Choosing the right audio system for your needs calls for proper planning. Geeta Somkumar meets an expert who offers tips
Planning to invest in a home theatre system? Then heed this expert advice from Feroz Abubecker, area sales manager-UAE, Harman Middle East. He suggests what to look out for and how to choose the best speakers, music systems and all that goes into making home entertainment an enjoyable experience.
Home theatre systems
A home theatre system, says Abubecker, is basically a collection of speakers and audio-video components designed to reproduce a movie theatre experience in the comfort of your own home. Although the size and quality of the video screen are important issues to consider for a total viewing experience, a high-quality, ideally set up multichannel surround sound speaker system is extremely important in bringing a home theatre system to life!
Traditionally, music has been recorded in two-channel stereo mode. However, as the number of artistes releasing multichannel music DVDs and Super Audio (SA) CDs continues to grow, multichannel surround sound recordings like Dolby Digital and DTS are being embraced across the audio industry.
Multichannel sound adds a new dimension, space and a heightened sense of realism to the music experience. If recorded and engineered aesthetically, multichannel music will accurately reproduce all the direct and reflected sound of the original acoustic space. Direct sound provides localisation cues that can be realistically placed within the soundstage. Reflected sound completely envelopes the listener in the natural ambience.
What you need to enjoy home theatre and multichannel music:
* An A/V Source:
DVD-Audio/DVD-Video
SACD VCR
Satellite receiver
CD or any other audio source.
* Video:
Normal CRT TV
Rear projection TV
Plasma
LCD Projector
* Amplification:
Audio/Video receiver or surround sound preamplifier
Processor and amplifiers
For 5.1 (5 speakers, 1 base) multichannel sound, the set-up must be able to decode either Dolby Digital (Dolby Digital provides five full bandwidth channels – front left, front right, centre, surround left, and surround right – for true surround sound quality.
A low frequency effect (LFE) channel is also included. This provides the sound which will add to the special effects and action sequences in movies. This multichannel scheme is known as 5.1 channel or DTS (Digital Theatre Systems’ audio compression scheme applied to DVD and CD technology for home theatre use competing with Dolby’s AC-3 algorithm).
For 7.1 (7 speakers, 1 base) multichannel sound, the set-up must also include one or more of the following:
THX Surround EX:
Surround sound format that matrix-encodes the third surround channel into the existing left and right surround channels in a Dolby Digital signal. This channel drives a centre rear loudspeaker.
* Dolby Digital Surround EX: Surround sound format that introduces rear channels to the 5.1 playback format of Dolby Digital. This additional channel clarifies audio effects that pan from front to back and improve the realism of audio that originates from directly behind the listener.
* Dolby Prologic II: Transforms any high-quality two-channel source into five independent full-range channels – left, centre, right, left surround and right surround. Brings new life to playback of CDs, MP3s and other stereo content including surround encoded broadcast/VHS.
* DTS-ES: Adds a third surround channel to the left and right surround channels in a DTS-encoded signal. Two versions exist: straight DTS-ES matrix encodes the third surround channel into the existing left and right surround signals in a 5.1 channel source, while DTS-ES Discrete is a new format that adds a separate third surround channel.
* Neo: 6 or other 7.1 channel modes.
What is THX ?
The essence of THX is a set of guidelines that resolves problems like outside noise, inside noise (from projectors, etc), audio distortion, viewing angles, reverberation, insufficient bright images, unequalised or poor audio, etc., while watching a movie. To display the THX logo, a theatre must adopt a certain set of standards and then be certified by Lucasfilm’s THX division. The first movie to be shown in a THX-certified auditorium was the 1983 film Return of the Jedi. Now there are more than 2,000 such auditoriums around the world.
Benefits of surround sound
Just like movie theatre surround speakers, reverberant surround/rear speakers too envelop you in sound without drawing you away from enjoying the visual experience of the movie. They add size and dimension to the soundstage and ensure a seamless transition when sound and effects move from the front and centre to the side and rear speakers.
The diffused sound of these speakers puts the theatre in ‘home theatre’ and gives you a sense of ‘live’ sound.
Movie theatres use multiple arrays of surround and rear speakers to keep viewers from being distracted by the sound of any single speaker.
Conventional forward radiating speakers cannot reproduce movie theatre surround sound in your home. When they are loud enough for their sound to blend, they draw attention to themselves. But when you turn them down so they don’t distract you, they won’t blend anymore.
So, how can you hear all the glorious surround sound you’re supposed to? With reverberant sound field surround/ rear speakers placed to the sides and rear of the listener.
Evaluating your speakers
When evaluating speakers, don’t let what you see interfere with what you hear. For example, speaker size, drive size (the size of the speaker cone), design type (bass reflex vs. acoustic suspension) and price (exorbitant or affordable) are not indicators of sound quality. The only important factor is how they sound.
* Our acoustic memory is short. It’s hard to remember speaker A if you go to a different room to compare it with speaker B.
* Listen to the speakers at equal volume. Even small variations in loudness can easily be mistaken for differences in sound quality.
* Turn off any visual outputs: listen to a CD you are familiar with. Turn the video off as it will distract you. Even in a demonstration, turn it off to evaluate the speakers.
* Listen for clarity: are the speakers clean, clear and natural sounding? Are the instruments and voices intelligible?
* Listen for a “seamless” soundstage: The speakers should present a broad, cohesive image of the original sound.
* Listen to the bass: is it deep, tight and well-defined?
* Sit up straight, then slouch. If you hear a marked difference in sound quality, then the speakers have a deficiency in vertical dispersion.
* Move around: good speakers disperse sound over a whole listening area. Move around to find out what others in different listening positions would hear.
* Conclusion: take your time and trust your ears.
* Investigating the reputation of a brand name is essential. Reviews of the speakers can say a lot as well. Technology, by definition, is the practical application of knowledge. When it comes to speakers and amplifiers, always stick to brands with a reputation and which have a history in the audio industry. Never compromise or buy a poor sounding speaker just because it is available at a discount.
* Choose current amplifiers with surround modes that you can benefit from. For example, patented technologies are Harmon-Kardon, V-Max and
