Adjustment Of The Electronic Crossover; Operation Mode; Highpass Crossover Frequency Adjustment; Lowpass Crossover Frequency Adjustment - Spectron SP-A1500D Owner's Manual

ADJUSTMENT OF THE INTERNAL CROSSOVER

OPERATION MODE

Before you power up your amplifier, you must select and set the appropriate operation
mode first. The operation mode is set, depending on the speaker system connected to the
corresponding channel pair of the amplifier. For example select the highpass (HPF) setting
of the operation mode slide-switch, if the speaker system driven by the corresponding
channel pair is a component-, coaxial- or triaxial type. Or else, set the operation mode
switch to lowpass (LPF), if the channel pair is intended to drive a subwoofer system.
Highpass or lowpass filtering allows the connected loudspeakers to work in the
frequency bands they can reproduce best, reducing mechanical stress.

HIGHPASS CROSSOVER FREQUENCY ADJUSTMENT

For satellite speakers, set the operation mode slide switch to the "HPF position and
then adjust the highpass crossover frequency point, using the potentiometer „HPF", to
set a desired x-over frequency. Depending on the effective cone surface and the
power handling of the installed 'satellite' speaker system, it is recommended to set the
x-over frequency in between 50 to 150Hz. This setting must be determined by ear,
since it represents a compromise where either midbass reproduction or power handling
has to be sacrificed!
Note: If the highpass crossover frequency is set too low, the speakers will be
mechanically overdriven by low volume levels. If this frequency is adjusted at a point
too high, too much mid/bass is cut off and the music played back will sound thin.

LOWPASS CROSSOVER FREQUENCY ADJUSTMENT

Set the operation mode switch to its "LPF" position, to drive a subwoofer system. The
lowpass crossover frequency should be played by ear as well, i.e. since this crossover
frequency point is mostly a matter of personal taste and also depends on the vehicle
itself and the subwoofer connected to the amp. As a rule of thumb, settings in a range
between 60 to 90 Hz will render best sonic results. In general, setting the lowpass
crossover frequency point too low, will result in a weak and muddy sounding bass,
while setting this crossover frequency too high will result in a 'booming' bass sound
and reduced low end extension.
INPUT GAIN CONTROL ADJUSTMENT
Before you adjust the input gain level of the amp, to get the best signal to noise ratio
from your amp / headunit combination, you must set all tone controls (Bass, Mid,
Treble, Loudness etc.) and the fader on the headunit to the neutral or center positions.
Now turn all input gain controls of the installed amplifiers anti-clockwise to their
minimum positions and ALWAYS start with the channel pair, that drives the subwoofer
system (if applicable).
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