This is a fugue where calm time flows slowly. Let's consider the subject to be long, spanning from measure 1 to measure 8. The peak point of this subject, if we take the example within these measures 1-8, is the C in measure 3, which is at the highest position; from here, it gradually descends following a sequence, so it is reasonable to decrease the volume accordingly.

Consequently, the E-flat in measure 1 should ideally be played at a relatively soft volume. Within these measures 1-8, no other voices are involved, so this is acceptable; however, when other voices enter, the most difficult sound to hear is the first note of this subject. This is because it is only a single whole note, and its sustain is obscured when other voices enter.

Therefore, it is essential to play the first two notes of the subject with a relatively loud volume to ensure it is recognized as the subject. The subject of this fugue can be somewhat difficult to recognize in this sense, so ensure the first note of the subject is clearly audible.

Note that some subjects are hidden, like the tenor in measure 53, and do not begin with a whole note. The G-flat in measure 68 is a shocking note. Emphasize it.