How do I fix laptop speakers popping when no sound is playing?

I suspect it is the power save mode kicking into action which is causing the popping sounds. Save the following into a file called audio-power-save-off

#!/bin/bash
for dev in /sys/module/snd_*; do
        [ -w "$dev/parameters/power_save" ] || continue
        echo 0 > "$dev/parameters/power_save"
done

and do the following:

chmod +x audio-power-save-off
sudo ./audo-power-save-off

and see if it helps