Rockford Fosgate X4.A Mode D'emploi page 11

7. XOVER TYPE – (Used to select between Linear Phase and Non-Linear modes as well as selecting the
crossover for Front and Rear outputs)
XOVER SELECT – LINEAR PHASE or NON-LINEAR
This changes the **Phase Shift of the outputs of the amplifier.
**Phase Shift is defined as the difference in time between the input signal and the output signal. In a
normal crossover, because of the reactance of the filtering components used, phase shift of the signal
occurs. Phase shift can cause some loss of stereo imaging, as well as other sonic inaccuracies. It is possible
to digitally manipulate the signal so that no phase shift occurs, thereby preserving or maximizing the sonics
of the original signal.
In an amplifier with linear phase crossovers, there is a delay between the original signal arriving at the
amplifiers inputs, and the output signal exiting the amplifier. This delay is usually in the 50-60 millisecond
range, and can only be heard if the two signals are compared, which does not normally happen.
Connecting a second amplifier to the DSP amplifier aux outputs keeps the linear phase characteristics
intact.. Because the delay is also present on the aux outputs, both amps will be sonically synced.
However, when another non delayed amplifier is added to the system, and driven by a signal that is the
same as the input of the DSP powered amplifier, (like the summed outputs of a source unit) there can be a
noticable time difference between the two. This can sound hollow, or like an echo, and is sometimes
decribed as sounding like the music is in a tunnel.
Using the Aux Outputs eliminates the delay in the DSP powered amplifier and allows both amps to be
driven by the same signal source.
FRONT XOVER – (Front Channel Crossover Settings) {Uses same sub-menus as REAR XOVER}
REAR XOVER – (Rear Channel Crossover Settings)
(FRONT/REAR) XOVER - ALL PASS, LOW PASS, HIGH PASS or DIRECT {Default is ALL PASS}
The crossover type can be adjusted between All Pass, Low Pass, High Pass or Direct mode. All Pass or
Direct routes the full bandwidth input signal to the speaker outputs. Direct routes the input signal with
no time delay to the speaker outputs.
NOTE: The frequency set here can also used for AUX OUTPUTS, no matter how the XOVER was set.
(FRONT/REAR) XOVER FREQ (Frequency) - 50-350 (setting in Hz) {Default is 350}
Accessible only in LOW PASS and HIGH PASS modes. The crossover frequency can be adjusted
between 50-350Hz at a crossover slope of 48dB.
Example of making DSP adjustments.
This example will be showing an adjustment
to both FRONT and REAR XOVER.
NOTE: Ensure the inputs and outputs for the
crossover being adjusted (ie, Front,
Rear or both) are connected for
proper operation.
1. Press the Select or
into the menu selections.
2. Use the (up) or
scroll through the menu until "XOVER
TYPE" shows on the screen.
3. Press the Select or
into FRONT XOVER. The screen will
display "FRONT XOVER" at top and
"SET: ALL PASS" with flashing up and down arrows at the bottom.
(right) key to enter
(down) key to
(right) key to enter
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PERATION
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