Installing and Setting Up Loudspeakers

By Michael Riggs

Your loudspeakers, and the way they are placed in the room, will have far more effect on your system’s sound than any other component. For that reason, it’s important to spend a little time at the beginning making sure they are set up optimally.

Compatibility Issues
Start by ensuring that there is no basic mismatch between the speakers and the amplifier or receiver you plan to drive them with. For example, if you have relatively low-sensitivity speakers but will sometimes want high playback levels, you will want powerful amplifiers. (Loudspeaker sensitivity is rated in decibels of sound-pressure level, or dB SPL, at a distance of 1 meter with an input of 2.83 volts, which is equivalent to 1 watt into 8 ohms. Modern loudspeakers typically have sensitivities in the range of about 90 dB SPL/1 watt/1 meter. A low sensitivity rating would be around 87 dB or less.) Most people, however, will find 50 watts per channel to be quite satisfactory and 100 watts/channel generous. Do not be overly concerned about actual power ratings on loudspeakers. Usually these are meant to give a rough indication of how much power a speaker can handle without being damaged. In practice, however, so many variables are involved that it is impossible to come up with a single number that is valid under all, or even most, circumstances. A more likely source of trouble is in the realm of impedance. If your speakers’ impedances are lower than your amplifier or receiver is designed to handle comfortably, you may find the latter distorting, overheating, or shutting down when stressed. Speakers with rated impedances of 6 ohms or higher will usually work fine with any decent modern amplifier or receiver (even those that say on the back to use only speakers rated 8 ohms or greater). But if you have 4-ohm speakers, make sure your amplifier or receiver has high current capability and is rated to handle 4-ohm loads. A 4-ohm power specification is a good indication of this.

Terminals and Cables
Your receiver or amplifier will have at least one or two sets of relatively large terminals that are designed to accept speaker wire. Wire clips accept bare wire or pin connectors. Better models usually have binding posts for at least the front left and right speakers. Binding posts normally accept bare wire, pins, banana plugs, and spade lugs (which resemble hooks), though some omit support for one or the other of the last two. Bare wire and spade lugs provide the securest connections, because they have the large contact areas and can be clamped down tightly. Snugly fitted banana plugs are almost as secure, however, and much more convenient when you need to disconnect and reconnect for any reason. (If the binding posts for the positive and negative sides of each speaker connection are spaced _ inch apart, you can use double banana plugs, which make life even easier.) Wire clips make decent connections but are neither as convenient as bananas nor as secure as bare wire or spade lugs. Although there is a thriving market in premium speaker cable, there is no real technical or sonic imperative for using wire of unusual construction or exorbitant price. Ordinary stranded copper wire (lamp or zip cord) is perfectly satisfactory provided that it is not too skinny. (The thicker the wire–which corresponds to lower gauge number–the less its resistance to the passage of electricity.) The thinnest wire you should consider using is 18-gauge, but since 16-gauge costs only slightly more and is scarcely less flexible, we recommend it for everyday use. For long runs (more than 15 or 20 feet), especially to low-impedance speakers, you might consider moving up to thicker 14- or even 12-gauge cable. If you do, just make sure whatever you buy is reasonably flexible; such thick cable can be too stiff to handle easily if it isn’t braided to maximize flexibility. And if you intend to run any wire through walls, make sure it meets local electrical codes for in-wall electrical cabling. If you are making bare-wire connections or adding your own terminations (banana plugs, spade lugs, etc.), go to the hardware store and invest a few bucks in a decent wire cutter/stripper. It will resemble a pair of pliers with notches for cables of varying thickness. This will save a lot of aggravation.

Getting Started
When measuring your listening space for speaker cable, keep in mind that you're interested not in just one distance (amp to speaker), but several. That includes the distance from the amp to the floor, the distance from the point below the amp to the wall perimeter, the distance along the wall, the distance out from the wall to the speaker's base, and the distance up from the floor to the speaker. Add at least a foot to allow slack. If you are using bare wire, you might even add another six inches to allow for mistakes when stripping the ends. When you're done stripping, twist the strands together to form a compact hunk of copper that can be slotted into or wrapped around a speaker terminal. And before you connect anything, make sure your receiver or amplifier is turned off. If your amp is powerful and has just been on, unplug it for a few minutes before touching speaker connections, to give its internal power supply time to drain.

Red and Black
Speaker installation always involves matching connections. In other words, using standard color coding as an example, red always goes to red and black always goes to black. The red terminals on your speakers and amp are the positive (+), or hot, connection. The black terminals are the negative (–) or ground connection. This helpful color coding may continue on your cable if you have professionally terminated premium stuff. If you're using generic cord, with two leads grafted together, you can figure out which end goes to which by looking for a ridge or colored stripe on one side. Just adopt a convention, such as always connecting the marked conductor to the positive (+) terminals at both the amplifier and the speakers. Consistency is the key. If you wind up with some speakers connected one way and others in reverse, imaging and bass output will suffer, giving the sound a somewhat weak, disembodied character. Even more important: Make sure that no wire strands touch both the red and black terminals at either end of the connection. That will create a short circuit, which could impair performance, cause the amplifier or receiver to shut down, or even damage the amp or receiver. Active (meaning self-powered or powered) subwoofers are best hooked up using an RCA-jack subwoofer output from your preamp or receiver rather than a speaker output.

