rear firing tweeters....

Remember the Bose speakers that were designed to point 8 little EQd woofers (each) at the wall with one or two pointed at the listener? People loved those things...and then Bose took the front speakers off and turned them around to sell as Pro Sound speakers. About a zillion people bought those...and for nearfield PA stuff they're not too bad with proper EQ, although I think a good 2 way horn design is better. A lot of Bozes on that bus.

The reason there are rear-firing tweeters has to do with human hearing/perceptual rules.

When the ear hears a sound, the brain makes a copy of the sound and then looks for sounds that might be similar. If it finds one, it does a comparison and looks for differences. This is part of the brain's processing to sort out where the sound is coming from.

Essentially what is happening here is the speaker designer is taking advantage of the brain's processing by providing short-delay echo information. The result is that you get improved imaging and soundstage, because the brain is better able to sort out from where the sounds appears to be coming. So its not *just* for better polar response!

With my Revel Ultima Gems, Kevin Voecks (former head of design for Snell, who designed the O.P.'s speakers, and who is now head of Revel and brought with him his rear firing tweeter design to Revel) the purpose of the rear tweeter is to add a sense of "spaciousness" or "air". If your room is excessively damped, turning up the rear will be beneficial because otherwise, your room will prevent you from hearing the "spaciousness" from the recording. It absolutely works.

On the other hand, if your room has alot of hard surfaces and is highly reflective, turning the rear tweeter to "O" or turning it off does the trick becuase no boost is needed to create the "air". The level of the front firing tweeter and rear firing tweeter can be adjusted as well. This is an outstanding option as it allows you to adjust your speakers to your room and makes the speakers adjustable to a very broad range of room configuations. All speakers should have this design IMHO.