Putting a speaker behind the screen is highly recommended, given you have a high quality microperf screen. All the major screen companies make them, but they all very in acoustical transparency, video quality, and price! You will have to make a choice between:
- Sacrificing good video
- Sacrificing good audio
- Getting out a loan to buy a Stewart Film Microperf
You also introduce other challenges when you goto a Microperf, such as a moire effect.
Having said all of this, there is a screen that has a popular thread in this forum talking about the Vutec SoundScreen. Its price seems to be pretty reasonable, but still more than the dalite.
If all this leads you away from a behind the screen center channel the next best place is above the screen.
hope this helps!
Austin