As a rule notes from the 2nd natural are used, so the 2nd natural of the 7th position makes E2 the lowest note. Overblowing is generally used up to the 8th, 9th or 10th natural. Only very proficient players can overblow as far as the 12th natural.
In the 1st position the tube is at its shortest – and therefore natural – length (about 290 cm), the longest length (about 410 cm) being reached in the 7th position. This difference of 120 cm means that the trombonist has to move the slide over a distance of about 60 cm. It is therefore very difficult to play fast passages in distant positions accurately.
For each note, the trombonist tries to choose the position that requires the lowest natural – naturals beyond the 8th are seldom used in the lower positions, since low naturals respond better from a higher position. For example, F4 can be played as the 6th natural in the 1st position or as the 8th natural in the 6th position. If possible, players choose the first fingering.
A second criterion for the choice of position is the similarity of the sound quality, which is also influenced by big differences in the degree of overblowing.
Between the pedal in the 1st position (Bb1) and the 2nd natural of the 7th position there is a gap which can only be filled with the help of a fourth-valve (F valve) or fifth-valve (Eb valve) as used on the tenor-bass trombone. Modern orchestral compositions call for all seven pedals, and on modern trombones with their wider bore these speak relatively well. Pedals were discovered in the 1830s and were originally very rarely asked for because they were so hard to play. Their tone quality was often described as rough and without substance. However, their dark and metallic sound then prompted composers such as Berlioz (Requiem: Hostias), Messiaen (Les Couleurs de la Cité Celeste) and Alban Berg (Wozzeck, Act 2) to call for pedals.
The Vienna Symphonic Library decided not to include a sample of the pedals of the tenor trombone because notes of this type can also be played in superlative quality on the bass and contrabass trombone.