Explosions and big, bold sound effects certainly generate lots of excitement in action movies.  However, they are only a small part of movie sound, even in the most action-packed blockbuster. Most of the sound consists of the dialogue, all the environmental sounds that form the sonic backdrop to the scene, and the music soundtrack.  These are the sound components that bring the story to you, in all its drama, emotion and tension.  If your home theatre system doesn’t get these right, all the booms, rumbles and crashes will do nothing to create the rich, immersive movie experience we seek.  This is why there’s more to a high-end home theatre system that just loud subs, big speakers and impressive specs.

The movie experience depends critically on the dialogue.  You don't just need to hear the words, but also understand them, and pick up all the nuances of expression, intonation and rhythm that convey almost as much meaning as the words themselves.  Further, you have to do this while surrounded by all the other movie sounds.  This is the job of the centre channel, which is actually the most important channel.  Most vocal sound is in the midrange, but the consonants, which are so critical to distinguishing one word from another, have important high frequency components.  There are also important low frequency sounds that add body to the voices, and contribute to the sense of space, and to locating the voices in that space.  Therefore, you need a powerful, full-range centre channel, which produces uncoloured midrange sound, and clear, undistorted high frequencies, and has good horizontal dispersion.  This will deliver excellent dialogue with high intelligibility over a wide listening area.

The next most important channels are the left and right fronts.  These carry the soundtrack, and produce the soundstage and locate sounds within that soundstage.  Again, you’re looking for full-range, uncoloured sound that is well matched to the centre channel in frequency balance, dynamics, timing and level.  They should produce a wide, deep soundstage, and deliver their sound easily and effortlessly, with no sense of strain, whatever the reasonable level at which you choose to listen.

While the left, centre and right are the main channels, the surrounds and overheads are also important.  They carry a smaller portion of the movie’s sound, but their clarity, bandwidth and wide dispersion are important for covering the whole listening area, and transporting you into the movie's three-dimensional world.  They should be as similar as possible to the front three speakers in frequency balance and dynamics.  The spatial cues they provide can span the audible spectrum, so they should also be as full-range as possible.

The subwoofer on the LFE channel produces those booms and rumbles we mentioned earlier.  It must have the power and depth to fill the space with low frequency energy.  It must also have the speed to start, and more importantly to stop, exactly when required, to deliver the intended impact.

The quality of your speakers is critical, but they’re not the only important factor in your movie sound.  The quality and capability of your amplifier or receiver also plays a major role.  Also very important is speaker and listener positioning, the configuration and tuning of the system, and acoustic treatment, when required.  When all these factors are brought together carefully, you’re well set up for magical movie experiences, whether you watch dramas, musicals, comedies or action blockbusters.

© Wayne Butcher, 2021.  All rights reserved.