Bass Focus - Alpine CDA-7998 Owner's Manual

Here we calculate the time correction value for the front left
speaker in the diagram at the left.
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* × 1000 = 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 the distance
to the front left speaker is the same as the distance to the
farthest speaker.
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").
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 to the
farthest speaker and the other speakers.
L = (distance to farthest speaker) – (distance to other
speakers)
3
Divide the distances calculated for the speakers by the
speed of sound (343 m/s (765 mph) at 20˚C).
These values are the time correction values for the
different speakers.

Bass Focus

The time difference between the front-rear/left-right
speakers, can be adjusted at the same time. With an
initial delay of 0.1 ms for each of the 0 to 99 steps,
audible time correction can be done.
1
Press the T.CORR button to select the Bass Focus
mode.
→ Bass Focus mode → Time correction mode
Normal mode ←
2
Press the BAND button to select the front-rear / left-
right speakers.
FL FR
→
RL RR
Front (left-right)
speakers
FL FR
←
RL RR
Rear (left-right)
speakers
3
Turn the Rotary encoder to adjust the front-rear / left-
right delay.
4
For setting another channel (speaker), repeat the steps
2 and 3.
5
After setting, press and hold the T.CORR button for
least 3 seconds to return to the normal mode.
NOTES
• Any manual time correction adjustments will also affect
corrections made in Bass Focus.
• Bass Focus mode is automatically canceled if no buttons are
pressed within 15 seconds.
FL FR
→
RL RR
Left (front-rear)
speakers
FL FR
←
RL RR
Right (front-rear)
speakers
Continued
11
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