IqAudiO Hi-Fi HAT
Listen to high-definition audio on your Pi, and breathe smart life into your old, dumb hi-fi.
The Pi’s multimedia capabilities were pretty impressive when it was released, particularly the Videocore engine and HDMI port. But one area where it's always been sorely lacking is the quality of the analogue audio output. This is a shame as your Pi could otherwise be used to turn your dusty old hi-fi into a full-blown smart speaker system.
The nitty gritty runs something like this (and we encourage audiophiles to write in and correct us if we stray too far from the truth here). The analog signal is generated from digital signals, and those are limited by the PWM (pulse-width modulation) clock to a resolution close to 11-bit (read more about PWM in the box, below). This is fine for beeps and bops, but plug it into your fancy amplifier and things will sound hollow, lacking in range. There headphone jack will also pick up noise and static from other components.
Sounds good
To our rescue, then, come a variety of DAC (digital analogue converter) HAT boards that enable faithful audio reproduction for not much money. We tested the IQAudiO DAC+ HAT, which makes glorious 24-bit 192kHz audio reproduction possible. It takes the digital audio signal from the Pi via the I2S protocol and delivers it to its own high-fidelity DAC. There are other manufacturers too, such as HiFi Berry and Allo, which offer a separate reclocking unit to circumvent oddities from resampling audio signals. Some HATs even feature a built-in amplifier, so you can make a tiny 35 watts per channel boombox. We preferred the idea of using our quality 90s amplifiers though, and found IQAudiO’s offering produced a decent sound. We also found out that our neighbours don't like psytrance.
Turning your Pi into a smart audio hub is easy with the Volumio distribution. It’s available for PCs, Pis and other boards; grab it from https://volumio.org/getstarted. Once you’ve flashed the SD Card, fire up your Pi and connect it to the hotspot it sets up from another device. If you’re Pi doesn’t have wireless (or has an unsupported wireless chip), then use a cable to connect it to your router.
VolumeIO has partnered with Allo to make the Nanosound player, which is made of a Pi and one of Allo’s highgrade DACs fitted with a custom OLED display. It’s all housed in a nice box (available in a variety of colours) with playback and power buttons. It also comes with a remote control, which can even turn the Pi on and off thanks to wake-up circuitry in the DAC board.
Besides VolumeIO, you could just as well use MPD to serve your music. The MPDroid program enables this to be controlled from Android Phones, and a huge number of clients are available for Linux. Mopidy ( www.mopidy. com) combines MPD with a web interface and is another popular choice turning Pis into digital jukeboxes. Better still, extensions make it possible for Mopidy to connect to services such as Spotify, Soundcloud and Google Play Music.