Here's some good info on Audio Video Receivers. And there are Sooo many different types of Audio Signals, being used these days. I pasted in the bit, that refers, to the Only type of Audio Output Signal, available on Mom's TV. It will only work with a Dolby Digital Coaxial input Surround Sound System. Or you could buy a Converter for about $50 and use an Analog Surround Sound System. Which, I'm beginning to think, would be the better way to go. Given the Prices of Sound Systems. Compared, to the Quality, Wattage and Frequency Response that is available in these units. If, a sound system doesn't go down to 40 or 45Hz, then I don't wan it. You, need this, to get a nice Bass Sound and the upper range of a system like this will be more than adequate in the Higher Ranges, as well. So, that you can hear and understand the Speaking Voices in TV Shows and Especially Movies...

Don

www.crutchfield.com

By Dave Bar

Receiver

An audio component that combines a preamplifier, amplifier, and an AM/FM tuner in a single chassis. A stereo receiver offers two channels of amplification and is primarily intended for listening to stereo music sources.

A home theater receiver is designed to deliver both music and the surround soundtracks of movies found on Blu-ray discs, DVDs, VHS tapes, and TV programs. Home theater receivers offer between five and seven channels of amplification, and usually include several types of surround decoding (such as Dolby Digital and DTS).

Digital audio inputs and outputs

A home theater receiver's optical or coaxial digital inputs accept Dolby Digital and DTS signals from digital home theater sources (such as DVD and DBS). They also accept PCM stereo audio from components with compatible output (such as CD players). Digital inputs on stereo receivers are designed for the latter use only.

A digital output lets a receiver send PCM stereo digital audio directly to digital recorders (such as CD-R). Optical digital outputs are the type most commonly found on receivers, but some models offer coaxial outputs, too.

Optical digital connections require a special type of fiber optic cable, usually with Toslink connectors. And although coaxial digital connections use standard RCA-style jacks, you'll definitely want to use a coaxial digital audio cable designed specifically for the wider frequency bandwidth of digital signals.

Dolby® Digital

The digital audio format used on the large majority of DVDs, all HDTV programs, and select satellite TV broadcasts, Dolby Digital can include from one to six channels of sound. The most common "5.1-channel" Dolby Digital has 6 discrete digital audio channels: 5 full-bandwidth channels (for front left/right, center, and surround left/right) and 1 "low frequency effects" subwoofer channel. See our surround sound format overview for more information.

Dolby® Digital EX
Dolby Digital EX is based on standard Dolby Digital technology (see above), but includes an extra "back surround" channel, making it a "6.1" format. This sixth channel is encoded as a matrixed signal within the standard left and right surround channels, and is reproduced by an additional one or two surround speakers.

You'll need a receiver with either Dolby Digital EX decoding or THX Surround EX decoding to enjoy these 6.1-channel soundtracks. The receiver must also have 6- or 7-channel power in order to drive the back surround speaker.

A Dolby Digital EX receiver can also use special processing to create 6.1-channel sound from standard 5.1-channel Dolby Digital sources. See our surround sound format overview for more information.

Dolby® Digital Plus
A newer version of Dolby Digital found on some Blu-ray high-definition video discs. Dolby Digital Plus can provide up to 7.1 discrete channels of audio. It uses less compression than Dolby Digital, delivering greater sonic detail. You'll need to connect your high-def disc player to a compatible receiver via HDMI or a multichannel analog connection to take advantage of this new format. See our surround sound format overview for more information.

Dolby® TrueHD
This surround sound format supports up to 7.1 discrete channels of high-quality audio found on some Blu-ray high-definition video discs. It uses "lossless" compression for the closest possible reproduction of the studio's original master. You'll need to connect your high-def disc player to a compatible receiver via HDMI or a multichannel analog connection to take advantage of this new format. See our surround sound format overview for more information.

Dolby Pro Logic®
Pro Logic processing can be found on all home theater receivers. It delivers 4-channel playback of Dolby Surround-encoded stereo sources (primarily VHS tapes and stereo TV broadcasts). Pro Logic includes a center channel for on-screen sound; front left and right channels for sound that moves with the action; and a limited-bandwidth mono surround channel sent to the left and right surround speakers to provide ambience and sound effects. See our surround sound format overview for more information.

Dolby Pro Logic® II
A big improvement over the original Dolby Pro Logic processing, Pro Logic II can also be found on all current home theater receivers and gives Dolby Surround-encoded sources a three-dimensionality that approaches the realism of Dolby Digital soundtracks. Pro Logic II transforms any Dolby Surround or stereo source — including music — into full 5.1-channel sound. This includes full-bandwidth stereo surround channels and a subwoofer channel. See our surround sound format overview for more information.

Dolby Pro Logic® IIx
The newest addition to the Pro Logic family was designed with today's 7-channel receivers in mind, and is available on all current models. Pro Logic IIx processing can transform Dolby Surround and stereo sources into enveloping 7.1-channel sound, complete with four full-bandwidth surround channels. (When used with 6-channel receivers, Pro Logic IIx yields 6.1 surround sound.) See our surround sound format overview for more information.

Dolby® Digital IIz
A few receivers offer a newer surround sound format called Dolby Pro Logic IIz. It adds two "height" channels to your front soundstage. These speakers typically mount on the wall above your existing front left and right speakers. A receiver with Pro Logic IIz can divvy up the front soundstage audio. It sends directional sounds — like a car racing by — to your regular front speakers, and non-directional sounds — like the roar of a crowd at a stadium — to the height channels. The result is a larger, deeper front soundstage, and a more immersive experience.

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