Direct answer
Calibration is essential if the goal is consistent, intelligible sound rather than simply making the system loud. A professional process verifies wiring and polarity, measures levels and delays, aligns crossovers and subwoofers, evaluates frequency and time behavior, and then listens for problems the measurements do not explain. Room-correction software is a tool within that process, not a replacement for good placement or acoustic design. Multiple subwoofers can reduce seat-to-seat bass variation when positioned and optimized as a system; they are not merely for adding more bass.
The right subwoofer count depends on room geometry and the listening area. Measure before purchasing extras, and reserve enough processing and amplifier capability for independent optimization when needed. CEDIA/CTA RP22 describes objective verification for immersive systems, while manufacturers such as StormAudio document multi-subwoofer and room-correction capabilities.
Sources and technical references
Use the organizations responsible for a product, platform or standard to confirm current specifications and compatibility.
How this answer was prepared
Camelback Smart Homes publishes this FAQ library for homeowners, design professionals, builders and property teams comparing integrated technology. Answers begin with the practical conclusion, then explain the factors that can change it.
Limitations: This is general educational information, not a site-specific design, quote, code determination or compatibility guarantee. Final requirements depend on the property, construction, infrastructure, equipment versions and project goals.