Basement home theatres are the ultimate urban status symbol. This space has everything going for it: little natural light, away from the rest of the family’s activities, and likely a pristine space that gives you studs and cement to play with. Building a dedicated basement home theatre can raise the potential market value of your house – just like that gourmet kitchen you put in two years ago. Consider it as more than entertainment – consider it as an investment.
First Things First
What do you need to think about when you’re building a basement home theatre? First, how big will this room be? Determine the number of people you anticipate having over for movies most of the time. If this is about to become THE Sunday football destination, you want everyone to be comfortable, right?
Next, What Feeling Do You Want Your Room To Create?
In my experience, this is an excellent place to involve the ‘CFO’ of your house. Decide if this is going to be an intimate room for getting lost in movies, or the multi-purpose gaming, movies and music center of your house. (In the industry, we call this the media room. It’s just a fancy way of saying ‘rec room’ 30 years later!) Decide this with whoever will be using the room so you can create an experience everyone will enjoy.
With that vision in place, you can start laying out the budget. Here’s what I recommend:
• 35 to 40% of the equipment budget to the 5.1-channel home theatre speaker system. Upgrade to 7.1 if you want to show people you’re on the cutting edge of this technology.
• 30% to 35% for the high definition video display (rear projection, or front projector and screen, flat-panel plasma or LCD, plus associated controls)
• 20% to 30% for the electronics (AV receiver or AV processor and amplifiers, Blu-ray player)
• 5% to 10% for cables, wiring, and miscellaneous
Choose the Correct Room Shape
If possible, avoid square rooms and long narrow rectangular rooms because deep bass sound waves misbehave or “pile up” in square or extra-long rooms. They produce “standing waves,” which result in areas with bass peaks where you’ll hear way too much bass, and “nulls,” where you’ll hear virtually no deep bass. Sometimes these areas of too much or too little bass will vary every one or two feet.
Trying to fix the standing-wave problem after the fact using electronic band-aids like equalization or an AV receiver’s auto-EQ program is virtually impossible.
Instead, select a rectangular shaped room where the dimensions (length, width and height) are not evenly divisible by a common denominator. For example, don’t choose a room 24 x 16 x 8 ft.; instead lay out dimensions of 23 x 13 x 7 feet. That way, you’ll minimize standing waves.
Keep the Room Size to Practical Limits
How many viewers do you expect to have? Figure out how many seats and what sort of seating you’ll need – several rows of real theatre-type seats or a couple of couches plus some recliners? Then choose a room that accommodates the furniture and provides a reasonable viewing distance versus your preferred screen size. Note that the larger you make your home theatre, the larger the speakers and more subwoofers you’ll require, as well as having to spend more for bigger amplifiers.
Allot 50% or More of Your Budget to Speakers and Amplification
Don’t blow your home theatre budget on a super-expensive video projector, screen and furniture, leaving little for home theatre speakers and amplification. In other words, match your high-definition visual image with a similarly high-quality soundscape from a fine home theatre surround sound system, otherwise you’ll only be disappointed at the jarring disconnect of combining a brilliant picture with lousy sound. If you spend $2,500 on an HD front- or rear-projection system, then consider spending the same amount on a 5.1-channel home theatre speaker setup and another $800 to $1,400 or more (depending on the room size) on an A/V surround receiver or A/V processor and amplifiers.
Compute the Screen Size and Viewing Distance
Your seating distance versus screen size will determine your sense of picture clarity and detail as well as the quality of the viewing experience.
If you choose front projection, go to www.projectorcentral.com and use the Home Projector Calculator to figure out the desirable “throw” distance vs. zoom ranges for specific front projectors at various price points. Remember that standard DVDs are only 480i or 480p and no amount of “up-conversion” will magically turn them into high definition. They are NOT high definition, so you must have a reasonable viewing distance to get satisfying image clarity. You can sit much closer for true high definition TV images (720p, 1080i) or those from Blu-ray players (1080p), as close as twice the diagonal screen measurement. If you watch a lot of standard broadcast TV (not HD), then figure on a seating distance at least three or four times the diagonal screen measurement for acceptable image clarity.
