i am not sure at bass freq below 300hz you will have any special advantage of going ripole or dipole....means bass will sound same in sealed or ripole or dipole at this low...but dipole will have better room interaction of course.
I remember you said you heard OB sound of LX521 Linkwitz Riley. One of the key difference between OBs and cabinet speakers is the clear bass. Clear bass is something an OB fan dies for and so can never go back to a cabinet speaker with happy ears. Yes dipole subs do not thump chest but sounds true. Musical.
i have not read anywhere ripole offers good handling of room modes, but dipole is for sure. especially in H-frame..
Ripole is just a folded dipole and yes it has less room interaction. It has benefits of dipole and compactness of cabinet speakers.
It worked right for me as I had main speakers of much lesser SPL hence low effectiveness of Ripole didn't affect overall sound quality. Having dedicated amplifier for different drivers, I have extensive freedom as well.
i personally agree with goldy that a sealed sub can be lot more pocket friendly, small, good room interaction and nicely matches to main speakers being extremely simple to design and construct and tune! plus if u have high xmax drivers, you can add linkwitz transform to extend Fs to as close as 20hz (if enough xmax and power handling capability is available).....achieving the same with ripole or dipole could be costly affair. if ur crossing below 100hz.....then i strongly believe anything other than sealed hardly makes any sense.
I wish you could hear a Ripole. Well, Ripole is pocket friendly, more compact than a sub having same driver, has low room interaction being dipole, simpler to design than a sub (to me atleast).
Ripole Fs of a driver which is the key reason for me to go for it as I wanted to use my existing drivers with better efficiencies at lower frequencies. It's design Fs is 45 Hz. Now it is playing lower frequencies better with effective Fs being somewhere around 35 Hz. Costing is my second key measurement scale for my success.
I do not much care about frequencies lower than 40 Hz. 20 Hz sound I probably can not hear now with my age crossed 40. And I know there are not many instrument out there in music I listen which play these low frequencies.
As I said earlier as well, I listen to music, not sound reproduction. I initially check my system with sound reproduction and then enjoy music. At present I am checking my system with my ear and my set of selected sound sources in CDs and with real instruments. My goal is to get rid of laptop based cross over so that I can hear my records through this speaker system.
Very soon, I will start enjoying music more than I was with my present set of speakers.
And I am slowly getting convinced that right brain can visualize a sound so much that it actually can enjoy it same whether it listens through a tiny low quality speaker or a good quality aptly designed one. It is like a child, easy to convince.
Left mind brings in problem by defining music with frequencies.
My goal is to enjoy music through the shortest, easiest and cheapest way. Minimum qualities for enjoyment is still controlled by my left brain and soon it will be satisfied.