A measure of how much a system's output lags behind the input, frequency by frequency — high group delay can make bass sound smeared or detached from the beat.
Group delay describes timing: how long a given frequency takes to fully emerge from a speaker relative to the original signal. Some delay is unavoidable in any real-world driver or filter, but excessive group delay — especially in the bass region — can make low notes sound loose, smeared, or out of sync with the rest of the music.
Group delay tends to rise sharply near the tuning frequency of a ported enclosure or near a steep crossover filter's cutoff point. A flat frequency response with poor group delay can still sound “off”, which is why measurement software reports both.
| Context | Typical Home Audio | Typical Car Audio |
|---|---|---|
| Generally inaudible | < 1.5 cycles | < 1.5 cycles |
| Often audible | > 3 cycles at bass frequencies | > 3 cycles at bass frequencies |
