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Making sure that your audio/video system does what it’s meant to do — thirteenth in a series on the basics of audio.
At one time, it might have been reasonable to think of “a stereo” as one object, contained in a single cabinet that just had to be plugged in and turned on. Some modest units today fit that description as well, but to obtain anything more than minimal sound quality, you need a stereo system made up of separate components, usually from a variety of sources. Once you have selected your equipment, bought it, and taken it home, therefore, you will be faced with the challenge of setting it all up and making it work together.
It is possible to have your dealer put the system together for you, but that won’t help if you have to move the system later or if you make additions to it. You will understand your system much better if you roll up your sleeves and do it yourself. But that need not be difficult as long as you approach the task in an organized fashion.
To take advantage of the capabilities of even a modest system, you will have to plan it carefully and pay a great deal of attention to both the physical placement and the interconnection of the various components. When you are making your equipment purchases, bear in mind what you will eventually have to do to make the system work.
All systems require wires, for in stance, so before you leave the store make sure you have enough. Most components are supplied with the appropriate patch cords, but a few may not be, so rather than get all the boxes home and then find you have to run out and buy more wires before you can even begin, it’s a good idea to make sure they are included at the store. Coaxial cable for video signals is one sort of wire you might have to buy separately, as the lengths typically included with VCR’S are minimal.
The one thing you will definitely have to buy is speaker wire. As to the sort you should choose, the main determining factor is the wire’s thickness. Most specialty speaker cables are heavy enough to be appropriate for the longest runs (but this category definitely doesn’t include the sort of light, clear-plastic-coated wire often labeled “speaker wire”). When you buy conventional wire, however, you’ll find there is a wide choice of thicknesses. Ordinary 18-gauge lamp cord is probably adequate for short runs of, say, 15 feet or less, and few installations require anything heavier than 16-gauge. For very long runs, however, you should step up to 14- or even 12-gauge cable.
Once you have brought home every thing you need, there will be a strong temptation to rip all the boxes open immediately, pull out the components, and plug them together in some fashion just to see how they work. While this is a natural enough impulse, it’s one that should be controlled—a more methodical approach will reduce the likelihood of mistakes.
Before you proceed, look at the first few pages of the instruction book for each component for any specific directions about unpacking. When you have removed a component, put all the packing material back in the carton and save the box. If you have to send equipment in for service, or when you move to a new home, you will need the cartons. Check the back of each component, note down all the serial numbers, and put your list in a safe place.
Some components require a small amount of assembly or adjustment be fore they can be used. Most CD players, and, some cassette decks, have transit screws to keep their moving parts from rattling around during shipment, and these screws must be loosened or removed. One piece of equipment that often needs considerable assembly is a turntable: You may have to install the platter, the dust cover, the tonearm counterweight, or the cartridge headshell. Although it’s a good idea to put everything together right out of the box, the final assembly stage—balancing and adjusting the tonearm and cartridge—should be left until the turntable is in its final playing position.
A rough positioning of the components at this stage will show you what works physically. You may find that the receiver, say, looks peculiar sitting on top of the cassette deck because it’s an inch wider; or the CD player might be 3 inches deeper than the VCR and will sit on it only at an angle. It is easier to rearrange the components now, be fore they are connected together. Also keep in mind things that will make the system easier to operate after it is set up. For instance, if you intend to make a lot of audio recordings, place the cassette deck where its level meters will be easily visible. And make sure that there is a clear line of sight from your listening position to components with infrared remote controls.
A Matter of Power
Before you deal with any signal connections, you will have to decide how to get AC power to each of the components. With most systems, it is desirable to have everything operate from a single power switch, usually on the receiver. Most receivers, integrated amplifiers, and preamps have both switched and unswitched AC outlets on the back, but unless you have a very uncomplicated system, you will probably not be able to connect everything directly to these outlets. If the other components have their own outlets, you may be able to string them together in series, but make sure that the total maximum power consumption of all the components does not exceed the controlling component’s capacity. An alternative is to buy a power strip with five or six AC outlets and a master power switch.
Some equipment is intolerant of having AC power completely removed. With a videocassette recorder, for in stance, shutting off the power any where but at its own switch will disable its clock and timer and may erase any channel presets in its memory. Such components have to be powered from the unswitched outlet of your receiver or amplifier or even directly from a wall outlet.
Whatever arrangement you decide on, one thing you should avoid is a tangle of power cords behind the system. Not only do these cords have a tendency to tie themselves in knots, but there is a risk that tangles will cause audible hum. Most power cords come coiled up and held either by a plastic retainer or a twist tie of some sort; undo enough of the cord to reach to the appropriate power outlet and secure the rest with the supplied retainer. Then label each plug in case it has to be disconnected and reconnected later. In fact, all the cables that tie your system together should be labeled. Patch cords look pretty much alike, and once the system is wired up, it’s often hard to tell what leads where. You may want to change things in the future, and labels will save you a lot of trouble.
At this stage you should place each component close to its final position, but without obscuring the connections on the rear panel. Attach the speaker cables to the output terminals of the amplifier or receiver, being sure to observe any polarity markings (+ and - or red and black), and check to make sure there are no whiskers of wire protruding that might short-circuit against the chassis or the other terminal.
