Sealed vs Ported Subwoofers

Bob, You are correct, sealed woofers do roll off @ 12db per octave. My fingers are faster than my head. Everything else is accurate. I have built several woofers in my time. The best we did back in my old SpeakerCraft/Marcof days was a woofer facing up in a encloser that had 4 ports also facing up, it had an identical section with a woofer firing down. The four ports on both sections were joined by PVC, so the top & bottom chambers were ported into each other. There was about a one inch gap between them. We made these to look like an end table, they had the benefits of a ported system, kinda like a passive radiator, yet still rolled @ 12db per octave. I haven't seen this done anywhere else. Ed Martin designed this and it was very good indeed.
If a driver has enough LINEAR excursion, I still prefer a sealed system, but I have zero issue sitting down to a good ported design anyday.

Thanks everyone for taking the time to reply to my post. I still have to get my head around some of the information. I'll wait until my basement is finished and I have time to enjoy my system before I make any decisions.

Cheers

Jim

Bob, You are correct, sealed woofers do roll off @ 12db per octave. My fingers are faster than my head. Everything else is accurate. I have built several woofers in my time. The best we did back in my old SpeakerCraft/Marcof days was a woofer facing up in a encloser that had 4 ports also facing up, it had an identical section with a woofer firing down. The four ports on both sections were joined by PVC, so the top & bottom chambers were ported into each other. There was about a one inch gap between them. We made these to look like an end table, they had the benefits of a ported system, kinda like a passive radiator, yet still rolled @ 12db per octave. I haven't seen this done anywhere else. Ed Martin designed this and it was very good indeed.
If a driver has enough LINEAR excursion, I still prefer a sealed system, but I have zero issue sitting down to a good ported design anyday.

IMHO, ported designs off better value, but ultimately sealed designs off better performance. I also question whether ported designs can ever be time and phase coherent.

Unsound summed it up nicely.