Specs & measurements

Jitter

Also called clock jitter, timing error

Jitter is timing error in a digital audio signal: the samples arrive slightly early or late relative to a perfect clock. In a DAC it adds noise and distortion sidebands, though in modern designs it usually measures far below published audibility thresholds.

With a jittery clock each sample is converted slightly early or late, so the output lands off the true waveform; the timing error here is exaggerated. In modern DACs the resulting spurs usually measure more than 110 dB below the signal.

A DAC has to convert each sample at exactly the right moment. If its clock wobbles, the output wobbles with it. Early digital audio suffered from this, and much of the folklore about cables and sources comes from that era.

Modern DACs reclock or buffer incoming data, so jitter from a USB cable or a Streamer is largely removed before conversion. Measurements show it as spikes either side of a test tone, usually more than 110 dB down. I2S enthusiasts argue it still matters; measurements rarely support an audible difference.

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