The Importance of Room Acoustics

17th January 2011

Home Theatre

How Important is room acoustics?

Acoustics can be a complicated and a misunderstood aspect of home theatre design. It is a highly scientific process that can be as simple or as complex as you wish to make it.

Acoustical room tuning is just as vital to the home theatre experience as are projectors, speakers, and amplifiers.

Acoustics improves the frequency response in the room:

Home theatre sized rooms all have problems with standing wave bass resonances and sound reflections off walls, floors and ceiling surfaces. These cause undesirable peaks and dips in the overall frequency response, as well as throwing off the timbre match of the speakers relative to each other and the overall balance of bass, mid, and treble. While it is possible to address some of this with electronic equalisation, many problems with home theatres can only be solved at the acoustical level by treating the source of the problem with the right blend of absorption, diffusion, and bass control.

Acoustics improves the time response in the room:

A home theatre room with good frequency response but poor time response is still a room that sounds bad. All that reflected sound energy bouncing around the room takes time to die down; meanwhile, it’s wreaking havoc on the signal clarity, imaging and sound staging capabilities of the sound system. This cannot be fixed electronically. Sound absorption and diffusion is the solution.

Acoustics improves the sound field integration in the room:

Go into a home cinema that is not acoustically treated and you’ll probably come out talking about how good or bad the speakers sounded. Why? Because speakers in untreated rooms tend to sound like just that: speakers in a room. On the other hand, walk into an acoustically-optimised home cinema, and you’ll come out talking about how good the experience sounded. Acoustical treatments enable the speakers to work in harmony to create a seamless, 3D sound field.

Acoustics improves intelligibility in the room:

One of the many complaints people have against a cinema is poor speech intelligibility. While intelligibility is a challenge in cinemas for various reasons, it doesn’t have to be in small rooms. Acoustically treating the room reduces the amount of reflected sound that your brain must sort through in order to hear the good stuff. There are many benefits to this, such as reduced ear fatigue. The fundamental purpose of a home theatre is for enjoyment, where people can simply relax and enjoy the experience.

Acoustic sound isolation keeps good sound in and bad sound out:

There is perhaps no more iconic image of family life than parents telling kids to turn their music down. If you think a kid’s stereo is bad, try a multi-thousand-dollar home cinema sound system that is literally trying to convince you it’s blowing the hinges off the door. Acoustics is not just about improving the sound quality in the room, its equally important in keeping the tremendous amount of sound generated from leaking into the rest of the house. This is called sound isolation, and it can be a great investment for the family unity. Sound isolation has the simultaneous benefit of keeping distracting, extraneous sounds out of the cinema.

Acoustics increases a room’s comfort factor:

For a moment, let’s consider a home cinema to be just another room in the house. People want their homes to be comfortable and quiet environments where they can eat, sleep, entertain, and enjoy whatever leisure activities suit they fancy. Noise control, which is another facet of acoustics, considers the entire environment of the home cinema – or any room, for that matter – and eliminates all distracting or annoying noises. These are most often caused by things like HVAC, plumbing, and appliances; however, excessive sound reflections and echoes are also unpleasant.

Glen E. Browne