Doubled bass in first inversion · Rules
In first inversion, the bass is not doubled when it is not a tonal degree (III, VI or VII). If the bass is a tonal degree (I, II, IV or V), doubling it is correct.
- Doubled bass in first inversion: In first inversion, the bass is not doubled when it is not a tonal degree (III, VI or VII). If the bass is a tonal degree (I, II, IV or V), doubling it is correct. (Piston, ch. 6, p. 69)