Alpine CDA-7969 Adjusting the Time Correction, Example 1. Listening Position Front Left Seat

Basic Operation

Digital Time Correction Preset buttons (F1 through F6)

DN g fUP F

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.

0.5 m	5.1 (ms)
(19-11/16")

2.25 m

(88-9/16")

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").

14-EN

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 gbutton or the fUP 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.