Multiple subwoofers allow cheaper units at positions needing reduced drive

Evidence

If the same subwoofer is used for the initial measurements, and it is found after optimization that some locations are not driven to full output (the gain is reduced by 6 or 12 dB, for example) this means that significantly smaller, lower power, subwoofers can potentially be used at those locations, with the only difference being lower power. A 6 dB reduction is 25% of the 0 dB power, and a 12 dB reduction is 6.3%, so much smaller, less expensive subwoofers can be employed if desired, however they must have similar bass extension to be good substitutes. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1616

Categorization

• XREF: Practical cost-savings implication connects to any loudspeaker/room-system design discussion; a 6 dB gain reduction means wattage needs drop to 25%.