Alpine CDA-7893 About the Time Correction, Example 1. Listening Position Front Left Seat

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Basic Operation

BAND

Rotary encoder

T. CORR

About the 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-7995/CDA-7894/CDA-7893/CDA- 7892 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.

 

5.1ms

0.5m

 

2.25m

 

Tips

*Subwoofer speaker.

You cannot change the Time Correction value for the subwoofer, but you can set the subwoofer's apparent position to the front by adjusting the Time Correction value of the front and rear speakers.

For details, refer to the "Tips" on page 9.

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.

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Contents CDA-7995/CDA-7894 Alpine CD Changers Give You More Contents XM Radio Operation Remote Control OperationMP3 Operation InformationPrecautions Never Attempt the Following Basic Operation Audio Mute Function Setting TimeDisplaying Time Setting the Treble Control Setting the Bass ControlAdjusting the built-in Crossover Example 1. Listening Position Front Left Seat About the Time CorrectionExample 2. Listening Position All Seats Example of Steps 2 and 3 Setting Bass FocusSetting the MX Mode Time Difference TableChanging the Audio Level Display Pattern Blackout Mode On and OffQuick Searching Function CDA-7995/CDA-7894 onlyDisplaying the Title/Text About Title and TextTitling Discs/Stations Erasing Disc Title/Station TitleChanging Lighting Color Setup OperationSwitching the Tuner Mode Dimmer ControlSetting the AUX Mode V-Link Turning Mute Mode On/OffScroll Setting Sound Beep Guide FunctionSetting the Defeat of the External Input Connecting to an External AmplifierCDA-7894/CDA-7893/CDA-7892 only Demonstration Adjusting Display ContrastCDA-7995 only Manual Storing of Station Presets Manual TuningAutomatic Seek Tuning Radio OperationAutomatic Memory of Station Presets Tuning to Preset StationsOpening and Closing the Movable display CD Player OperationPlayback Fast Forward and Backward Music Sensor SkipRepeat Play Scanning Programs When a 12-disc CD Changer is connectedX. Random Play Controlling CD Changer OptionalMulti-Changer Selection Playing MP3 Files MP3 OperationPlaying MP3 Files with the CD Changer Optional Selecting Folders File SearchPlaying MP3 Data Setting the Range of MP3 File SelectionWhat is MP3? About MP3Terminology Receiving XM Channels with the XM Receiver Optional XM Radio OperationChecking the XM Radio ID Number Category Search Storing XM Channel PresetsReceiving Stored XM Channels Changing the DisplayRemote Control Operation Controls on Remote ControlBattery Replacement Information Case of DifficultyNo Magzine Antenna Specifications FM Tuner SectionInstallation and Connections PrecautionsInstallation RemovalConnections 38-ENAntenna Receptacle Power Antenna Lead Blue To prevent external noise from entering the audio systemPage Limited Warranty ALPINE-1