Can a digipot be used between an amp and speaker for volume control
Generally no.

Digital potentiometers are designed for signal levels and powers. Your amplifier output is much too powerful for this and the currents involved driving a loudspeaker will be too high for a digital potentiometer.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Standard configuration for volume control is to put the potentiometer - digital or analog - in the signal line before the power amplifier.