sentences:  Bailey and A.H. Radford in "Wireless World" (p483-486) magazine.The article postulated that energy from the rear of a driver unit could be essentially absorbed, without damping the cone's motion or superimposing internal reflections and resonance, so Bailey and Radford reasoned that the rear wave could be channeled down a long pipe.If the acoustic energy was absorbed, it would not be available to excite resonances.