Group delay in high order parallel

mark100 · 2024-09-11 10:36 pm

Booger weldz said:
What causes a drastic reduction in group delay by adding a 100cm pipe to an existing 300cm pipe (with exits connected)?

(pink is both, white is the plain 300cm TL)

both pipes are at velocity max for that resonace where they join? Instead of the single pipe venting onto the driver’90degrees‘ out of phase at resonance ?

Hi, when you say "high order", are your referring to the low-pass side, or the high pass side?
By 6th order, you're referring to the low-pass side, right?

When folks talk about group delay in a sub, it's almost always with regard to the high pass side.
Which is the acoustic steepness/order of the low end roll off, that's realized after all electrical filters are in place. (such as hpf etc).
And is the red group delay box in your opening post.

The blue group delay box imo, is just the result of internal box dimensions and their associated resonances.
I don't consider those to be a source of group delay, as I either use a lpf that doesn't excite the resonance frequencies, or just make sure the box doesn't have internal dimensions that pose problems.