Can You Live With Front Projection?
A big theatre-like widescreen image has terrific impact, but using a front projector requires a dark room (and I mean totally dark) or the projected image will look washed out. Ambient room light falling on the screen will cause poor blacks and loss of shadow detail. If you are willing to arrange your room so that it can be totally darkened – not too hard in most basement home theatres – then a compact DLP or LCD front projector is affordable and convenient, with quite stunning picture quality. Within limits, a zoom lens lets you adjust the image size to suit the viewing distance and fit the screen. If there is usually ambient light in the room, or you prefer to watch TV and movies with some lights on, consider a plasma or LCD TV – they offer much brighter, higher contrast images than a projector.
Remember to Include the Cost of a Screen for Front Projection
Using the wall for projection purposes is possible with some special and fairly expensive paints manufactured for the purpose, but a dedicated screen will produce much better contrast and image brightness. If you want the screen to be electrically lowered or raised out of sight, budget at least $600 for a retractable screen. Manually raised or lowered or fixed screens are significantly less costly.
Plan on Sheetrock or Wood-Paneled Walls and a Wood or Carpeted Floor
Avoid poured concrete floors and walls, which may cause boomy and exaggerated bass and degraded sound quality. If the floor is concrete, plan on covering it with a wood sub-floor and carpet to provide some absorbency. Likewise, cement-block walls should be covered with studs and sheetrock, drywall or wood panels.
Consider Your Room Décor as Acoustical Treatment
If you consider using a normal mix of absorbent and reflective surfaces–upholstered furniture, carpet or rugs, perhaps some draperies–and some variation in wall surfaces, then you shouldn’t have to budget for expensive room “treatments” or absorbers for a home theatre room, unless there are unusual factors at play (walls of glass, inflexible interior design rigidity). Bookcases or similar furniture will do nicely to prevent hard, aggressive reflections that may diminish sound quality. A room that has too many hard surfaces and is too reflective may inhibit dialog clarity and cause some occasional harshness in the treble; one that is too absorbent may diminish the natural sense of spaciousness that speakers can yield when there are some natural side-wall reflections.
Don’t Hide Floorstanding or Bookshelf Speakers Inside Custom Cabinets
Speakers already have their own enclosures (cabinets), and are carefully engineered to perform at their best in a freestanding location, unencumbered by special custom cabinets, nooks, custom shelving, or concealed in elaborately constructed cubbyholes behind special grilles. This extra cabinetry will degrade and change the neutral transparent tonal balance of the speakers. At the least, deep bass performance will be boomy or hollow-sounding, and the midrange and treble tonal balance may become noticeably nasal or muddy and congested.
Resist the Urge to Use In-Ceiling Speakers
The next time you are in a surround sound cinema, look up at the ceiling. There are no surround speakers on the ceiling. Instead, the surround speakers line each side wall of the theatre (plus a couple of extra surrounds on the rear wall).
There are several reasons for this. The first is that Dolby and dts 5.1-channel movie soundtracks are mixed with the surround speakers to each side because human hearing is extra-sensitive to sounds arriving from each side and in front of us (that’s why our external ear structures are cupped to collect and focus lateral and front-arriving sound). The effects of surround envelopment and directional cues are much more profound and convincing coming from the side. Our hearing is not as sensitive to spatial cues and sounds arriving from overhead and behind us.
If you want to duplicate the cinema experience and hear the surround soundtrack the way the director and audio engineers intended, put your surround speakers on the side and rear walls of your home cinema. Furthermore, multichannel music recordings played with surround speakers are also more convincing with side-mounted surrounds. It’s the delay of the lateral-arriving reflected sounds that tell our ears and brain the “size” of the acoustic space we are in, so placing your surround speakers to each side, above ear level about 6 feet or so off the floor will best duplicate how we hear ambience in real performance spaces.
There you have it! A few simple rules to help you make your basement home theatre.
Alan Lofft was formerly Editor-in-Chief of Sound & Vision (Canada) magazine for 13 years.