About The Crossover; About Time Correction - Alpine iLX-507 Owner's Manual

About the Crossover

Crossover (X-Over):
This unit is equipped with an active crossover. The crossover
limits the frequencies delivered to the outputs. Each
channel is controlled independently. Thus, each speaker
pair can be driven by the frequencies for which they have
been optimally designed.
The crossover adjusts the HPF (high pass filter) or LPF (low
pass filter) of each band, and also the slope (how fast the
filter rolls off the highs or lows).
Adjustments should be made according to the
reproduction characteristics of the speakers. Depending on
the speakers, a passive network may not be necessary. If
you are unsure about this point, please consult your
authorized Alpine dealer.
Cut-off
frequency (1/3
octave steps)
HPF
Subwoofer 20 Hz -
----
(LPF)
250 Hz
Rear speaker 20 Hz -
(HPF)
250 Hz
Front
20 Hz -
speaker
250 Hz
(HPF)
Low range
Slope adjusting
Output frequency
range
Subwoofer
Slope
FLAT
Level adjusting
(0 to –
12 dB)
20 Hz
(Different from actual
display)
LPF cut-off
frequency
• HPF (high pass filter): Cuts the lower frequencies and allows
the higher frequencies to pass.
• LPF (low pass filter): Cuts the higher frequencies and allows
the lower frequencies to pass.
• Slope: The level change (in dB) for a frequency change of one
octave.
• The higher the slope value, the steeper the slope becomes.
• Adjust the slope to FLAT to bypass the HP or LP filters.
• Do not use a tweeter without the HPF on or set to a low
frequency, as it may cause damage to the speaker due to the
low frequency content.
36
-EN
Slope Level
LPF HPF LPF
0, 6, 12,
-12 to
---- 18, 24
dB/oct.
0, 6, 12,
-12 to
---- 18, 24 ----
dB/oct.
0, 6, 12,
-12 to
---- 18, 24 ----
dB/oct.
High range
Output frequency
range
Rear speaker
Front speaker
200 Hz
HPF cut-off
frequency
• Adjustment should be made according to the recommended
crossover frequency of the connected speakers. Determine the
recommended crossover frequency of the speakers. Adjusting
to a frequency range outside that recommended may cause
damage to the speakers.
For the recommended crossover frequencies of Alpine
speakers, refer to the respective Owner's Manual.
We are not responsible for damage or malfunction of speakers
caused by using the crossover outside the recommended value.

About Time Correction

The distance between the listener and the speakers in a car
vary widely due to the complex speaker placement. This
difference in the distances from the speakers to the listener
creates a shift in the sounds image and frequency
characteristics. This is caused by the time delay between the
sound reaching the listener's right versus the left ear.
To correct this, this unit is able to delay the audio signal to
the speakers closest to the listener. This effectively creates a
perception of increased distance for those speakers. The
listener can be placed at an equal distance between the left
and right speakers for optimum staging.
0 dB
The adjustment will be made for each speaker in 0.02 ms
steps.
0 dB
Example 1. Listening Position: Front
Left Seat
0 dB
Adjust the time correction level of the front left speaker to a
high value and the rear right to zero or a low value.
The sound is not balanced because the distance between
the listening position and the various speakers is different.
The difference in distance between the front left speaker
and the rear right speaker is 1.75 m (68-7/8").
Here we calculate the time correction value for the front left
speaker in the diagram on the above.
Conditions:
Farthest Speaker – listening position : 2.25 m (88-9/16")
Front left speaker – listening position : 0.5 m (19-11/16")
Calculation: L = 2.25 m – 0.5 m = 1.75 m (68-7/8")
Time correction = 1.75 ÷ 343* × 1,000 = 5.10 (ms)
∗ Speed of sound: 343 m/s (765 mph) at 20°C