Introduction to Home Theater

This introductory section will help you to familiarize yourself with some basic concepts unique to multichannel surround sound receivers, which will make setup and operation smoother.

power of an explosion, adding realism and excitement to your home theater. Some people use two subwoofers, for additional power and even distribution of the sound.

Typical Home Theater System

A home theater typically includes an audio/video receiver, which controls the system; a disc player; a source component for television broadcasts (cable box, satellite dish receiver, HDTV tuner or antenna connected to the TV); a video display (television); and loudspeakers.

Multichannel Audio

The main benefit of a home theater system is the placement of loudspeakers around the room to produce “surround sound.” Surround sound immerses you in the presentation for increased realism.

The AVR 7550HD may have up to seven speakers connected directly to it (plus up to two subwoofers). Each main speaker is powered by its own amplifier channel inside the receiver. A system with more than two speakers is called a multichannel system.

•Front Left and Right – The main speakers are used as in a 2-channel system. In many surround modes, these speakers are secondary, while the main action, especially dialogue, is moved to the center speaker.

•Center – The center speaker is used for dialogue in movies and television programs, allowing the dialogue to originate near the actors’ faces, for a more natural sound.

•Surround Left and Right – The surround speakers improve directionality of ambient sounds. In addition, more loud- speakers play dynamic soundtracks without risk of overloading any one speaker.

•Surround Back Left and Right – Additional surround speakers may be placed behind the listening position, improving the precision of ambient sounds and allowing for more realistic pans.

The surround back speakers are used with surround modes designed for 7.1-channel systems, such as Dolby Digital EX, Dolby Digital Plus, Dolby TrueHD, DTS-ES (Discrete and Matrix), DTS-HD High Resolution Audio, DTS-HD Master Audio and Logic 7 (7.1 and 7.2 modes). The surround back speakers are optional, and the AVR 7550HD may be set up with a 5.1- or 5.2-channel system in the main listening area, and the surround back channels reassigned to a multizone system, where the surround back channels power loudspeakers located in another room.

Many people expect the surround speakers to play as loudly as the front speakers. Although all of the speakers in the system will be calibrated to sound equally loud at the listening position, most artists use the surround speakers for ambient effects only, and they program their materials to steer very little sound to these speakers.

•Subwoofer – A subwoofer is designed to play only the lowest frequencies (the bass). It augments smaller, limited-range satellite speakers used for the other channels. Many digital-format programs, such as movies recorded in Dolby Digital, contain a low-frequency effects (LFE) channel which is directed to the subwoofer. The LFE channel packs the punch of a rumbling train or airplane, or the

Surround Modes

There are different theories as to the best way to present surround sound and to distribute information to the speakers. A variety of algorithms have been developed in an effort to reproduce the way we hear sounds in the real world, resulting in a rich variety of options.

Several companies have taken surround sound in different directions:

•Dolby Laboratories – Dolby TrueHD, Dolby Digital Plus, Dolby Digital, Dolby Digital EX, Dolby Pro Logic II and IIx, Dolby Virtual Speaker, Dolby Headphone

•DTS – DTS-HD High Resolution Audio, DTS-HD Master Audio, DTS, DTS-ES (Discrete and Matrix), DTS Neo:6, DTS 96/24

•Harman International (the Harman Kardon parent company) – Logic 7

•Stereo Modes – Generic modes that expand upon conven- tional 2-channel stereo, including 5- and 7-channel stereo

Table A13 in the appendix contains detailed explanations of the mode groups and the mode options available within each group. Digital modes, such as Dolby Digital and DTS, are only available with specially encoded programs, such as HDTV, Blu-ray Disc media and digital cable or satellite television. Other modes may be used with digital and analog signals to create a different surround presen- tation, or to use a different number of speakers. Surround Mode selection depends upon the number of speakers in your system, the materials you are watching or listening to, and your personal tastes.