>There seems to be a lot of bookshelf sized speakers which all seem to provide far better performance as a stand mount
>What mid -high end speakers provide the imaging openess etc on a bookshelf ?
None, the problem being that even mid range wavelengths are acoustically large compared to the baffle dimensions so they go around the speaker, bounce off the wall, and arrive at your ears soon enough to be confused with the direct sound.
There are exactly two reasonable speaker placements:
1. A reasonable distance from the wall behind them. The greater of 4' and half the distance to the listener is probably a good start pushing the reflections off the front wall out 7ms and making them 6dB down from the direct sound. 3' isn't as good, 5' is better.
2. In the surface. There's no separate reflection from the direct sound to confuse with it. There's no diffraction offf the speaker baffle. In-wall speakers have the potential for superior sound in all areas except sound stage depth which seems to require some reflections to come from behind the speakers.
A wider speaker which tapers towards the wall built for on-wall placement would fit category #2.
If you're stuck with the placement, speakers not designed to go there are going to give your singers chest colds when the reflections add in-phase to the direct sound.
Your best bet is to pick speakers designed for the placement. This isn't necessarily a bad thing because you can pickup 3-5dB more efficiency, output at a given distortion level, and head room. Jim Salk (salksound.com) sells his HTS MTM and MT configurations with cross-over options for on-wall and in-wall use. Revel has some speakers with a boundary comepsnation switches. It's rare.
Next best would be to deal with the problem using electronics. A shelving high-pass filter as found on pro-sound parametric equalizers will do the trick. Home theater preamps are starting to incorporate "Audyssey" which is self-calibrating using a microphone. One Audiophile room correction solution would be the TacT RCS system. It would be better to use appropriate speakers though, because ones built for stand mounted use are throwing away amplifier output so they can pad the higher frequencies down to match the lower ones with wave lengths long enough to wrap around the baffles.
As long as you have enough clearance to avoid aerodynamic problems, moving the port from the back to the front or eliminating it isn't going to do a anything for you.
