Three Woofers are Better than One
Three 7-inch woofers are arranged in PSB's three-woofer transitional array, where all the woofers combine to produce the longest wavelengths of sound in the lowest frequencies. At higher musical frequencies, woofers are strategically attenuated until only the woofer adjacent to the midrange is active, creating a perfect transition with uniform off-axis response. The position of each woofer, and the exact crossover slope, has been carefully optimized to reduce first acoustic reflections, also known as 'floor bounce'. Floor bounce is responsible for response irregularities, and occurs for all speakers unless compensated for, as in the Imagine T3. Another advantage to using multiple woofers is more efficient transfer of energy into the air compared to a single larger woofer. The varying positions also tend to excite a broader spectrum of room resonances, thus preventing the 'one note bass boom' that often occurs with powerful full-range speakers. Utilizing smaller cones with large motors results in higher sensitivity and more accurate piston motion of the cone for faster transient response and lower distortion.