Rear tweeter - Pros and Cons

[Sony]

I've seen a few highend models, like french manufacturer Triangle, coming up with a replicate tweeter (and sometimes midrange too) on the rear of the speaker firing to the wall.
This could really boost spaciality.

Never heard any of these, but I am tempted to try it on my speakers. It is not a difficult neither expensive transformation - new pair of tweeters, more wire, fixing the tweeters on the rear and modify the crossover.

Theorically I would expect the result to be very room dependent, including the distance from the speaker to the wall, and, therefore, likely not to result as expected in many rooms.
Another problem I see is that the perfect distance to the wall for a vented speaker with a rear port may not be the same for the rear tweeter, thus resulting in a win-lose transformation.

What can you tell me from your experience with rear tweeters? How room dependent is it? What distance from the rear wall do you recommend?

Thanks

[Salas]

I have some experience with ambient tweeter use.

I would say that if the cabinet does not cast a big aural shadow like in bulky speakers with problematic power response or fullrange speakers that may miss sparkle, then you dont need it.
In a capable dispersionwise speaker its an add on that sounds phasey to me.
I found that it helps matters and integrades better if set on top of the needy speaker in specific assymetric positions different for every speaker.
12dB reversed filters mainly worked, with some attenuation relative to the main HF units or Fullrangers.

[soongsc]

Adding an ambient tweeter might be okay of the speakers are at least 1 meter away from the walls. You want to keep the reflected wave delayed as long as possible, otherwise it will effect imaging.