Bi-Wiring Theory - Tannoy KINGDOM ROYAL Manual

BI-WIRING THEORY

Loudspeakers need power signals to
produce acoustic energy when
reproducing music. The range of
electrical currents passing down the
cable from the amplifier to the
loudspeaker is very wide. In decibel
terms this is called the dynamic range.
Modern loudspeakers are capable of
resolving a very wide dynamic range
with a suitable power amplifier and
programme source. This dynamic range
of over 80dB can correspond to
voltages of between 50 Volt and 0.005
Volt at the loudspeaker terminals or
equivalent currents of between 0.0006
and 6 Amp. This is a truly wide range
of electrical signals to pass down one
cable without some interactions causing
a loss of resolution in the very small
signals.
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When electricity passes down a wire
or cable, what goes in at one end is
unfortunately different from what comes
out at the other. The degree of loss or
modification of a signal depends on the
physical characteristics of the cable
and the nature of the signal. Heavy
electrical currents flowing down thin
conductors cause heating effects. Very
high frequency signals passing along
conductors or cables of certain lengths
cause electromagnetic radiation effects
(aerials). Electrical cables are selected
for minimum loss and maximum
information resolution considering
the type of electrical signals they are
designed to carry.
A good solution to the problem is to
'bi-wire' the loudspeakers to the
amplifier. This means providing two
separate sets of cables from the power
amplifier to each loudspeaker and
dividing the electrical signals into high
current, 'slow' signals and light current,
'fast' signals. Of course, the
loudspeaker must be fitted with two
pairs of terminals to take the two sets of
cables; your Tannoy loudspeakers are
of course equipped for just this type of
connection.