There are many quotes about the ebony clock in The Masque of the Red Death. Just after the paragraph describing the colorful rooms and what they contained, there is an entire paragraph about the large clock and the effect it has on the people at the party. It was to be found in the room decorated in all black (hence why the clock was ebony), and Poe describes it as gigantic, with the pendulum making “a dull, heavy, monotonous clang” as it swung back and forth. He then describes what happens to the party goers upon the sound of the chime, which he describes as “exceedingly musical” yet “of so peculiar a note and emphasis” that everything goes quiet—the people, the musicians, everything—and people go pale or become confused or nervous; but as soon as the chime of the clock is done, everyone goes back to their normal happy and carefree selves, and they promise themselves that next time the clock chimes, they will not be frightened. But every time the clock chimed, there “were the same disconcert and tremulousness and meditation as before”.
One quote regarding the effect of the clock is: “And, anon, there strikes the ebony clock which stands in the hall of velvet. And then, for a moment, all is still, and all is silent save the voice of the clock. The dreams are stiff-frozen as they stand.”
Overall, it is clear that this clock is not a normal clock, as the mere sound of its chimes strike up a strange anxiety in all who hear it.