rear firing tweeters....

The explanation I heard was to balance out the speaker's power response such that the tonal balance of the room reflected sound better matched the direct sound at the listening position. A rear firing tweeter is not the only way to achieve this goal.

I meant VR-2 my mistake and apology. It does have a volume potentiometer as mentioned above, but it's functional range is very limited and on the low side.

My speakers fire front and rear 100% of the audio frequencies...
No problem.
Magnepan 3.6s..

Your Maggies are dipoles. Not better, not worse, per se, but certainly different than a pair of tweeters separated by 12" or so and firing in or out of phase.

One nice thing about dipoles is the null at 90 degrees, which can reduce sidewall effects. Everything is a tradeoff. I just don't necessarily buy the idea that a rear-firing tweeter solves enough problems to offset those it causes, but of course, we're talking about engineering here, which is as much a balance of compromise as anything else.

Nice speakers, those Maggie 3.6!

>I have a pair of old Snells with rear firing tweeters...just curious why we don't see this configuration more today ? Phase issues? Placement problems? Engineering issues?

We're trying for uniform polar response which is already much broader than the midrange's dispersion with typical mid-bass driver sizes (5"+) and cross-over points (2.5KHz+) where the local directivity minima contrasts with the mid-range driver's increasing directivity to produce a harsh sound due to excess energy in the 2-4 KHz range.

If you have mid-range output headed out back as in a dipole having similar polar response at higher frequencies helps and a rear firing tweeter works well; although otherwise it's not a good idea.