I had a thought (rare) and was wondering if this would be stupid or just plain crazy, or both.
Assume for a moment that I had bought a pair of KEF Q500 floor standing speakers for about 30% off list price. They're a 2-1/2 way crossover with a Uni-Q tweeter/midrange, one 5-1/4" woofer and two "Acoustic Bass Resonator" of that same size. No ports, just the 2 passive radiators.
Now one of the weaker areas of the Q series is the rather pedestrian quality crossover. My understanding is that it's a 1st order Linkwitz-Riley design, but I know absolutely nothing about crossovers. I own the KEF R500, which is a true 3-way with the same size drivers. It has two 5-1/4" woofers and is rear ported and I like them enough that I'm not messing with those.
What if I were to buy a pair of the same woofer used in the Q500 and replace one ABR in each with an actual woofer, and also upgrade the crossover to a 4th order LR? That would leave one ABR, or I could remove it and turn that into a port.
Would this require all kinds of testing equipment that I don't have to make it work? Is the potential there for a much improved speaker, or is it a waste of time? I have no interest in starting a complete DYI build, I'm just wondering if I could swap out a passive radiator for an actual woofer, put in a better crossover and have a better speaker.
A nuts idea or not?