tonistry.

Connections & formats

I2S

Also called I²S, IIS, Inter-IC Sound

I2S is the raw digital audio bus that chips inside a DAC or CD player use to talk to each other, carrying the data and its clocks on separate lines. A few boutique DACs expose it on an HDMI-style socket as an external connection.

Master clock (often)Bit clockWord clock (L/R)DataLRReceiverUSB, S/PDIFDAC chip
I2S carries digital audio between chips on separate lines: a bit clock, a word clock that marks left and right samples, the data itself, and often a master clock. Consumer I2S on HDMI-style sockets has no standard pinout.

Inside almost every digital audio device, the DAC chip receives I2S. S/PDIF and USB exist to package that signal for a cable and then unpack it again. Sending I2S directly skips the packaging, which supporters say lowers Jitter and sounds cleaner.

The catch is that I2S was never meant to leave the circuit board. There is no standard pin-out for the HDMI-style plug, so a cable that works between one pair of devices may not work, or may connect the wrong pins, between another. Rates and DSD support vary too. It is mostly found on transports and DACs from makers such as Denafrips, Holo Audio and PS Audio.

Where you’ll see this on tonistry.

  • I2S is one of the connection types members pick when they draw a signal chain.

Related terms