Adjustment Of The Internal Crossover - Spectron SPA2150 Owner's Manual

SPA2150 4150 Manual 28.11.2002 16:38 Uhr Seite 15

ADJUSTMENT OF THE INTERNAL CROSSOVER

OPERATION MODE
You must now select and set the appropriate operation mode of the electronic cros-
sover first. This setting depends on the speaker system connected to the corre-
sponding channel pair of the amplifier. For example, set the X-OVER slide switch to
highpass (HI), if the speaker system driven by the corresponding channel pair is a
component-, coaxial- or triaxial- type. Or else, set the X-OVER switch to lowpass
(LOW), if the corresponding channel pair is intended to drive a subwoofer system.
Highpass or lowpass filtering allows the connected loudspeakers to work in the fre-
quency band they can reproduce best.
HIGHPASS CROSSOVER FREQUENCY ADJUSTMENT
For satellite speakers, set the X-OVER slide switch to its "HI" position and set the
FREQUENCY slide switch to one of its three possible positions.
Depending on the effective cone surface and the power handling of the installed
'satellite' speaker system, one of the three selectable crossover frequencies will
give you a good compromise between sound quality and (mechanical) power hand-
ling. The correct frequency must be played and determined "by ear", since it repre-
sents either a sacrifice of the midbass reproduction or lower power handling. Note:
If the highpass crossover frequency point for a given satellite system is set too low,
the speakers will be overdriven mechanically by low volume levels. This means the
speakers will suffer from audible distortions, and sound harsh.
LOWPASS CROSSOVER FREQUENCY ADJUSTMENT
Set the X-OVER switch of a given channel pair to its "LOW" position, when you
intend to drive a subwoofer system.
The LOW PASS cut-off frequency point must also be played by ear, i.e. since the
lowpass crossover frequency point is mostly a matter of personal taste. As a rule of
thumb, either the 65Hz or 85Hz setting will give you best sonic results. In general,
setting the lowpass crossover frequency point too low, will result in a weak and
"muddy" sounding bass, while setting the lowpass crossover frequency too high,
will result in a 'booming' bass sound and reduced low end extension.
INPUT GAIN CONTROL ADJUSTMENT
Before you start to adjust the input gain, you MUST set all tone controls (Bass, Mid,
Treble, Loudness etc.) and the fader on the head unit to their neutral or center posi-
tions.
Now turn all input gain potentiometers of the installed amplifiers counter-clockwise
to their minimum positions and ALWAYS start with the channel pair, that drives the
subwoofer system (if applicable!).
SUBWOOFER CHANNEL
Turn up the volume control of your head-unit, to approximately 75% of full volume,
while playing a dynamic piece of music. Slowly increase the input gain of the amp
channels that drive your sub, by turning the GAIN potentiometer clockwise, until
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