Operating a loudspeaker near three room boundaries imposes a 9 dB low-frequency rise
Evidence
- By placing the speaker carefully, with respect to the boundaries, one can eliminate some of the variation in the response. However, one still has a 9 dB rise in response at low frequencies. This is well known and the 9 dB rise at low frequencies is inherent in operating in an environment with three boundaries. In general, the lowfrequency responses of loudspeakers designed to be placed close to boundaries is tailored to compensate for it. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2193
By placing the speaker carefully, with respect to the boundaries, one can eliminate some of the variation in the response. However, one still has a 9 dB rise in response at low frequencies. This is well known, and the 9 dB rise at low frequencies is inherent in operating in an environment with three boundaries. In general, the low-frequency responses of loudspeakers designed to be placed close to boundaries are tailored to compensate for them. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2138
Categorization
- DEFINE: Key psychoacoustic/acoustic design fact: boundary-condition placement shifts low-frequency response by quantized amounts, useful for understanding how rooms shape what we hear.
- SEED: Angle: ‘Why every speaker you’ve ever owned lies about bass’ — the geometric inevitability of +9 dB at low frequencies and the industry’s compensating trickery.
- corroborated: 4 independent passages support this claim — David Howard, Jamie Angus, coustics and Psychoacoustics, 2193; David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2138
- XREF: connects to: Horn confinement amplifies siren output via proximity resonance.; Loudspeakers perform best only free-standing or flush-mounted in a boundary; Room pressurization creates a compliant bass boost below the first axial mode (+4 more)
Broader Connections
- Flush-mounting a speaker in a wall reduces the low-frequency rise to 6 dB
#qualifies(0.90) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2194 - Room boundaries alter a sound source’s radiated power, not just its perceived sound
#expands(0.90) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2134