To help customers understand the benefit of servo control, I have constructed a display device to allow us compare damping control of cone movement between nonservo mode and servo at the same time. It should be displayed and demoed at room 2016 of Marriott. The objective is to demonstrate the sound difference one hears from our servo sub comes from better damping control of cone to resist external force. The idea is that cone should respond to input signal only. It should reject any external forced disturbance because any cone movement as a result can cause retransmission of sound. This idea is similar to the PSRR (power supply rejection ratio) of operational amplifiers. Examples of external force includes the standing wave/reflection within enclosures, or the reflection from floor with a down-firing subwoofer. One can clearly feel the added damping forced from servo operation. It is actually 3x better, not trivial. In addition, one can examine how this damping force diminishes when the cone is pushed in with nonservo operation in nonservo control. Sort of explain most conventional nonservo subwoofers give us impression the cone lost control quite easily. In contrast, the damping force is literally not changed with servo in the same position. The main reason is our sensing coil is super overhung design that it stays in the gap even when the driver coil is practically out of gap. Welcome everyone to drop come and play it for yourself.
