A single sound source near a reflective boundary creates a virtual second source
Evidence
There are several acoustical situations which 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 which 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 formed by the reflection and thus there are effectively two sources available to cause interference, as shown in Figure 1.28. This latter situation can often cause problems for recording or sound reinforcement due to a microphone picking up a direct and reflected sound component and so suffering interference. — David Howard, Jamie Angus, coustics and Psychoacoustics, 361
Categorization
Category: Causal Relationships
- SEED: Angle: how the ‘image source’ concept explains why wall-placed speakers, corner placement, or recording near surfaces sound colored — a bridge between textbook acoustics and everyday audio experience.
Related
- A single sound source near a reflecting surface creates interference via an image source (similarity 0.93)
- A single boundary reflecting sound off an omnidirectional source creates frequency-dependent interference lobes (similarity 0.87)
- Nearby reflective surfaces can load a source and boost its output (similarity 0.83)
- Room boundaries alter a sound source’s radiated power, not just its perceived sound (similarity 0.83)
- Wall boundaries alter loudspeaker output by modifying acoustic impedance seen by the driver (similarity 0.83)
- Reflecting walls are equivalent to mirror-image virtual sound sources (similarity 0.82)
- Sitting close to a rear wall creates early strong reflections that corrupt perceived sound (similarity 0.81)
- Reflections from adjacent walls create destructive interference nulls at one-half wavelength spacing. (similarity 0.81)
- Nearby walls amplify monopole but not dipole sound sources (similarity 0.80)
- Waves transitioning from bounded to unbounded space create interfering reflections (similarity 0.80)
- Room acoustics act as another system modifying the instrument’s output (similarity 0.80)
- A reflecting wall doubles total sound power output from any source (similarity 0.80)
- Reflected sound waves interfere with direct waves to create frequency peaks and dips (similarity 0.80)
- Room boundaries alter loudspeaker output through reflected image sources (similarity 0.80)
- Near-field sound measurement is unreliable when multiple source parts radiate simultaneously (similarity 0.80)