What is the damping factor between the driver and amplifier in Direct Servo subs?
Close to infinity. Keep in mind damping factor is not the same as the damping of bass extension. More accurately stated, damping factor is the ratio of speaker impedance vs amplifier output impedance. For most amplifiers, damping factor ranges from 20 (tube amplifiers) to 200 or even higher. In the past, higher values are preferred because they imply the frequency response of the amplifier is less sensitive to the speaker’s impedance. In a conventional (or non-servo) amplifier-speaker interface however, higher damping factor does not translate to real-world benefits because it does not include the impedance of speaker wires, or even the DC resistance of the voice coil for that matter. One should keep in mind, the voice coil DC resistance is not constant, rather it is temperature-dependent. A high power subwoofer driver means the voice coil can tolerate higher voice coil temperature. What is not often mentioned is that when the voice coil is at a higher temperature, the DC resistance al
