The ease of playability will encourage your development and ultimately produce higher quality performances.