What Is Surround Sound?
As its name suggests, surround sound is a system of speakers that are connected and specifically placed around the room. They work together to allow you to hear audio — like the soundtrack of a movie or an album on CD – from different angles.
The AV Receiver Is The Control Centre
The AV (audio-video) receiver is the hub of any surround sound system. It contains the electronics for decoding the surround sound in digital TV broadcasts and on DVDs and Blu ray discs, plus provides amplifiers for the speakers.
When it comes to power, buy as many watts as you can afford. Also, make sure your AV receiver has enough connections for all the audio and video sources in your home theatre set-up, plus a few spare for future additions. A set of audio-video inputs on the front panel is handy for quickly connecting devices like digital cameras or games consoles.
How Many Speakers Do I Need?
Multi-channel surround sound systems are available in a variety of arrangements:
- 2.1-channel: With two speakers and a subwoofer, 2.1 systems are perfect if you have a small living room
- 5.1-channel: Three speakers at the front (left, centre and right), two speakers at the sides or back, plus a subwoofer
- 6.1-channel: The same configuration as 5.1-channel plus an additional speaker located behind the viewer (sometimes called the rear centre speaker)
- 7.1-channel: Three speakers at the front (left, centre and right), two speakers at the side (left and right), two speakers behind the viewer (left and right), plus a subwoofer
What Are The Different Surround Sound Formats?
Here is a list of the most popular surround sound formats and the configurations they support:
- Dolby ProLogic II: Transforms high-quality stereo sound — from sources like TV broadcasts, video games, CDs and DVDs — into 5.1 channel surround sound
- Dolby Digital: The world standard format for 5.1-channel surround sound in cinemas and at home. Dolby Digital technology is used on TV programming, DVDs, Blu-ray discs and video game consoles
- DTS: Created by Digital Theatre Systems, DTS uses less compression than Dolby Digital, which means slightly clearer sound in 5.1-channel. Most AV receivers will have both Dolby Digital and DTS. However, fewer DVDs and video games are encoded with DTS, compared with Dolby Digital
- Dolby Digital EX and DTS-ES: Both these formats cater for 6.1-channel surround sound
- Dolby TrueHD and DTS-HD Master Audio: These are multi-channel audio formats for high-definition home entertainment equipment such as Blu-ray. They're capable of 7.1 channel playback and produce studio-level audio, with zero loss in quality
Let's Talk About Speakers
Surround sound speakers are available in different types:
- Floor-standing (aka tower): As the name suggests, floor-standing speakers are placed on the ground. They provide great low-frequency response — ideal for big sound that fills the room — but also take up more space
- Bookshelf: Good for smaller spaces and can be positioned on a shelf or table, or mounted on a stand or wall. They provide good sound from a small package, but don't reproduce as much bass and may need a subwoofer
Tip: When testing out stereo speakers listen for an even, balanced sound that's clear and natural. Do the same with subwoofers using a soundtrack with deep bass.
What Is A Driver?
A speaker driver is a device that converts electrical energy into sound waves. The most common ones are:
- Woofer: The biggest driver, which produces low frequency sounds (bass)
- Tweeter: A smaller driver designed to produce the highest frequencies
- Mid-range: Produces a range of frequencies in the middle of the sound spectrum
Therefore, with that in mind, a:
- One-way speaker has just one type of driver
- Two-way speaker has a woofer and tweeter
- Three-way speaker has a woofer, tweeter and mid-range driver
The Speakers In A Surround Sound System
The speakers that make up a surround sound system include:
- Centre channel: Delivers most of the soundtrack, including special effects and dialogue
- Front (left and right): Reproduce the music, most of the special effects, and act as the stereo speakers for listening to music
- Surround (side and rear): Put you in the middle of the action by producing atmospheric sounds — like rain drops — and deliver directional effects, such as a car driving by
- Subwoofer: Provides deep bass, known as low frequency effects (LFE), like thunder or explosions
How Well Am I Connected?
Cables are used to transfer audio and video signals — in either analogue or digital form — between home theatre systems. The majority of audio-video equipment has at least one of the following connectors:
- Speaker cable: Connects speakers with audio amplifiers
- Coaxial RF: Carries video and audio signals at the same time. Higher-quality coaxial RF cables, stamped RG-6, feature lower signal loss
- Composite/RCA: Composite cables (yellow connectors) carry video signals from input devices (like DVD players) to output devices (like televisions) or an AV receiver. Composite cables often come with two RCA cables (red and white connectors), which carry audio signals in analogue format
- S-Video: Featuring round four-pin connectors, S-Video splits the video signal into two streams –- colour and brightness — and provides better colour and detail than either RF or composite cables
- Component: Also known as RGB cables (red, green and blue connectors) these carry signals from a video source to a display. The result is a truer representation of the original image than you get with RF, composite, or S-video
- HDMI: Carries high definition video and multi-channel audio soundtracks in a single cable
- USB: Provides a simple method of connecting devices –- like digital cameras, MP3 players and external hard drives — quickly and easily
When it comes to the digital audio on DVDs and CD, it makes sense to use a digital audio connection. To avoid the signal breaking up, digital cabling is best for connecting digital sources such as high definition TVs, DVD players and PVRs to the AV receiver. Plus, it carries digital audio signals in a single, tidy cable.
HDMI is the preferred cable to interconnect your new equipment. It allows minimal signal loss and distortion, and enables devices to 'talk' to each other. This means that once properly set-up you may be able to use a single remote to control your entire system.