Why use I²S for a digital connection?
An I²S (Inter-IC Sound) connection can sound better because it avoids some of the timing and jitter problems that happen when you use a traditional digital audio interface like S/PDIF or AES/EBU.
What I²S actually carries
I²S isn’t just “a digital audio signal” — it’s actually a set of three (sometimes four) separate clocked lines:
• Bit Clock (BCLK) – controls the timing of each bit
• Word Clock / Left-Right Clock (LRCLK) – indicates which channel (L/R) is active
• Data (SDATA) – carries the actual audio data
• (Optionally) Master Clock (MCLK) – used by some DACs for even finer timing
Because all these clocks are separate, the DAC doesn’t need to extract timing from a data stream — it’s already perfectly synchronized to the source.
Why that matters: jitter
With S/PDIF, the clock and audio data are encoded together and sent over one line.
• The DAC must recover the clock from this mixed signal.
• That process introduces jitter — tiny timing errors in when samples are read.
• Jitter can cause subtle but audible degradation: loss of clarity, spatial depth, and definition.
I²S avoids this completely because the clock is transmitted directly and cleanly. So the DAC reads the data exactly when it should.
No protocol conversion needed
Inside every DAC chip, the incoming signal (USB, SPDIF, etc.) is eventually converted internally to I²S before the actual D/A conversion.
If you feed the DAC native I²S, you’re essentially bypassing the extra conversion and recovery circuitry, which can:
• Reduce jitter
• Shorten the signal path
• Lower noise and interference
The caveats
Compatibility issues:
• I²S isn’t a standardized external connector, so implementations differ (HDMI-style, RJ45, header pins, etc.).
• You need both devices (source & DAC) that support compatible I²S pinouts and clocks.
• Note: Shanling, Onix, and Laiv products allow you to select your choice of pinouts for I²S over HDMI, so compatibility with other products is not an issue.
Summary:
I²S is often “better” because it delivers clock and data separately and directly to the DAC chip, minimizing jitter and unnecessary conversions. It’s a purer connection — but only if the implementation is correct and both devices are compatible. To ensure a superb I²S connection, the Furutech HF-X-NCF HDMI & I2S cable is one of the best options available.
