With this in mind, consider the opening of Prokofiev's Second Violin Concerto in G minor, which was premiered in Madrid on this day 81 years ago. It begins with a G, B-flat, D, E-flat, C sharp, and another D played by the soloist, and then this rising motive repeats in its entirety. The frequency at which the rising motive appears can also be labeled as a pitch. Prokofiev indicated a tempo of quarter = 108, which makes the motive's frequency a slightly low F sharp. While some commercially recorded performers roughly take that tempo, many others tend to go slower: around an F or even around an E for the rising motive. But Nathan Milstein, in a live recording from 51 years ago, not only plays it faster than what Prokofiev requests (and with relatively little rubato), but also plays the rising motive "at a G," several octaves below the open-string G he plays to begin the concerto, a G that matches the opening tonal center of the concerto.
Prokofiev follows this rising motive and its repetition with a descending motive (D-C-Bb) and its embellished repetitions that extend the motive lower and longer by one suffixed note with each repetition. However, thanks to durational reductions of interior notes, each descending motive still takes up the same amount of time; therefore, the frequency of the descending motive can still be labeled by a single pitch letter. Milstein's tempo for this portion puts the descending motive's frequency at around a B. Although the descending motives neither contain a B nor are in B, the immediately following orchestral statement of the ascending and descending motives is transposed to start on, and position the tonal center on, B.
The movie below demonstrates these pitch-tempo relationships.
Thanks to Debbie Rifkin for encouraging me to think about this concerto.