One of the notable deficiencies of the Raspberry Pi is its sound capabilities. The built-in sound is driven by pulse-width modulation, a hack that won’t produce hi-fi sound via the device’s 3.5 mm combo jack. Basically, the dynamic range of sound output through the headphone jack has a restricted dynamic range. Fortunately, there’s a universe of add-on digital-to-analog converters (DACs) and even analog-to-digital converters (ADCs) if you need inputs as well.
These include four official Digital-to-Analog Converter (DAC) HATs (Hardware Attached on Top add-on boards), once branded IQAudio before the Raspberry Pi Foundation acquired IQAudio in 2020. These official boards offer a couple of levels of sound quality, and some include high-resolution sound and an integrated amplifier or headphone amp. Of the many third-party sound HAT brands, HiFiBerry is perhaps the most well-known, alongside brands like Raspiaudio, Audio Injector, Pirate Audio, Pimoroni, and Allo BOSS.
Each model has slightly different features, but most are DAC HATs that convert digital audio to analog output. Few include an ADC to digitize analog audio, other than perhaps support for piezo microphones or onboard MEMS mics. When you do find a good ADC/DAC HAT, you’ll typically find that the price is quite a bit higher and starts to enter the range of cheaper professional audio interfaces like those from M-Audio and PreSonus. However, if all you need is the ability to play internet radio, Spotify, and the like, a DAC should serve you well in any number of projects.