Home Theater Room Acoustics

Tips and Speaker Placement info

Room acoustics are critical to getting the most from your surround sound system – as is proper speaker placement within your room. Sound waves are lively by nature – they love to bounce around off various surfaces – the harder the surface, the better as far as sound waves are concerned. 

The shape of your room and the material of the surfaces and furnishings within the room are the major factors that will determine proper room acoustics. Firm, flat surfaces should be avoided if practicable – and parallel flat surfaces contribute to standing waves. A standing wave is an undesirable room acoustical artifact wherein a soundwave “build-up” develops when sound reflects from a flat surface back towards the sound source repeatedly. 

You want the sound to be absorbed, if possible, by furniture and other padded surfaces. Any extended or sizeable flat surface should have an acoustic treatment for the best results. Treatment solutions can include carpeting, acoustic tile, or even studio-quality acoustic panels. And keep in mind even the most high-dollar digital surround sound system will suffer if the speakers are not correctly placed within the room.

The best theater room dimensions

The Golden Ratio for home theater room acoustics is an ancient Greek ratio called “Phi” or “the Golden Section.” That ratio is the room width of 1.6 times the height and the length being 2.6 times the room height. This acoustic room ratio is said to have the very best acoustic properties and has been used over the centuries since early times. 

A rectangular room is the best average-shaped room for your home theater, and luckily it is the general shape of rooms in most homes. If you are designing a dedicated space, try the “Golden Ratio” for the best acoustic results. Dedicated rooms will also benefit from the insertion of columns along the sides for acoustic dampening (which can conceal side speakers in so equipped digital-surround systems). In place of columns – gathered drapes can be used to achieve nearly the same effect and add a bit of theater feel to the room. Carpet is an effective “acoustic deadener.”

Floors should be carpeted, of course. If you have hardwood floors, you will need at least area rugs. Dedicated rooms should either have fully carpeted walls or at least up to the chair-rail area (1/3 the way up the ). Suppose you are incorporating a theater in a living or family room. In that case, most homes have plaster walls that need some form of “deadening” acoustic treatment to prevent hollow or unnatural audio perception. 

Acoustical ceiling tiles are a plus, although most modern homes have plaster ceilings as well. Hopefully, you have a textured ceiling which will help a bit and should be sufficient if you have good sound wave absorption by other items in your room, such as carpeting and furniture. Anything fluffy you can add – even throw pillows on your furniture – will help deaden an acoustically overly “live” living room. Acoustic foam panels are available for those who would like a studio look but is rather pricey. 

You don’t want to make your room totally “dead” as it will sound unnatural because you are accustomed to hearing a bit of liveliness and reverberation in everyday life. It is best to prevent an overly lively room and an overly dead room – try to strike a “happy medium” between the two extremes.

Speaker placement is paramount to get the proper response and spatial sound field from your audio system. High-dollar systems and speakers will sound hardly better than the average if not correctly utilized. As also covered in overall room design.

Proper attention to speaker placement – along with your room acoustical considerations, will indeed enhance your enjoyment of your home cinema experience.

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