What is an A-Period enclosure?
An AP subwoofer system is one which employs 2 enclosure volumes coupled with a purely resistive element, the AP Mat. When such a system is properly designed, it is possible to control the woofer cone movement by the energy transfer though the precision acoustic resistance of the AP Mat. The completed system will be considered A-periodic, or over-damped with a Q well below 0.7 Qts. In contrast, most car audio systems are grossly under damped, with Q’s greater than 0.8 and higher. These high-Q systems have poor transient response, nasty peaks in their frequency response and high rates of roll-off. The result of controlling cone motion with a resistive AP Mat is a very low system Qt. A-periodic systems feature excellent transient and phase response, smooth frequency response and extended very-low frequency reproduction with quicker attack, less bass hangover and lower cone distortion.
