I was just reading Bob Carver's white paper on the principles behind his True Sub. Fascinating stuff--a recommended read.
http://www.nortek.net/learning_center/audio-video/sunfire_sunwoofer_white_paper.htm
His strategy involves maximizing the back-EMF from the driver's voice coil to limit the amount of current flow and resulting heat. To overcome the back-EMF, he specs a (theoretical) 2,700W amp (that is, capable of 104V which would push 2,700W through 4 ohms). However, the large amount of back-EMF boosts the reactive component of the impedence to the point that the amp almost always sees a much higher impedence. He cites this as the basis for the high relative efficiency of his True Sub (An 11" cube sub that puts out 112dB @ 20Hz while drawing all its power through a 6A slow-blow fuse must be doing something very right!)
Anyhow, this got me wondering if giant back-emf numbers relative to the voltage capability of an amp cause most amps problems. As long as there is voltage to drive an impedence, Are there any practical concerns that would put a cap on how much back-EMF you can expect an amp to handle with grace? Are there any special provisions that should be built into such an amp?
Bill
http://www.nortek.net/learning_center/audio-video/sunfire_sunwoofer_white_paper.htm
His strategy involves maximizing the back-EMF from the driver's voice coil to limit the amount of current flow and resulting heat. To overcome the back-EMF, he specs a (theoretical) 2,700W amp (that is, capable of 104V which would push 2,700W through 4 ohms). However, the large amount of back-EMF boosts the reactive component of the impedence to the point that the amp almost always sees a much higher impedence. He cites this as the basis for the high relative efficiency of his True Sub (An 11" cube sub that puts out 112dB @ 20Hz while drawing all its power through a 6A slow-blow fuse must be doing something very right!)
Anyhow, this got me wondering if giant back-emf numbers relative to the voltage capability of an amp cause most amps problems. As long as there is voltage to drive an impedence, Are there any practical concerns that would put a cap on how much back-EMF you can expect an amp to handle with grace? Are there any special provisions that should be built into such an amp?
Bill