About Time Correction - Alpine iLX-407 Owner's Manual

• 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.
The adjustment will be made for each speaker in 3.4 cm
steps.
Example 1. Listening Position: Front
Left Seat
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 = 5.1 (ms)
∗ Speed of sound: 343 m/s (765 mph) at 20°C
In other words, giving the front left speaker a time
correction value of 5.1 ms makes it seem as if its distance
from the listener is the same as the distance to the farthest
speaker.
Time correction eliminates the differences in the time
required for the sound to reach the listening position.
The time of the front left speaker is corrected by 5.1 ms so
that its sound reaches the listening position at the same
time as the sound of other speakers.
Example 2. Listening Position: All
Seats
Adjust the time correction level of each speaker to almost
the same level.
1
Sit in the listening position (driver's seat, etc.)
and measure the distance (in meters)
between your head and the various speakers.
2
Calculate the difference between the distance
correction value to the farthest speaker and
the other speakers.
L = (distance to farthest speaker) – (distance to other
speakers)
These values are the time correction values for the
different speakers. Setting these values to make each
sound reach the listening position at the same time as
the sound of other speakers.
29
-EN