azazel,

as I mentioned before I use the HTM2D (1 speaker, not 2). It is located just below the screen and tilted upwards so that it points right to my ears. I have no problems with that setup as it sounds just fine and voices etc. are not pulled downwards as you might fear.

A negative for acoustically transparent screens is (besides the price) that the pixel structure from the projected image overlays with the "holes" in the screen. This may lead to unwanted image effects/interferences.

Why don't you try placing your speakers before buying the screen. Place a single center speaker below the area where the screen would be, tilt it upwards and check how it sounds. Might save you a lot of trouble and money.

Cheers,
Thomas