Connect EasyVR differential pwm audio output to an amplifier

My EasyVR shield has two PWM outputs that connect to a speaker. They also included a line out that could be connected to an external amplifier. When I try to use this line out connection, the resulting audio is less than impressive. The biggest issue being that it sounds as if the audio is clipping. If hooking the speaker directly, PWM0 goes to one terminal on the speaker and PWM1 goes to the other. But on the audio output, PWM0 goes to Left and PWM1 goes to right. The two signals alternate so that it pushes and pulls the speaker in both directions using ground as a reference… My guess is that I need to hook these two outputs through a low pass filter to smooth out the square edges, then each to separate op amps to offset the voltages and then feed into a third op amp that drives one input on an audio amplifier… Is my approach generally correct? Or should I have the low pass filter elsewhere, such as at the output of the third op amp? Do I need three op amps? Or will one suffice?