I2S (Inter-IC Sound)
I2S is the internal digital audio bus used between chips (typically between a USB receiver chip and DAC chip). Some premium DACs expose I2S over HDMI connectors as an alternative to USB or S/PDIF - claimed to reduce jitter.
I2S (Inter-IC Sound) is a serial digital audio bus standard used internally in audio devices – between USB receivers, DACs, ADCs, and DSP chips. Uses three signal lines: bit clock, word select (left/right), and serial data.
Where you encounter it
- Inside every USB DAC – XMOS chip talks to DAC chip via I2S
- Between Raspberry Pi audio boards and DAC HATs
- Exposed on premium DACs as an external I2S input (over HDMI cable) for supposedly lower jitter
External I2S in hi-fi
PS Audio, Denafrips, Holo Audio, Chord and other premium DAC brands offer HDMI-based I2S input. Requires a source with matching output (rare – some Denafrips DDCs, HQPlayer NAA). Debated benefit; measurable jitter reduction in some cases.
Not standardized
Every brand uses different HDMI pin assignment for I2S. Not plug-and-play between brands.
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