The gamepad speakers aren't the loudest, a bit quieter than a ds at full volume.
Also, you wired the input and output of the potentiometer backwards, the outputs are pins 2 and 3, and the inputs are 4 and 5.
Also, you wired the input and output of the potentiometer backwards, the outputs are pins 2 and 3, and the inputs are 4 and 5.
Place it with the pins pointing down and the 5-pin edge facing toward you. From left to right, the pins are:
1) Common (GND for audio use)
2) R1 Wiper (Out 1 for audio)
3) R2 Wiper (Out 2 for audio)
4) R2 End (In 2 for audio)
5) R1 End (In 1 for audio)