Get better sound from your Raspberry Pi by replacing its analogue audio output
Raspberry Pi Speaker Expansion Board Gpio Audio Amplification Pwm Sound Card For Zero/3b/4b - Demo Board - AliExpress
How to Build a Raspberry Pi-Powered Multi-Room Audio System | Tom's Hardware
Pulse Width Modulation (PWM) on the Raspberry Pi with Python programming.
Raspberry Pi Raspberry Pi Pwm Generation Using Python And C | Ras...
Amazon.com: Audio HAT Module for Raspberry Pi 4B/3B+/3B/2B/B+/A+/Zero/Zero W/Pi Zero WH,WM8960 Hi-Fi Sound Card HAT Stereo CODEC, Play/Record : Electronics