Great job on a fairly complex aspect of sound engineering. Position, imaging, timbre and dynamics are some of the primary aspects affected by group delay depending on the frequency range. Often, (e.g. Genelec’s FIR’s ) are used to reduce phase distortion, actual affecting group delay. DSP’s are sometimes used to address these sorts of issues.
I am taking a signal processing class and group delay is thrown out there without much reference. Not being a music person this actually Does put it in perspective. Thanks nerds!
I know that in ultra wideband designed equipment like AGI preamp, Spectral Audio gear, this is apparent. When a design is made to reproduce a wider bandwidth than the human ear can hear, that equipment sounds more realistic to most learned ear listeners. The reason was explained to me to the effect that because this bandwidth is so flat from subsonic to vhf frequencies and that coupled with the high rise time capabilities gave it that signature of realistic sound reproduction. That’s probably over simplified as far as an explanation goes but it sure fit for what was heard. Spectral gear was and, as far as I know, still is capable of reproducing dc to up in the megahertz range of frequencies. That coupled with a rise time specification of 1200 volts per microsecond slew rate gave their gear a transparency other manufacturers could not match. In the audio frequencies we can hear, this gear did not exhibit what is known as time smear due to the wide band design and the high slew rate. That combination of capabilities makes sense to bring that about. The higher the slew rate, the faster it reacts to changes in amplitude. The wider bandwidth attributes the time element with respect to the slew rate. Quick and accurate is the nutshell explanation. Keith Johnson is the engineer for the company. He can explain it where I lack his intellect and depth of knowledge! AGI preamp is no longer made. Maybe you know someone who has one, other than myself, that can explain it in terms you can understand. Keith is an engineer like you. You two speak the same language. George Merrill understands this also. He’s a genius, literally! You could ask him!
"Phase is just time". No... The phase that you put into the group delay expression is the phasor phase, not the phase resulting from time passing. The temporal aspects are of course related to the phase, but knowing the transfer function at a single-frequency signal is not enough to know the temporal behavior of that single-frequency signal, when looking at causal system behavior.