Sound is so heavily influenced by acoustics that it is best to think of the room as a component in the system. Will any set of speakers sound good in your room? Try the slap-echo test. Clap your hands around a room, first in the middle then near a wall. How much echo is there? A lot of echo will muddy the presentation by smothering direct sound with reflected sound. You can usually tame this sort of problem by adding carpeting, upholstery, or wall hangings, such as tapestries or curtains.

Speaker Placement
The least expensive and often most effective acoustic treatment is proper placement of both speakers and listener. Sound varies depending on where it is produced in relation to room boundaries (walls, floor, and ceiling). Where you place speakers in the room is as important as what speakers you buy. Front speakers usually should have their tweeters–the small drivers delivering the highest sounds–approximately at seated ear level, which in practice is similar to eye level. That is why they are usually mounted near the top of the speaker enclosure. Where the speakers should be placed in relation to walls will depend on their design. Check user manuals for any specific tips the manufacturer might provide. Except for subwoofers (see below), you will usually want to avoid placing speakers in corners, unless they are specifically designed for such positioning. Some speakers will sound bass-heavy when pushed back against a wall, whereas others will should bass-shy if moved out into the room. Experiment to see what works best for yours. Center-channel speakers in surround setups should be placed directly above or below the TV screen. Try to keep them as close as you can to the same height as the front left and right speakers. Remember that any speaker placed within a foot or so of a direct-view television set should be magnetically shielded, to prevent picture interference. Surround-channel speakers usually work best when placed somewhat above seated ear level (but not right up against the ceiling) and to the sides of the listening position. Dipole surround speakers should be directly to the sides of the listening area. Placement of front-radiating and bipole surrounds is more flexible, and you may prefer moving them slightly back of where you would put dipoles. If side-wall placement is impractical, you may find somewhat unconventional orientations rewarding. For example, if your listening position is right up against the back wall of the room, you might try putting a pair of speakers on that wall but facing up so that their output bounces off the ceiling. Whatever you do, avoid aiming the surround speakers at the listening area. You want them to produce a diffuse, enveloping sound field. It’s good for their sound to bounce around a bit before it reaches your ears. A true subwoofer–meaning one that operates only below 100 Hz or so–will be very hard to locate by ear. (Note, however, that a poorly designed subwoofer may generate higher-frequency distortion products or have inadequate crossovers that "leak" information above 100 Hz.) This nonlocalizable character of deep bass is helpful, because it means you can route low frequencies from any channel to a subwoofer anywhere in the room and still have it sound like its coming from where it ought to. So you can place the subwoofer for the smoothest, deepest bass response and the other speakers in the system for best imaging. For the subwoofer, the ideal location almost always is a corner away from any open windows or doors. You may want to experiment with placement, but use a corner as the starting point and see how close you can get to perfection just by adjusting the subwoofer’s level and crossover settings. But what about not-quite-subwoofers? There are quite a few speaker systems on the market that use very small satellite speakers coupled with a common bass module that handles all the low frequencies. In these systems, the "subwoofer" seldom cuts off below 120 Hz and may operate as high as 200 Hz. Depending on the exact design and how fussy you are, you may or may not be able to tuck the bass module out of the way in a corner. If you find male voices and such straying oddly, try putting the bass module against the front wall between the left and right front satellites. One more thing to watch out for: If your speakers have openings–vents or ports–in their backs, make sure you don’t smash them right up against a wall. The vents need at least a few inches of space to breathe.

Fine Tuning
Position your listening chair in the sweet spot, which should be an equal distance from the front left and right speakers and (in a surround system) directly in front of the center speaker. If possible, your seat should be at least a couple of feet from the wall behind you. In a stereo pair, most listeners prefer that the distance between the listener and each speaker match that between the speakers (an equilateral triangle). This provides good stereo separation, though it may leave the space between the speakers–known as the soundstage–less than solidly defined. The imaging of instruments or voices within the soundstage will come into stronger focus if the speakers are closer together (or the listener farther away). Your distance from the left and right speakers should be no greater than twice that between the speakers themselves. Start with the left and right speaker cabinets toed in so that they face the listening position. This will provide the most direct blast of sound. If the resulting sound is harsh or too bright, or if you want more than one critical listener to enjoy the music, start angling the speakers more and more toward facing straight out, until you find the optimum mix of focused and dispersed sound. You can manipulate bass by placing speakers nearer a wall (or walls). Try to get a smooth, natural sound. More bass is not always better!