The system of Dolby Digital 5.1 surround sound found in movie theaters all over the world is now available to consumers in even the least expensive AV receivers. But new home theater customers are often unsure if they have everything set up correctly. How do you know if you’re actually listening to 5.1 surround sound?
If you don’t have a total of six speakers in your setup – three channels across the front (left front, center channel, right front) plus two surround speakers (one on each side of the room), and a subwoofer that provides the deep earthquake effects in blockbuster movies—then you won’t hear 5.1 surround sound. (The “5” in that phrase are the main speakers; the “.1” is the deep bass subwoofer.)
First connect your DVD or Blu-ray player with an optical or coaxial digital cable or, for newer AV receivers and players, an HDMI cable, to the AV receiver. When you play a Dolby Digital DVD, your receiver should display “Dolby Digital” on its front panel or its on-screen menu. If it doesn’t, you are not getting 5.1. (There are newer formats common to Blu-ray discs—Dolby TruHD and Dolby Digital Plus—but the default standard on all DVDs is Dolby Digital 5.1.)
All AV receivers must include some type of Dolby auto-setup system to adjust the volume levels of all five speakers and the subwoofer. Use it. The test tones for Dolby Digital, when you activate the “auto setup,” produce a hissing sound from each speaker (and a rumble from the subwoofer). If you don’t hear those, then check the speaker cable connections and the subwoofer cable. The auto-setup measures and calibrates the relative volume levels of all the speakers and the subwoofer.
When the setup is complete, you’ll hear actor’s dialogue (and vocalists with music playback) from the center channel; music and effects from the main front left and right speakers; ambience and surround effects from the surround speakers, and deep bass from the subwoofer. Be sure the subwoofer and the surrounds are not set too loud; you should just enjoy the spacious effects and deep bass, not “hear” the individual speakers. The goal is to immerse you, the viewer/listener in 5.1 surround sound spaciousness, and if you’ve done everything correctly, the experience is highly enjoyable and a huge upgrade in sound quality from the typical small speakers in all flat-screen displays.