While the key of E minor in Bach's works often features pieces that are very serious and express sadness, this prelude does not convey a serious aspect. This prelude modulates to E minor, G major, B minor, A minor, and C major (or at least gives that impression). As a performance tip, it is important to vary the dynamics and timbre according to these keys.

Starting from a majestic E minor, it modulates to G major in measure 9, but quickly returns to E minor in measure 13. Measures 13-14 form a two-measure sequence, and then modulate to B minor in measures 15-16, leading directly to a cadence. If measures 13-14 are played at a mezzo-piano dynamic, for example, playing measures 15-16 forte can emphasize the shocking modulation.

From measure 20, it begins in A minor, and a gentle C major appears as a sequence from measures 24-27, but it returns to A minor again, reaching a cadence in A minor at measure 31.

Finally, it concludes with E minor → G major → E minor. Based on these observations, performers should try varying the timbre and dynamics according to each key.