[Chester]

i always try to stay under half of a wavelength of the frequency (especially in audible frequencies) and especially under one wavelength... I cannot remember where I read this but I believe I read it online. For example:my sub
@50hz - 7.8 ms
@40hz - 7.5
@30hz - 7.7
@20hz - 18.3
@15hz - 79.45** this is right around the tuning frequency of the subwofer...
@10hz - 23.3

now, since we are dealing with ms (1/1000 of a sec) we can divide 1000/(Frequency calculated for) which will give us the time of one wavelength. 1000/50= 20ms per wavelength, since my sub is at 7.8, I consider it to have a good group delay.

at 15 hz, the wavelength lasts ~67 ms, I have 79 however 1, I am not playing much content at this frequency 2, this is a tactile frequency rather than an audible one so it is not necessary to have such a low group delay (my opinion)

please remember that any filtering (EQ) will add groupdelay to the sound; if you can obtain the eq values you can punch them into winISD assuming you are using that program, and see the 'full' group delay for the entire signal path, not just the speaker (the speaker will most likely have the most group delay though) Hope this helps.

-Matt