Whatever you do in your home theater, don't do any of this

Don't put your finger in that electrical socket!

Oh, wait, you already knew that. But here are a few other things you might not know about how not to treat your home-entertainment equipment:

• Do not buy a TV that's too big, or small, for your room. For an HDTV, determine viewing distance by multiplying the screen size, measured diagonally, by 2 ½. (Suggested viewing distance, then, for a 50-inch set, would be 10.4 feet.) For an analog TV, multiply the screen size by 3.

• Do not use the inferior composite or S-Video connections with your HDTV. (Use component video or HDMI.)

• Do not panic if your CD skips. Most likely, it's just dirty. Clean it with a lint-free cloth, wiping from the center to the edge — not in a circular motion. Some people use dish detergent or Windex, but a cloth and, if needed, a little water will work. If the disc still skips, it might have a scratch or gouge. Repair it with a Digital Innovations SkipDR Repair Kit (www.digitalinnovations.com, about $30). If all your CDs skip, it could be that your player's lens is dirty. Buy a CD cleaner with a brush attachment at your local electronics store.

• Do not turn on bright lights while watching a movie. Treat your home theater like a real movie theater. Keep it dark, with minimal lighting, so the picture really pops. Put a 7-watt nightlight in an outlet behind your TV. That should be enough. Perfectionists should try Ideal-Lume fluorescent lighting (www.cinemaquestinc.com).

• Do not play your system too loudly. Your ears won't like it; your equipment won't like it; your neighbors won't like it. If the sound is distorted, your speakers are being pushed too hard. Keep it up, and you'll fry the speakers' voice coils or blow out the amplifier.

• Do not let two speaker wires touch while the receiver is on, or you'll risk damage to the receiver. Best-case scenario: It will shut down if it has a protective circuit built in.

• Do not turn off your receiver unless the volume has been turned down all the way.

• Do not, if you've connected an audio-video receiver directly to a cable-ready TV, turn off the TV before you've turned off the receiver. (You'll hear an ugly, potentially damaging thump.) General rule: Turn off equipment in reverse order of turn-on.

• Do not group your audio connections with power cords. The power cords can carry radio-frequency interference and electromagnetic interference that hitches a ride on the interconnects and, when amplified, shows up as a hum or low-level distortion through your speakers. If you can't avoid clustering the interconnects with a power cord, try to cross the power cord with the interconnects at a 90-degree angle. Also, don't bend or twist audio cables.

• If you're putting a speaker close to the TV, make sure the speaker is magnetically shielded so it doesn't distort your set's picture. Most new speakers are shielded, but a lot of older ones are not. Check the manual.

• Do not be afraid to experiment. If you don't like the sound of your speakers, move them.

Some guidelines: Most speakers sound best when they're at least 4 feet from a side wall and 2 feet from the rear wall.

Try to get the speakers far enough off the floor so that the tweeters, the little drivers that reproduce high frequencies, align with your ears while you're seated in your favorite listening spot.

For a more intimate, detailed sound, angle in the speakers slightly so they're aimed directly at you.

For a calculated speaker placement, try the mathematical formula at Cardas Audio (www.cardas.com). Click on Insights, then Room Setup.