Revox ICS 52 - Handbuch (Seite 20)

IWS + ICS Re:sound I
4
The total impedance of speakers
The total impedance when using
several speakers per channel
depends on the individual
impedances and the switching
option. The speaker switching
options are series and parallel. If the
total impedance is too low, causes
an overload of the amplifier (high
current) and causes the protective
circuit to be permanently activated. If
the total impedance is too high, the
amplifier is prevented from
damage(low current), but on the
other hand, maximum achievable
volume is very low and the speaker’s
full potential is not used.
As the impedance is the speaker’s
frequency-dependant resistor, Revox
recommends that you carry out a test
at the threshold of the permitted
speaker impedance.
Take note of the polarity of the
individual speakers with the various
switching options. The speakers should
always be of the same type, in order to
avoid variances in sound pressure and
radiation. If one or even more
speakers are connected with
reversed polarity, this results in a
significantly reduced bass
reproduction, together with an
imprecise and diffused sound
picture.
Parallel switching
Z
=
Z + Z + Z + Z
Z x Z x Z x
1 2 3 n
1 2 3 n
Z
Two speakers in parallel
fig. 1
Three speakers in parallel
fig. 2
Result fig. 1
The parallel switching of 2 speakers
is not a problem.
Result fig. 2
The parallel switching of 3 speakers
leads to a very low overall
impedance and is therefore not
recommended!