Delay of FIR filters

FIR filters can add delay to the signal passing through it. For symetrical FIRs, the delay is half the filter length, ie for a processor working at 48kHz and with 4096 taps, the delay is 2048/48000 second, near 43ms. This is unimportant when listening to music but can be a problem if you need video synchronisation (lipsync) and is a major problem if you work for dubbing or re-recording with musicians,… In those cases, better use the minimal phase correction FIR.

Our hybrid technologie allows a non symetrical Impulse Response, with a delay that is half of the delay of a symetrical FIR. Be carefull if your system has, ie main front loudspeakers with FIR EQ (so with some delay) and a subwoofer with just parametric EQ (so without any delay), you certainly will have to add some delay to the subwoofer…You can check this with the graph p5 that shows a comparison of delays at different frequencies