Next, if you’ve chosen separates instead of a receiver, connect the central audio components—the power amplifier, preamplifier, and tuner or the integrated amplifier and tuner—using the appropriately marked cords (make sure the power switches are off). When you have this nucleus assembled, perform a few simple tests to make sure it is connected properly.
Before you turn the power on, check the various controls on the receiver or preamplifier to make sure that the tape-monitor switches are off, that the tone controls are in the “flat” position, that the balance control is in the center, and that any speaker-selection switches are activated correctly for your setup. With the level controls down, turn on the power and observe whether all the appropriate pilot lights are illuminated. Select FM as a signal source and tune in a station, then turn the sound up gradually. Observe whether sound is being produced and whether it is coming out of both speakers. If there is any problem, shut the system down immediately and recheck your connections and settings.
If you’re hearing sound from both speakers, turn the balance control all the way to the left and then to the right, and note whether sound is being produced only by the appropriate speaker in each case. Next, place the speakers a few feet apart, and feed a mono signal to both of them at equal level. If the speakers are in phase (that is, if they have the correct relative polarity), the sound should appear to come from a very distinct point midway between the speakers. To exaggerate the effect, put your head directly be tween them—the sound should seem to originate right between your ears. If you are in any doubt, reverse the wires for one speaker only and repeat the test: the difference will immediately be obvious.
Once the central components and the speakers are working properly, it’s time to deal with the source components. Most of us spend a large portion of our hi-fi listening time tuned to FM, so it’s worth taking some trouble to make sure you are receiving a high-quality signal. This can be simple or difficult, but you never really know until you hook up an antenna and see what it does.
The simplest antenna is the T-shape wire dipole provided with most receivers and tuners. For many applications, particularly in cities, where you are close to the broadcasting antennas, a dipole is enough, but it has to be positioned carefully. Hook it to the 300-ohm antenna terminals on the rear panel of your receiver or tuner, and then move it about until the reception is best. It’s not a good idea to nail the dipole to the wall just yet, however, as you may well find a better position after living with it for a while.
If the dipole turns out to be clearly inadequate, an indoor tunable antenna may be the answer. The next step up is the rooftop antenna, but this may be impossible if, say, you live in an apartment building. In that case, you may have to subscribe to your cable-Tv company’s FM feed, if one is available.
When it comes to other sources, you may have to make some decisions, especially if you want to attach more than one recording device. All but the most modest of receivers and preamplifiers provide two or more tape-monitor circuits, and these are usually interconnected in some way, so this is the time to decide which recorder should be attached to which circuit. If you are planning to use your system for dubbing tapes, the choice may be critical, as many preamps and receivers allow copying from Deck A to Deck B, but not the other way around.
Setting up your tape equipment is normally straightforward, but it can be more complicated if it has to be done in conjunction with a signal processor— an equalizer, say, or a surround-sound decoder. With some receivers and amplifiers, a signal processor will have to be placed in one of the tape-monitor loops. For this reason, most such components have built-in tape-monitor circuits to replace the ones they occupy.
The remaining components, such as compact disc or videodisc players, should be much simpler to hook up because they are single-ended—they simply supply a signal to be reproduced. The only difficulty you are likely to face with this sort of equipment is if you have more of it than your preamp or receiver can accommodate. The best way to prevent this is by choosing equipment with the right number of inputs in the first place.
The Vinyl Touch
Although more and more buyers are choosing to do without vinyl capability, anyone with a collection of LP’s will undoubtedly add a turntable, and that should be set up next. Most turn tables are supplied with a tonearm already mounted, but in some very ambitious systems, tonearms are separate components. Where possible, it is advisable to have your dealer mount the arm before delivery; but if you find that you have to do it yourself, follow the instructions exactly—any shortcuts can seriously compromise performance.
It’s more probable that you will have to mount just the phono cartridge. Be very careful to observe things like overhang and positioning in the headshell, and make sure that the electrical connections are both secure and correct—most tonearm and cartridge manufacturers color-code the connections, but some don’t. If you have a modular P-mount cartridge and arm, things will be much simpler: Just plug the cartridge in and forget it.
After you have put together the turntable/arm/cartridge combination, move it to its final position and hook it up. A separate ground wire is included because the signal from a phone cartridge is extremely weak and therefore more susceptible to hum than other parts of the system. It’s a matter of insurance and is often not needed.
The Last Step
As you gradually interconnect your equipment, you will probably place the pieces in their final positions. What you should leave until last is the most critical part of the system: the speakers. The sound they will produce is as much a product of their acoustic environment as of their inherent properties, so great care must be taken to insure they are performing optimally.
Make sure the speakers are in acoustic environments that follow the manufacturer’s suggestions, if any, and that their respective placements are as similar as possible. Surfaces close to the speakers have a profound influence on the overall impression a speaker makes. It’s important that the two channels sound alike, and this is extremely hard to achieve if the room acts on them differently. So avoid putting one speaker in a corner and the other along a wall or next to a door way, for example. Be prepared to move the speakers around a bit— sometimes very slight adjustments of position can result in dramatic improvements in the sound.
NEXT: Making sure your audio system will sound as good years from now as it does today.
Source: Stereo Review (Jan. 1991) BY IAN G. MASTERS
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