@gammonit_2000: BS? On whose part? Have you bothered going to The Planar Speaker Asylum and reading Wendell’s quote for yourself? If you don’t believe it, you can give Magnepan a call and ask them. I don’t know if you can get Wendell himself on the phone, but it’s worth a try. Josh has no affiliation with any maker of an OB/Dipole sub, and doesn’t own them himself. Duke of "Swarm" renown himself gave the same advice to the owner of a planar who called him for advice regarding subs to use with his speakers. Planar owners have for decades bemoaned the lack of success they have had in getting any sealed/ported/IB sub to blend seamlessly with their speakers. This is NOT a new issue!
When Wendell says only an OB/Diploe sub can be successfully mated with a planar, he’s not saying you can’t use a sealed/ported/IB sub with the LRS, only that the OB/Dipole alone will meet the most stringent definition of "successful". The reason for him saying that (he’s not alone, or the first to say it) is a technical matter, too complicated to be answered here. The info on the subject is available, for anyone willing to put in the time and effort to find it. I mean, I and other long-time planar fans have known about it for years. Finnish company Gradient made an OB/Dipole sub for both Quads, the 57 and 63, which were met with some enthusiasm. You should be able to find reviews of them in TAS, which may include the technical rational for the design's use with planar speakers.
Wendell was asked for his advice on the best sub to use with the LRS, and he gave it. If you don’t like his answer, you are free to ignore it, or even disregard it.