Some models provide adjustable completion tones, but alarms and operating sounds should not be treated as identical. Use only the documented sound settings for the appliance.
Understanding this situation
A desired quiet end signal is different from suppressing an unfamiliar warning without understanding it. Mechanical noises cannot be fixed through a sound menu, and a new repeated beep may be trying to identify a condition that needs attention.
A useful next step
Read the message or indicator that accompanies the sound before changing settings. If a completion tone is adjustable, follow the manual. Report warning patterns accurately and do not disable protective functions or ignore a new noise simply to make nighttime use less noticeable.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.