Diminished Fifth Resolutions

A diminished fifth (a tritone) should not resolve to a perfect fifth

Description

Moving from a P5 to a d5 is allowed. This is called "unequal fifths". This motion however can often be confused with moving the other direction. Having a tritone often implies a specific resolution. The two notes of the tritone are typically a dominant 7th (which should resolve downwards) and the leading tone (which should move upwards). Moving from d5 to P5 will not fit that resolution.

Example

In the example above, the spacing in the middle chord between the alto and the tenor is a diminished fifth. These then move to a perfect fifth in the last chord. In this case, the F in the alto should have resolved to an E since it was the dominant 7th of the chord.