Compression Horns for Far field listening

What is a full range driver are you talking about?

If you desire the best look at Cessaro Wagner 1 one of the best sounding horns out there.

The exotic dealer in my area, Deja Vu Audio, makes custom designed systems, including systems built around full range drivers.  Quite often, the full range driver is utilized full range (i.e., no low-pass crossover network feeding the driver) with a tweeter that comes in way on top 5 to 10 kHz crossover points (typically first-order crossover and an L-pad attenuator).  I've heard several of the full range systems before and after the tweeter is added; I always prefer them with the tweeter.  The tweeter does not act so much as to add high frequency content, rather, it seems to smooth out the frequency response and make the full range driver seem less peaky and harsh.  

Now i mentioned to Richard, classical really does not have much highs,

Nope. Classical has just as much in the highs as anything else.

The tweeter does not act so much as to add high frequency content, rather, it seems to smooth out the frequency response and make the full range driver seem less peaky and harsh.  

I've seen some where the tweeters actually fired to the rear, since the main speaker (in this case a 6" PHY did quite well past 15KHz but like any FR drive is beamy. The rear firing tweeters opened up the sweet spot a bit and corrected the room energy if you are off axis.

Fostex FE208EZ is built to work with a tweeter. It doesn’t have extended HF and low-mid range dip. But I’m not sure if it can work with simple ported box.
Most of FR drivers have extended HF and as result they have recessed low-mid range. To get a balanced mid-range FR driver needs a front horn that amplifies low-mid range.