Little help with REL subwoofers, please?

Thank you all. 

@sns: right on! I hope you do a follow-up post somewhere out here on your experience with the two T9s. 

@audiorusty, thank you--that may be the most accessible explanation of standing waves, and the link was very helpful. I especially appreciate your explanation of why having multiple subs with different ranges may not work as seamlessly as I had hoped.

@mijostyn, wow--I can only imagine the bass you're getting with that approach. I appreciate that you're thinking about live recordings and recreating the effect of large venues. I'm an old Deadhead and I can remember some "Phil bombs" that were unnerving in their effect. 

@northman      Which model JL Audio subwoofer did you use and how did you determine its exact position in your room? 

Not sure if the OP just ordered the T9's or not but I have tried them all in pairs and I was shocked at how much more I preferred the T5's over any of them simply because of their active down-firing and for even less money than a single T9 you can have a pair of 5's. Regardless of the stats claims, I preferred the T5's because the down-firing was just more impactful and far more effortless while the others had to work harder to produce bass impact. I just could never feel the same bass with the others. For pipe organs I would not expect the T zeros to deliver. There doesn't seem to be mention of floor material. Since my floors are hardwood, they generate their own resonance in a good way so I went with the Tzeros instead of the T5's. Despite claims of 12" subs, they are too slow for great musicality and on the rare occasions of pipe organ they may deliver but for overall music, there's just no need for all that in my experiences with music. If people are into thunderous bass for movies and stuff, I get it but for pure musicality, forget it. We have the Magnepan 1.7i's and LRS plus.

I had a JL E110. I had it dialed in pretty nicely in another room with other speakers. Moving into this smaller room and changing to the Maggies ... just didn't work. I used a CR-1; bass traps; the subwoofer crawl; and lots of different placement attempts. I thought it was a fine sub and super fun but I couldn't make it consistently work, especially for more demanding music. That's undoubtedly on me--but there comes a time to try something else. The two small RELs aren't in the same league as the JL but they sound much better! 

As is obvious, I not especially knowledgable about subwoofers or the physics of sound. Reading around the internet about Maggies and subs is dizzying. (I should add that I've owned Maggies on and off for thirty years.) I think I'm just going to have to take a leap and do some experimenting....

Classical organ music goes down to 16 Hz. That is a 32 foot organ pedal. The REL T series will not approach that type of response.