Bottom line, I guess, is that you aren't likely to be disappointed with either choice. The 35Hz spec is probably a little optimistic for both sets, but that is typical of almost all manufacturers. Mine checked in at -3db at 40Hz in my room. Still, I ran the Pi-40s by themselves and never felt like I needed a sub, until I got a great deal on one. Then I found out how much really low bass info I was missing in some of the electronic music I listen to, so I added another to run stereo subs. Finally, I added a crossover to get the really low bass out of my main speakers...man, that was the ticket. It really cleaned up the output from the bass drivers in the Pi-40s. I can imagine that something like this setup might almost be a requirement with the Quads and their single mid/bass driver. You could accomplish the same thing with a single sub, provided it has two voice coils.
The size of your room might also play a part in your decision. The bigger the room, the more I would lean toward the Evo-30/40. No need to go with the Evo 40 if you are going to use a sub, though. Anyway, let me know what you decide. I'm curious to see how it works out. Hope it goes well.
The size of your room might also play a part in your decision. The bigger the room, the more I would lean toward the Evo-30/40. No need to go with the Evo 40 if you are going to use a sub, though. Anyway, let me know what you decide. I'm curious to see how it works out. Hope it goes well.