A word of caution to anyone interested in the details; the marrying up of a transconductance amplifier with a loudspeaker is far from simple, The acoustic loading of the driver in its enclosure has a significant effect on the instant impedance of the voice-coil; a factor to remember is that sound is produced as a function of acceleration of the cone movements which is a result of changes in the currents in the circuit. all this means that the voltages appearing on the output terminals of the amplifier are not representative of the acoustic output!
On a previous post I inferred that a loudspeaker driver is ‘damped’ by a low amplifier output impedance (damping factor). Just to be clear, this is only the case at or near the resonant frequency of the driver in its enclosure. The requirement for a super-low damping factor is one of the myths of the audio business. 🙄