Surround sound set up for Home Theater
Big screen TVs have become so thin that their sound doesn’t fill a room and will never match the big picture. Still, it’s been my experience that people don’t think much about sound when buying a TV. They buy the biggest screen they can afford in search of a “going to the movies” experience, but ignore the importance of audio.
I believe this is because few people have heard a demonstration of home theater audio, so they don’t know what they are missing. Although they may have bought have a stereo receiver for listening to music, not many people understand how to buy a surround-sound system.
Unfortunately, few stores are equipped with a room that provides a real home theater demonstration. In my days selling electronics, we had a dedicated room. It was a great joy to watch people discover surround sound. We’d put on a movie and listen as arrows flew over our heads from one side of the room to the other. Robots crept up on us from the rear left speaker. To show the contrast of the experience, I’d turn off the surround sound and return to TV sound. Arrows whooshed but went nowhere, and the robots didn’t scare us because the sound wasn’t separated and sent out from the back of the room.
Part of what makes watching a movie at a theater so immersive is the big sound that surrounds you. It gives your brain clues to what is happening onscreen by directing the sound at you from all corners of the theater. It’s part of what sets the mood and tells the story.
Some sound bars that mount below the TV can create a virtual surround-sound experience. A complete, immersive experience requires an AV receiver and speakers set up around the room.
What many people still call a “stereo” (because it reminds them of the amplifier they connected to speakers for listening to music) is actually an “AV receiver” or “home theater receiver.” AV stands for audio/visual because both audio and video signals are connected to it. The audio signals are played through the speakers and the video is sent on to the TV via an HDMI cable. Most devices—DVD or Blu-ray players, high-definition cable boxes, video game consoles, media players—can connect to an AV receiver using one HDMI cable for both audio and video. Because the AV receiver is sending the picture to the TV, you choose whether to watch your cable box, media player, etc., by switching to that device’s input on the AV receiver.
The difference between stereo and surround-sound is the sound format. Stereo sound is split into two channels that come out of two speakers. Digital surround sound may be separated into as many as nine speakers. There are six speakers that make up “5.1 surround sound.” The left and right front speakers are placed equidistant from the sides of the TV, and a center channel speaker is placed above or below the TV. Left and right rear speakers are placed slightly behind you, about ear level (if possible). With “7.1 surround sound,” two more speakers are placed directly behind you, and between the left and right rear speakers. More speakers give you a better placement of sound in the room, and continuity as sound travels from speaker to speaker.
The “.1” is the subwoofer
The sixth speaker in 5.1 surround-sound is a low-effects channel (LFE) that only plays the low, rumbling bass using one big woofer speaker. Because it can’t play a full range of sound–it doesn’t reproduce sound effects, music or dialog–it is relegated the “.1″ portion in “5.1” or “7.1” surround-sound. It can be placed anywhere in the room as low bass fills the room and is non-directional. Just be sure not to place it too close to anything that may rattle when it rumbles.
The movie that is being played must be encoded with 5.1 or 7.1 surround-sound in order for the sound to be properly separated to each channel (speaker). Increasingly, online streaming services like Netflix, Amazon Instant Video, Google Play and others have 5.1 stereo. Vudu’s HDX format will include 7.1 surround-sound when a movie is so formatted.
While surround-sound speakers placed around the room provide the most immersive experience, there are also sound bars that can bounce sound around the room for a simulated surround experience. I’ll cover that in my next blog.