Organ builders exploit a pitch illusion to extend sub-bass without actual low pipes

Evidence

The illusion produced by the combination of organ pipes to produce a sensation of pitch lower than any note actually sounding is also used in organ pedal resultant bass stops. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1694

Categorization

• STORYSTEM: A world where instruments are built on illusory foundations — sound engineers conjuring bass from harmonics, listeners hearing what physics cannot provide — echoes questions of perception vs. reality.