A single sound source near a reflecting surface creates interference via an image 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

Categorization

• corroborated: 4 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 366
• XREF: connects to: A reflecting wall doubles total sound power output from any source; Reflecting walls are equivalent to mirror-image virtual sound sources — Eric J. Heller, Why You Hear What You Hear- An…, 515; Reflecting surfaces can extract wasted energy from an inefficient sound source. (+11 more)

Broader Connections

• A speaker near hard surfaces produces phantom image sources that color its sound #exemplifies (0.95)
• Room boundaries alter loudspeaker output through reflected image sources #expands (0.90)
• A finite source-to-wall distance creates a destructive interference null at the half-wavelength frequency #expands (0.85)
• Surface reflection reduces total sound power and favors high frequencies #complicates (0.75)