Acoustic Suspension Speaker Cabinets

Have you ever wondered how Acoustic Suspension Speaker Cabinets work?

• A speaker mounted in a small box will compress the air inside when the cone moves inward
• The air then pushes on the cone harder than the air on the outside
• The speaker will expand the air in the box when it moves outward
• The outside air will be pushing harder than the inside air

By using this pressure to restore the speaker cone to neutral, a much smaller box can be used to get deep bass. The trade off is efficiency (it is lower). Acoustic suspension dominated the speaker designs of the 1960's and 1970's as big, solid, state amplifiers were being developed to provide the needed power.

The DIY Mentality

Why would you want to build your own speakers, when you can drive down to the mall, and walk out with an entire home theater speaker system in less than an hour?
There are many things in life that are worth purchasing pre-manufactured (as they are too complicated and in-depth to assemble without proper training)—speaker enclosures are not one of these things.

Speaker enclosure design isn't brain surgery, with a little skill and the right tools you can build you own in no time. If you do choose to build a speaker enclosure yourself there are many benefits:

• It's cheaper than buying a pre-manufactured speaker enclosure
• You can be sure that high-quality parts are used
• You can custom-tailor your speaker enclosure
• There's a certain satisfaction in building something yourself

Why buy a pre-made enclosure when building one is simple and less costly?

Speakers and Psychoacoustics

If you want, you can spend over $100,000 for a pair of high end stereo speakers. The question is: Do these speakers sound better than a pair that cost $5000 or $500 ?

A large part of sound is psychoacoustic (the psychology of acoustical perception). Psychoacoustics is the subjective perception of sound versus the objective measurement of that sound by specialized test equipment. By its very nature, sound and audio reproduction is subjective. In other words, don't take someone else's word that a certain high end audio speaker is the best. Listen for yourself - in your own listening room, and compare it to live, acoustic music with voice.

Distortion - The Speaker Killer

The easiest way to destroy a perfectly good speaker is to drive it into distortion. Distortion is basically when the speaker emits sounds that are not part of the program material being played through them. There are two main types of distortion: mechanical distortion (like voice coil rub) and electrical distortion (such as amplifier clipping, and ground loops).

Any amplifier asked to play at 80 to 90 % of its potential power will clip and, if given time, destroy speakers. A normal amplifier output signal looks like a sine wave (the peaks and troughs of the wave are smooth and equal). When an amplifier is driven into clipping, the peaks and troughs are chopped off creating massive current surges that feed the speakers. The sound quality of a clipped signal is noticeably worse than a 'clean' signal.

*If you can't get the volume you want from your system you either need more power or more efficient speakers.

Caring for Real-Wood Cabinets

Many high-end speakers are finished in real-wood veneer (similar to the type found on some furniture). Real wood veneer should be treated carefully as it can stain and be scratched easily.

The best way to keep your real wood veneered speakers looking new is not use them as plant stands or coasters! Water marks and other stains can be removed, but the process is a bit involved and time consuming. If you keep your speakers polished with a good old-school paste wax (like Butcher's), it will give the speakers more resistance to moisture. Small scratches can be removed with very fine steel wool, and careful application of a wood dye pen. Taking proper care of your real-wood veneered speakers can keep them looking new for a long time.

Matching Your Home Theater Speakers

When shopping for home theater speakers, it's a good idea to pick one brand, and stick to it. Ideally, your front, center, surround, and subwoofer speakers will all be from the same manufacturer, and of similar (if not identical) design. This will ensure a seamless transition from one speaker to the next as surround effects, or voices move around your virtual soundstage. The speakers will also have similar cosmetics, and will be easier to integrate into a room's decor.

Size Matters

Size matters to many people. The smaller the speaker, the easier it is to integrate into existing décor. Not everyone has a dedicated no-limit home theater to house big tower speakers and a monster subwoofer. With this in mind, most high-end speaker manufacturers offer smaller, spouse-friendly satellite / subwoofer speaker packages which give larger home theater systems a run for their money. These smaller speakers can be less sensitive to placement too, which gives you more options for locating them within a shared-space room.

Tools Of The Trade

So you've decided to try your hand at speaker enclosure design, but are unsure about which tools you will need? A modest carpentry tool kit will be a good start, but, to achieve truly professional results, you might want to look into:

• a decent table saw
• various clamps
• a router table

The table saw will ensure perfectly straight cuts (you'll be able to construct more complex, precise speaker box designs). A good selection of clamps will allow you to construct speaker cabinets with only glue, instead of screws (many audiophiles believe a glued-together speaker enclosure is better damped than one which is assembled with screws or nails). With a router table (or a common rotary tool), you'll make short work of cutting speaker mounting holes. Routers also allow you to build a speaker box with rounded edges, or dado joints. Using the perfect tools will allow you to get the job done right.

Speakers Are An Investment

There is a large contingent of audiophiles who collect vintage audio speakers and other equipment. As with cars, some good quality vintage speakers can be worth ten times their original value. The lesser brands, however, are practically worthless and best used as planters.

A good pair of speakers can last decades if they are treated well. Speakers are a lot like cars in that they have an immediate drop in value as soon as you bring them home and plug them in. Like cars, this depreciation continues to a point. If the speaker is from a reputable manufacturer, over time (10 - 30 years) that speaker will actually increase in value.

Accidents Happen

Time, water, sunlight, humidity, pets, and children can all take a toll on speakers. Ideally, the original manufacturer will be concerned about the longevity of their speakers' performance quality and agree to repair or replace damaged speakers. How long a manufacturer supports his products gives you a good indication of their concern for quality.

If you are the least bit mechanically inclined, you can perform a little home surgery and do you own speaker repair. It's next to impossible to find a 'speaker repairman' but, with a little online exploration, you can learn how to:

• replace a blown tweeter or woofer
• repair rips in paper cone speakers
• replace rotten foam or rubber surrounds
• refinish or build your own speaker cabinets

*Many companies sell speaker repair kits to handle these types of jobs and even have online tutorials to help you along the way.