Alpine CDA-7867, Руководство пользователя

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14
-EN
Basic Operation
Preset buttons (F1 through F6) Digital Time Correction
Adjusting the Time Correction
Time Correction:
The distance between the listener and the speakers in
a car vary widely due to the special conditions of the
mobile environment. 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, the CDA-7969/CDA-7867 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 a
step of 0.1 mS.
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.
Here we calculate the time correction value for the front
right tweeter in the diagram at the left.
Conditions:
Farthest Speaker – listening position: 2.25 m (88-9/16")
Front right tweeter – listening postion: 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 right tweeter a time
correction value of 5.1 ms makes it seem as if the distance
to the front right tweeter 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 right speaker
and the rear left speaker is 1.75 m (68-7/8").
F f
UP DN
g
Time correction eliminates the differences in the time
required for the sound to reach the listening position.
The time of the front right 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
Divid 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.
4
Press the Digital Time Correction button for at
least 2 seconds to switch to the Time Correction
adjusting mode.
5
Select a speaker to be adjusted by pressing the
Preset buttons (F1 through F6) button within
10 seconds of step 1.
F1: F/L (Front Left Speaker)
F2: F/R (Front Right Speaker)
F3: R/L (Rear Left Speaker)
F4: R/R (Rear Right Speaker)
F5: S/L (Subwoofer Left)
F6: S/R (Subwoofer Right)
6
Adjust the time correction value by pressing the
DN
g
button or the
f
UP button within 10
seconds of step 5.
To adjust the time correction value for other
speaker, repeat the steps 5 and 6.
NOTE
Up to 6 time correction settings can be stored in the
available Presets.
Refer to "Memorizing the Time Correction Setting" on
page 13.
5.1 (ms)
0.5 m
(19-11/16")
2.25 m
(88-9/16")