To everyone, it would helpful to me, and maybe the group, if you folks could explain your objective, what you're actually trying to do here with multiple subs (Yes, I have read Geddes et al.). I understand that digital FIR filters will give you both flat frequency response and linear phase relative to your mains, but also, that adding subs can smooth frequency response too. Since every room is different, it would help us to understand this in practice - both objectively (with numbers e.g. dB, phase, ms ) and ultimately subjectively (what you're listening for).
-- When using FIR EQ, why would you add more subs if you already have flat frequency response and linear phase? Is there a sonic tradeoff in your opinion between more subs v. more digital EQ?
- For your subs, what amount of measurable group delay relative to your mains in ms are you targeting? What have you been able to achieve?
- At what ms level does group delay for your subs in your room become audible relative to your mains and at what frequencies?
If I'm asking the wrong questions, please enlighten me.