In his classic text, Orchestration, Cecil Forsyth talked about brass instruments being classified into two categories – whole-tube instruments and half-tube instruments.
Whole-Tube Instrument – a brass instrument capable of playing its fundamental pitch (the so-called pedal tone).
Half-Tube Instrument – a brass instrument that cannot play its fundamental pitch.
Forsyth was never clear as to which instruments fell exactly into what category. In general, he stated that tubas were most definitely whole-tube instruments while trumpets and cornets cannot. He neglects to mention trombones in either category, but includes passages that show pedal tones.
What makes an instrument whole- or half- tube?
There are two factors. One is how wide the bore is. This can be seen best with trombones. Trombones, except for the bell flare, are completely cylindrical in their bore. The narrower the bore of a trombone, the harder it will be to produce pedal notes. The modern Bass Trombone is the exact same length as the Tenor Trombone, however, the Bass Trombone has a much wider bore, and thus, the pedal notes are easier to produce on that instrument.
The second factor is how conical the bore of the instrument is. On average, a B-flat Flügelhorn has a smaller bore than a B-flat Trumpet, but due to the Flügelhorn’s wide conical bore, the Flügelhorn can play pedal notes, whereas a trumpet cannot.
The designation of whole-tube and half-tube is a muddy one. It’s probably best not to worry about these terms and instead focus on what each instrument is capable of.
I now present a list of all the brass instruments and their pedal capabilities.
- The modern Double Horn can produce pedal notes, but only on the B-flat side. The pedal F is a normal note. Pedals on the F side might be feasible, but are not in use and are highly unreliable.
- Pedal notes are harder on Wagner Tuben than on Horn. They are to be avoided.
- Pedal notes might be playable by some players on some instruments, but their usage is only for the practice room. These notes have no musical quality. Some Bass Trumpets may have pedal capability, but they are not recommended.
- Cornet pedals are like trumpets. Pedals are not playable.
- Both instruments are capable of playing their pedal notes.
- Pedals are widely used. Pedals on Alto Trombone will be weak, but are playable. Pedals are a natural part of the Bass Trombone’s range. Pedals on Contrabass Trombone are playable, but at the lower limit of what human lips can do.
- As this instrument has a larger bore than Bass Trombones, it will be able to produce the pedal notes (though I can find no evidence of their use).
- All pedals are possible. except on the lowest tubas, which are harder due to the limits of human lips.