One approach to upscale. These are systems that sound particularly good. Extended response, held transients, stereo imaging, soundstage, quality stamps. This is not the place to look for the fault.
They like a little volume, minimum 50m3, dedicated to listening to music. A small auditorium character is a good picture of what they like. In a living room with TV, armchairs, sofa, furniture, a little crowded, unfortunately. Good sealed rooms are there, to me it seems more at ease.
A "normal" amp enough.
Harmonic distortion rate and the damping factor are of no importance. Indeed, this system without conical membrane and without coil does not produce against reaction. The membrane vibrates but does not move back and forth and there is no coil, so no return to the amp.
Furthermore the impedance is almost linear from 20Hz to 20kHz, between 3 and 8 ohms. Whereas an HP "normal" can vary from 4 to 35 Ohms depending on the frequency and this can hinder a somewhat likely amp.
Rid of these phenomena against feedback, harmonic distortion and impedance the amp much easier to get out at the square and therefore serious sharper and mid / treble transparent.
An ordinary transformer of 250Va for 2x100W sufficient.
I had worked with or upscale tapping, Elipson 4240, JMR opus, JBL 4311 and 4313 for the best-known, well it is the MG-1c that gave me the image of the symphony fairer and with more ease.