Radio Shack MPA 31 Owner's Manual page 6

Phasing the Spe^ricers
Proper ptia^g is important when you
use more ttian one speaker in ttie same
room or area. Out-of-phase speakers
can lose up to one-half of ttieir potential
volume, and can have a significantty de-
creased bass effect.
Most speaker terminals are cotor-coded
or have a mark that indicate ttie ter-
minal's potenty. Usually, terminals with
positive polarity are red or have a plus
symbol (+), and terminate vwth negative
polarity are black or have a minus sym-
bol (-).
Ptiasing is con-ect v^rtien you connect -F
to -F and - to -.
Detemiining Total Speaker
Impedance
Caution: A total speaker impedance
that is higher than 16 ohms or tower
than 4 ohms can damage your amplifier
or speakers.
• Speakers are connected in series
when the first ^Deaker's poative ter-
mrial is corBiected to the next speak-
er's negative terminal. Determine the
total speaker impedance of speakers
connected in series by adcBng up the
individual impedances of afl the con-
nected speakers.
For exampte, if you want to connect
two 8-ohm ^leakers in series, add 8
(ttie impedance of cme speaker) plus
8 (ttie impedance of the other speak-
er) for a total speaker impedance of
16 dims.
COM 4 0 8CJ ISO 70V
• Sprakers ere comected in parallel
v^rtien afl ther negative taminals are
connected to^tfier and afl their posi-
tive terrrwiate are connected together.
Determine the total speaker imped-
ance of speakers connected in paral-
lel by dividing the inipedance of one
speaker by the number of speakers.
Before you connect speakers to the
amplifier, you must determine the total
speaker impedance. In determining the
total speaker impedance, you must first
detemnine if your speakers are connect-
ed in series, paraUel, or a series/parallel
combinatton.