Tuba after American bandmaster John Philip Sousa, resembles a hélicon with the bell pointed up (in the original models as the J. W. Pepper prototype and Sousa's concert instruments) and then curved to point forward (as developed by Conn and others). Some ancestors of the tuba, such as the military "bombardon", had unusual valve and bore arrangements compared to modern tubas. During the American Civil War, most brass bands used a branch of the brass family known as "saxhorns", which, by today's standards, have a narrower bore taper than tuba—the same as true cornets and baritones, but distinct from trumpets, euphoniums,
Tuba second harmonic (an octave higher than the fundamental). These alternative resonances are often known as false tones or privileged tones. Adding the six semitones provided by the three valves, these alternative resonances let the instrument play chromatically down to the fundamental of the open bugle (which is a 29 Hz B). The addition of valves below that note can lower the instrument a further six semitones to a 20 Hz E. Thus, even three-valved instruments with good alternative resonances can produce very low sounds in the hands of skilled players; instruments with four valves can play even lower. The lowest