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If you prefer not to "do it yourself," there are home theater specialist retailers who can help you choose the equipment, then install it in a way that both sounds right and complements your decor. This approach is particularly recommended if you plan an elaborate system.

The room

Amplifier power
All three front channels should have the same power if the three front speakers are identical. With a smaller center speaker, less center channel power is required. A total of one-half the power of one main front channel is usually sufficient for the surrounds. Specific power requirements depend on how loud you listen, speaker sensitivity, size of the room, and how much its furnishings "soak up" sound.

Audio/video connections
Use good-quality shielded cables, and be sure plugs are fully inserted into jacks. Follow the color code used on most connectors and cables to prevent confusion.

Speaker wiring
Prepare speaker wires by stripping their ends (A), then twisting the bared strands tightly together (B) to prevent shorts across terminals (C). Or, if speaker and amplifier/receiver terminals permit, use "banana" plugs to ensure solid connections (D).

Speaker polarity
Connect the "+" and "-" (usually red and black) terminals on each amplifier channel to the corresponding terminals on each speaker. To make this easier, speaker cable is coded with a bead or stripe down one lead's insulation, and/or different colored wires. Connected identically, all speakers will operate "in phase," with their cones moving back and forth together. "Out of phase" connections, while doing no harm, muddy spatial effects and weaken bass.

Processing enhancements
Some systems also feature "Cinema" digital signal processing (DSP) modes that simulate the acoustics of large theaters, and/or "THX(r)" processing that also strives for a more "theatrical" experience (see Glossary). These are provided as enhancements to Pro Logic decoding, not as alternatives.

Channel balance
Systems with Dolby Pro Logic decoding feature a test signal generator for balancing the channels. As the signal "travels" from channel to channel, adjust the balance controls until each channel plays at the same loudness level.

What to expect
Even though you adjust the surround channel to be as loud as the others on the test signal, you'll find that on actual program material the surround channel is usually much lower than the front. Don't be tempted to readjust the surround level; program producers use surround mostly for subtle atmospherics and ambience, and only rarely for special effects. A good surround mix doesn't call attention to itself; if it did, it would soon become distracting.

Regular stereo programming
Many regular stereo recordings contain natural ambience that a Pro Logic decoder will treat much like surround sound. Try leaving the decoder on when playing such recordings for a pleasant surround-like effect.

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