Every enclosed air space has a natural pitch set by its dimensions. When a sound frequency matches that pitch, the air inside vibrates strongly and grows louder. This experiment tests that effect across three sealed plywood enclosures of different depths, each fitted with an identical 8-inch speaker. Playing test tones at six frequencies and recording decibel levels one meter away, you find that the larger enclosures produce a flatter response across all frequencies. The smallest enclosure, by contrast, boosts certain mid-range frequencies above the baseline — making some tones noticeably louder than others.