Which Bach technique involves repeating a melodic line or subject with a different contour, and is sometimes used in fugues?

Which Bach technique involves repeating a melodic line or subject with a different contour, and is sometimes used in fugues?

• A. Augmentation
• B. Mirror inversion
• C. Stretto
• D. Pedal point

Answer: (B)

Transforming a melodic line by inversion means turning the intervals around, so the line is heard with its directions flipped. When this inverted contour is used as a repeat of the same subject, it’s often described as mirror inversion—the theme is recognized, but its direction is reversed. In Bach’s fugues, this kind of move provides variety and contrapuntal unity: the same melodic material reappears, yet in a contrasting contour that keeps the texture lively. If the original line rises by a certain interval, the inverted line falls by the same interval, and vice versa. For example, an upward third becomes a downward third. That’s the essence of why this technique fits the description. Augmentation lengthens note values but preserves the contour, so it doesn’t involve repeating with a different shape. Stretto is overlapping entries of the subject, not contour change. Pedal point is a sustained bass with moving upper voices, unrelated to transforming a melodic line’s contour.

Transforming a melodic line by inversion means turning the intervals around, so the line is heard with its directions flipped. When this inverted contour is used as a repeat of the same subject, it’s often described as mirror inversion—the theme is recognized, but its direction is reversed. In Bach’s fugues, this kind of move provides variety and contrapuntal unity: the same melodic material reappears, yet in a contrasting contour that keeps the texture lively.

If the original line rises by a certain interval, the inverted line falls by the same interval, and vice versa. For example, an upward third becomes a downward third. That’s the essence of why this technique fits the description.

Augmentation lengthens note values but preserves the contour, so it doesn’t involve repeating with a different shape. Stretto is overlapping entries of the subject, not contour change. Pedal point is a sustained bass with moving upper voices, unrelated to transforming a melodic line’s contour.