Subwoofer mode cancellation needs no equalization to fix boom

Evidence

The idea seems to have originated with Goertz et al. (2001), who used an arrangement of subwoofers on the front wall, generating an approximation of a plane wave that propagates to the rear of the room where a similar arrangement of subwoofers, appropriately delayed and polarity inverted, cancels the wave when it arrives. Ideally this eliminates standing waves and everyone in the room should hear good bass. It requires a perfectly rectangular room and at least four subwoofers to work well. The scheme was called double bass array (DBA). — Toole, Floyd E, Sound reproduction- the acoustics and…, 1604 (#expands, via linked claim)

Categorization

• XREF: connects to: Widespread sonic booms need not originate from supersonic sources; Opposite-polarity subwoofers can null a specific room mode’s coupling; Equalization masks a mode’s audibility but leaves the room itself untouched (+3 more)

Related

• Inverting a signal cancels sound at all frequencies when paths are equal (similarity 0.92)
• Active noise cancellation fails at high frequencies due to phase shift limits (similarity 0.90)
• Opposite-polarity subwoofers can null a specific room mode’s coupling (similarity 0.90)
• Delayed, inverted subwoofer arrays can cancel standing waves in rectangular rooms (similarity 0.90)
• Inverted signals cancel at all frequencies while delayed signals cancel selectively by frequency (similarity 0.89)
• Subwoofer placement itself can be optimized alongside DSP settings (similarity 0.86)
• Equal distances from two loudspeakers eliminate all room-induced destructive interference (similarity 0.83)
• Two subwoofers in opposite mode lobes can cancel room resonances without equalization (similarity 0.83)
• Double bass arrays keep high efficiency despite half the units cancelling (similarity 0.82)
• Optimal woofer placement makes boundary distances as different and non-multiple as possible (similarity 0.80)
• Optimized multi-sub systems can use much smaller subs at some locations (similarity 0.80)
• Opposing in-phase subwoofers cancel odd-order axial modes but amplify even-order ones. (similarity 0.79)
• Multiple independently-processed subwoofers tame room resonances for wider listening areas. (similarity 0.79)
• All subwoofers sound equally fast because rooms, not drivers, dominate bass time response (similarity 0.79)
• Moving a subwoofer away from a boundary toward a null reduces modal energy room-wide. (similarity 0.78)

Broader Connections

• Delayed, inverted subwoofer arrays can cancel standing waves in rectangular rooms #expands (0.85) — Toole, Floyd E, Sound reproduction- the acoustics and…, 1604
• Opposite-polarity subwoofers can null a specific room mode’s coupling #expands (0.82)
• Inverting a signal cancels sound at all frequencies when paths are equal #expands (0.80)
• Equalization masks a mode’s audibility but leaves the room itself untouched #complicates (0.78)
• Active noise cancellation fails at high frequencies due to phase shift limits #expands (0.72)