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It is not lossless, there is the voice coil resistance, which absorbs the energy. It does not matter whether the resistance is internal or external. It is true that almost all audio amplifiers are voltage amplifiers with practically zero output impedance, but
ironically lot of problems would disappear in loudspeakers, if driven with current amplifiers. The main reason for using voltage amplifiers is just the electromechanical damping it offers at the low frequency resonance. The same would be achieved with acoustical
resistance elements behind the diaphragm - just like in many headphone drivers - but this is not currently done. Loudspeaker drivers from 30’s and 40’s often have basket openings covered with a mesh serving just this purpose. At mid and high frequencies the
driving source impedance does not matter as the diaphragm does not vibrate as a piston but bending waves are propagating along it. What matters there is the diaphragm internal damping, i.e. mechanical losses.
Ilpo
On 16 Dec 2014, at 07:30, Richard F. Lyon <dicklyon@xxxxxxx> wrote:
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