Audio Wiring for your Home Theater

After setting up most of your new home theater system you are without a doubt anxious to get the DVD player going. Take a deep breath, relax, turn off any distractions and grab a cup of coffee. This is the part of installation that confuses a lot of people but we will get you through it. The complexity of the DVD player installation comes from something that is actually very good. The standards for DVD are very broad and allow systems in all price ranges to enjoy digital movies. There are several selections that have to be made for the two types of connections you will need, video and audio. Let’s look at the audio first.

At the low end is the Stereo/Surround Analog Audio. Every DVD player has two RCA outputs designed for stereo output.  Since all DVDs are MPEG-2 encoded this stereo signal can be decoded and ‘downmixed’ to Dolby Surround/ProLogic by a Prologic enabled receiver or to regular stereo if this feature is not available. This imposes the normal restrictions of Prologic including mono rear channels and no discrete sub woofer channel. If you get a DVD player before you upgrade your sound system this is the way you will have to connect the system.  These output and input jacks are color coded with white for the left channel and red for the right. (Just a note, the yellow jacks are for the video.) Even if you have one of the more advanced types of audio you should still install this option. The reason for this is simple; many DVDs do not have six-channel sound. This is especially true if you like older films and music DVDs. In these cases you can use the various emulation modes of the receiver to provide better sound. For example, I enjoy a lot of films from the 40’s and 50’s. Since many of these films on DVD are presented with mono or simple stereo sound I by-pass the digital sound and run the audio through the receiver set in ‘Theater’ mode. This mode makes the movie sound like you are an old theater. Installation of these is simple. Just match the color-coded cables with the input jacks on the receiver and the outputs on the DVD player. 

Next up in audio quality is the component analog audio. With some DVD players there are provisions for six-channel analog output provided by an internal digital/analog decoder. This method will require a receiver with six separate inputs or three sets of stereo receivers. In most cases you will not have control of the volumes for the six channels. Some set ups require a special cable with RCA connectors on one end and a DB-25 connector on the other. This may be difficult to find or replace. These methods are growing extremely rare so don’t worry about it.

Next is the true digital audio. This is the best method of getting the full sound from your DVDs. There are two kinds of connectors used to provide true six channel digital sound. The first and most common is the optical cable (Toslink). This is a thin, wire like cable that has a snap connector on each end. The jacks on the receiver or decoder and the DVD player usually have a protective cover that must be removed. If more than one optical jack is provided only uncover the one that will be in use. Keep the covers safe so you can replace it over the jack should you wish to move the unit. Try taping it to the manual. The lesser-seen connector is the SP/DIF (IEC60958) connector. This is a coaxial or fiber optic cable that can carry the six discrete channels to a decoder or receiver. In both cases the sound is the best possible and will work for all DVD players. I have had information provided to me that there is also a RCA type connector that is compliant with IEC60958 standards. I have personally not seen this one so if anyone has any additional information on this cable format please let me know. According to the DVD audio specifications, DVD players must transmit PCM, (the method is used for music CDs) and at least one MPEG-2 format usually Dolby Digital 5.1 (formerly called AC-3) or DTS (Digital Theater Sound). An increasing number of DVD players and decoders will handle both Dolby 5.1 and DTS. DTS discs require more bandwidth or space on the DVD and therefore often do not have the added features that have made DVDs so popular. Most people cannot tell the difference between the two formats in normal home conditions. Other feel that DTS provides more ‘backfill’, a greater feeling of depth from the rear speakers. The growing trend in DVDs is to provide both formats on the same disc. This takes up a lot of space and it is becoming increasingly popular to have the extras on a second disc.

To get the sound from the DVD to your speakers a couple of pieces of equipment are required. First, the DVD player has to be able to read the signal from the disc. As discussed above the main formats here are Dolby 5.1 and DTS. There are two seven channel formats out now but there are less than sixty titles that use it so lets just deal with the six channel formats for now. For DTS to be read the DVD player must be DVD certified. Now most have this ability but when you are buying your player be sure it’s in the specs.  Next you need a decoder. This translates the signal from the DVD into a digital electronic signal. There are two ways to get a decoder. First is to have it internal to the DVD player. The advantages here are one less piece of equipment to wire and take up space. You can also get a separate decoder that must be installed between the DVD player and the receiver. In this case you will need one of the two digital cables we just talked about. A single digital cable comes out of the DVD player and into the decoder. In either case you then have to get the signal from the decoder to the receiver. Usually this is done with six separate RCA cables. A home theater receiver will have a corresponding six inputs. They are labeled Front Right, Front Left, Rear Right, Rear Left, Center and Sub Woofer. At this point the back of your system will start looking like a squid family is living behind your equipment. Here is where the tip of labeling the wires comes into practice. A few moments with a label maker will save a lot of time when you have to make changes or upgrade your system. Also bring out the twist ties from the large garbage bags and bundle the cables together. Now only will it look neater and better it will be easier to trace them when the need arises. With home theaters being neat is not an obsessive-compulsive thing; it’s a survival skill.

Next time we will take a look at the connections required for DVD video. We’re getting closer to a complete system so have patience and stay calm. 

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