The Twelve-Bar Arrangement Deadline
A student must submit a 90-second arrangement of a 12-bar blues for a four-part ensemble: trumpet, tenor saxophone, trombone and rhythm section (piano, bass, drums). The brief requires a written score and a notation software file. The student has drafted a head that states the 12-bar theme twice, then a solo section of four choruses (each 12 bars at 120 bpm), then a final head. At 120 bpm a 12-bar chorus lasts 24 seconds. The student's draft runs to roughly 4 minutes. The teacher notes the draft also gives the trumpet and trombone the same melody in octaves for the entire head, and the saxophone has no written part in the solo section. The submission is due in five days.
1. Calculate the timing problem and propose a structural revision that meets the 90-second brief while preserving the arrangement's character.
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At 120 bpm, one beat is 0.5 seconds, so a 12-bar chorus in 4/4 is 48 beats = 24 seconds. The draft is: head (24 s) + four solo choruses (96 s) + final head (24 s) = 144 seconds, i.e. 2 minutes 24 seconds, not 4 minutes - the student has overestimated. Even so, 144 s exceeds the 90 s brief by 54 s.
A workable revision: head (24 s) + two solo choruses (48 s) + final head (18 s, with the last four bars shortened or a tag) = 90 s. Alternatively, keep three solo choruses but raise the tempo to about 144 bpm, which shortens a chorus to 20 s: head 20 + three choruses 60 + head 10 = 90 s. The first option is safer because it does not alter the feel.
The revision should preserve the head-solo-head shape, which is the defining formal characteristic of a blues arrangement, and should keep at least one full solo chorus so the improviser has room to build. Trimming the final head rather than the solos protects the arrangement's identity. The student should also write out a solo roadmap (chord symbols, guide tones, suggested licks) so the score remains complete.
2. Diagnose the scoring problems in the draft and explain how to fix them within the remaining time.
Read the worked answer
Two problems stand out.
First, trumpet and trombone doubling the melody in octaves for the entire head creates a thick, homogeneous texture with no contrast and risks balance problems, since the trumpet will dominate in the upper register. Fix: use the octave doubling only for the first four bars as a strong opening, then split into harmony - trumpet on the melody, trombone on a guide-tone line or a third/sixth below - and bring the saxophone in on a countermelody or on the last four bars. This gives the head an arc and uses the ensemble's range.
Second, the saxophone has no written part in the solo section. In a scored arrangement every player needs a written role, even during solos: backgrounds, pads, guide-tone sustains, or written fills. Fix: write two-bar background figures for the saxophone behind the trumpet solo, and have the trumpet and trombone play written riffs behind the saxophone solo. This also solves the texture problem and demonstrates arranging craft, which the marking key rewards.
With five days, the student should prioritise: (1) cut the structure to 90 s, (2) write the saxophone backgrounds, (3) vary the head voicing. These are high-value, low-risk edits. Re-notating everything is not feasible and not necessary.