A pager in your pocket is inaudible when it vibrates. That’s an infra-sonic “noise”. If you put a piece of paper in front of a subwoofer you should get plenty of visible motion. Furthermore, if you go to a club or theatre with decent speakers you will feel the bass.
Example: people feel earthquake tremors without hearing them (unless their china cups rattle and fall out of the cupboards, that is). In Jurassic Park the steps of the T-Rex were reflected in water before they were audible. It was just a movie, and yes there probably was some sound added in too by the audio engineers. But the principle is sound, so to speak. Low frequency audio is perceived as vibration or a thump that is felt.
Another possibility would be to observe some sounds that are normally too quiet or individually insignificant to be heard; a sensitive microphone in an ant farm, for example (aside from the rustle of movement, apparently ants ‘bark’ when there is danger).
If you have wood ants nearby (or maybe termites), listen carefully to an individual walking across the ground - nothing, now visit the nest and listen; in the case of wood ants, there is a distinct rattling rustle from all of their tiny legs (don’t stand still for too long if you are near a wood ant nest.