Superposed sounds cancel or amplify locally without changing each other

Evidence

Even though sound waves pass through each other unscathed, they locally interfere with each other destructively or constructively, making the sound softer or louder. We must take the equation ψ(r, t) = ψ1(r, t) + ψ(r, t) literally; to find the pressure at r, we have to add the pressure from ψ1 and ψ2. If at that moment t and at that place r we have ψ2 = 0.001 and ψ2 = –0.001, then the two cancel (destructively interfere), and ψ = 0. These points are made clearer in figure 2.5, which shows two localized sound waves before, during, and after they occupy the same space. Interference takes place in the region of collision between the two expanding rings, but the collision has no effect on either ring as they propagate beyond the point of intersection. — Eric J. Heller, Why You Hear What You Hear- An…, 160

Categorization

Category: Causal Relationships

Related

• Inverted signals cancel at all frequencies while delayed signals cancel selectively by frequency (similarity 0.83)
• Inverting a signal cancels sound at all frequencies when paths are equal (similarity 0.83)
• Equal-amplitude sounds in phase double in amplitude while out of phase they cancel (similarity 0.82)
• Antiphase waveforms cancel when added together (similarity 0.81)
• Opposite-phase monopole sources cancel at a distance when separated by less than a wavelength (similarity 0.81)
• Adjacent compression and rarefaction regions can short-circuit and kill radiated sound (similarity 0.81)
• Equal distances from two loudspeakers eliminate all room-induced destructive interference (similarity 0.80)
• Relative phase and path distance determine whether correlated waves cancel or reinforce in space. (similarity 0.80)
• Waves transitioning from bounded to unbounded space create interfering reflections (similarity 0.80)
• Active noise cancellation fails at high frequencies due to phase shift limits (similarity 0.80)
• Adjacent surface compressions and rarefactions can cancel sound before it radiates. (similarity 0.80)
• The cancellation dip shifts to higher frequencies and weakens as measurement moves off axis. (similarity 0.79)
• Correlated sound sources create spatial interference patterns that uncorrelated sources do not. (similarity 0.79)
• Interfering sound waves pass through each other because their energy flow is preserved (similarity 0.79)
• Opposing waves cancel only momentarily because energy persists in kinetic form (similarity 0.79)

Broader Connections

• Active noise cancellation works by adding phase-reversed copies of background noise #exemplifies (0.90) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2565
• Inverting a signal cancels sound at all frequencies when paths are equal #exemplifies (0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 225
• Correlated sound sources sum to between zero and twice their individual amplitudes #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 267
• Delayed, inverted subwoofer arrays can cancel standing waves in rectangular rooms #exemplifies (0.80) — Toole, Floyd E, Sound reproduction- the acoustics and…, 1604
• Adjacent opposite-phase regions on a vibrating surface cancel their radiated sound #exemplifies (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 676
• Equal distances from two loudspeakers eliminate all room-induced destructive interference #qualifies (0.75) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 379