Reflecting surfaces can extract wasted energy from an inefficient sound source.

Evidence

Several acoustical situations can cause interference effects. The obvious ones are when two loudspeakers radiate the same sound into a room or when the same sound is coupled into a room via two openings that are separated. A less obvious situation is when there is a single sound source spaced away from a reflecting boundary, either bounded or unbounded. In this situation, an image source is Position (in wavelengths) or relative frequency FIGURE 1. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 366 (#expands, via linked claim)

Categorization

• XREF: connects to: Noise represents wasted energy in any engineered system — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 677; A reflecting wall doubles total sound power output from any source; Curved surfaces concentrate sound locally while draining power elsewhere in the room (+6 more)

Broader Connections

• Passive devices and even walls can amplify sound without power #corroborates (0.90)
• A single sound source near a reflecting surface creates interference via an image source #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 366
• Nearby reflecting surfaces constructively pile up wave reflections to amplify sound #corroborates (0.85)
• Noise represents wasted energy in any engineered system #expands (0.80) — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 677
• Curved surfaces concentrate sound locally while draining power elsewhere in the room #qualifies (0.80)
• A reflecting wall doubles total sound power output from any source #contradicts (0.75)
• Off-axis wall reflections arrive substantially attenuated relative to the direct sound. #qualifies (0.75)
• Wide-dispersion speakers plus room reflections create listener envelopment. #expands (0.75)
• Flat surfaces reflect low-frequency sound specularly but scatter high-frequency sound #qualifies (0.75)