Radio Shack 32-2054 - Manual (Page 5)

8 9
Preparation
Placing the Amplifier
Put your amplifier to a place with adequate ventilation. Do not put it on thick
carpeting (which can restrict air flow) or near a heat source, such as a heat vent
or radiator (which can cause overheating).
Placing Speakers
Speaker placement depends on your room’s size and arrangement. We
recommend you play a wide-range recording and experiment with speaker
placement until you find the locations that result in best sound. For best results,
point the speakers toward the listeners, especially if you place the speakers
far apart so their coverage areas overlap. This prevents dead spots (areas not
covered by the speakers’ sound). Position the speakers slightly above the level
of the listeners’ heads, and be sure you have determined the correct speaker
impedance (see “Total Speaker Impedance” on Page 9).
Presetting the Controls
Before you begin making connections or using your amplifier, preset the
audio input and amplifier controls to avoid overdriving a channel or producing
extremely loud, unpleasant sound.
Presetting the Audio Input Sources
Set the audio input controls to these levels.
Audio Device Control Setting
Turntable Power Off
Tape Deck Power Off
CD Player Power Off
Amplifier Receiver
Power,
Tone
Off,
Flat
Presetting the Amplifier
After you turn on the amplifier or change the program source, set the controls
to a comfortable listening level.
Warning: To prevent possible hearing damage, set the amplifier’s controls to
the levels below.
Control Setting
Power Off
MIC 1, MIC 2, PHONO/AUX MIN
100 Hz, 1 kHz, 8 kHz 0 dB (mid-position)
MASTER VOLUME MIN
Tips for Speaker Connection
You can connect one or more 4Ÿ, 8Ÿ, or 16Ÿ speakers (not supplied) to
the amplifier, with or without transformers. To ensure equal volume from
each speaker, all the speakers connected (in series or parallel) without line
transformers should have the same impedance rating.
Total Speaker Impedance
Before you connect speakers to the amplifier, determine the speaker
connection mode: in series, in parallel, or in series and parallel combination,
then determine the total speaker impedance.
For connections in series, the total impedance is the sum of the impedances
of all the speakers connected. For example, if you connect three 4Ÿ speakers
in series, the total speaker impedance is 12Ÿ.
For connections in parallel, the total impedance is the quotient of the
impedance of one speaker divided by the number of speakers. For example, if
you connect two 8Ÿ speakers in parallel, the total speaker impedance is 4Ÿ.
Important: If you connect more than two speakers in series only or in parallel
only, be sure the total impedance does not exceed the amplifier’s maximum
impedance (16Ÿ) or fall below the minimum impedance (4Ÿ). A total speaker
impedance higher than 16Ÿ or lower than 4Ÿ can damage your amplifier.
Note: You can achieve a proper total speaker impedance with a combination
of connections in series and in parallel.
Proper Phasing
Proper phasing is important when you use more than one speaker in the same
room or area. Out-of-phase speakers can lose up to half of their potential
volume, and can have a significantly decreased bass effect. Proper phasing
occurs when speakers are set to allow sound to flow in the same direction.
About Speaker Terminals
Most speaker terminals are color-coded or have a symbol that indicates the
terminal’s polarity: red (+) = positive; black (–) = negative. Phasing is correct
when you connect this way: speaker’s negative terminal to amplifier’s COM
terminal (–), speaker’s positive terminal to amplifier’s other terminals.
Determining the Speaker Wire Length
Use the shortest length of wire possible to connect the speakers. After placing
the speakers in the desired locations, determine the wire length and choose
the appropriate gauge size.
• If wire length is 25 feet (7.6 meters) or less, wire gauge is 18.
• If wire length is over 25 feet, wire gauge is 16.
If you connect speakers without transformers, the speaker wire should be no
longer than 50 feet (15.24 meters).
Preparation Preparation