[whswhs]

In Enhanced Senses, I suggested that critical success on a Stealth roll meant 10 dB of noise (quiet breathing, audible at 1"); success meant 40 dB (leaves rustling, audible at 9"); failure meant 60 dB (conversation, audible at 1 yard); and critical failure meant 90 dB (as loud as a shout, audible at 8 yards). You could plug this into the general Hearing rules and assign penalties based on range. For a failed Stealth roll, for example, you would have an unmodified Hearing roll if you were 1 yard away.