Stretching your stereo

Sunset, March, 1992 by Bill Crosby

IT MAY TAKE CRAWLING UNDER THE HOUSE, BUT YOU can turn your stereo into much more than a stack of gear and a couple of speakers cluttering up a corner of your living room. New products have come on the scene that can help you tap the potential in your existing components to send music to the far reaches of your house, and to control the system from those far reaches.

Last June, we introduced you to the idea of professionally installed, custom audio-video, with virtually invisible remote-controlled systems that can send audio and video signals to every corner of your house. The catch to the truly custom systems is their cost: most start around $5,000 and quickly shoot upward from there.

However, there are some inexpensive gizmos you can add to your existing stereo system on your own that will at least give you a taste of what custom audio can offer. Here, we describe four such do-it-yourself items: remote volume controls, infrared boosters, speaker distribution and protection systems, and in-wall speakers.

PUMP UP THE VOLUME FROM ACROSS THE HOUSE

Let's say that you want to reclaim your living room by moving your receiver, turntable, cassette deck, and compact disc player (as well as all those tapes, records, and CDs) to a den or closet, leaving just your speakers in place. But you dread having to hike across the house every time you want to adjust the volume.

A remote "in-line" volume control can provide the cure for your separation anxiety. It lets you adjust the volume in the room where you listen to music, no matter how far your speakers are from your equipment stack. To install one, you just run speaker wire from an amplifier or receiver to the volume control, and then to the speakers (the control affects only that set of speakers).

Volume controls housed in unobtrusive, freestanding boxes cost about $120; in-wall controls cost about half that. The dial on the box will give you about a 30-decibel volume control (from, say, really loud to just below normal volume or from normal volume to pretty quiet) in 10 steps of 3 decibels each. The last step cuts the volume completely.

Some audiophiles may detect a slight reduction in sound quality when an in-line volume control is attached to a pair of high-end speakers. Most of us, however, will never hear the difference.

MAKING YOUR REMOTE CONTROL MORE REMOTE

If you have a component that came with a remote control--most likely your CD player, although other new components also have remote capability--you can easily extend its sphere of influence to any room in the house. All you need is a pair of infrared "extenders," which come in the shape of pyramids, black boxes, or built-in wall plates.

You place a transmitter unit in any room where you listen to music, and a receiver unit within sight of your equipment stack. When you point your remote control at the transmitter, it converts the remote's infrared signal into a radio frequency signal (like a garage door opener) and transmits the command to the receiver, which turns the signal back into infrared and relays it to the component in the equipment stack.

Avoid placing transmitters where they would face windows, light bulbs, or fireplaces. These light and heat sources can give off enough infrared energy to block out the weaker signal from your remote control.

Infrared extenders vary in price, depending on the sophistication of the equipment. The pyramid-shaped transmitter shown on page 123 and a matching receiver cost $60 for the pair. You can buy additional transmitters for other rooms at $30 apiece.

ADDING SPEAKERS WITHOUT BLOWING YOUR RECEIVER

A look at the back of your receiver will tell you exactly how many speaker pairs you can hook up to it. It's as many as there are pairs of speaker output connectors in the back usually two, labeled A and B. What if you want to add a third, fourth, or fifth pair?

If you piggyback more than one set of wires onto one speaker output, you run the risk of blowing up your receiver. Receivers and speakers are designed to operate at a certain impedance, usually 8 or 4 ohms. Piggybacking lowers the impedance, sending a dangerously imbalanced current through the speaker lines.

A speaker distribution system installed near your receiver will take the output for one set of speakers and split it into several lines, feeding sound to as many as 12 pairs of speakers, depending on the particular component. (The $190 system shown on page 123 can handle four pairs of 8-ohm speakers.) Protection circuits keep the line signals in and out of the receiver in balance at a safe level of resistance.

Systems come in a variety of configurations, including options of manual or automatic engagement of the protection circuits. (If you frequently use just one pair of speakers, the manually engaging circuitry is preferable, as the protection circuits cut the volume output slightly when engaged.) The box we show requires no AC power connection, but it does need to be installed with its ventilation holes clear.