The only problem is once you do this, it is no longer a uniform directivity speaker. You'll be able to hear a change as you move around the room, as the super-tweeter and horn tweeter interact differently at different angles. It might be a fun experiment for you. Try the speaker without a super-tweeter and walk around the room. See how it has the same spectral balance. Now conect the super-tweeter and listen. You'll hear the sparkle change as you move about.