Audio system controls 1 - turn on/off and adjust the sound volume; 2 - buttons for the set frequencies of radio stations 1,2,3,4, 5, 6. To save the selected radio station, press and hold the button until you hear a beep; 3 - display; 4 - switch playing tracks or search radio station frequency back; 5 - switching folders in MP3 playback mode; 6 - play/pause in CD player mode; 7 - switch playing tracks or search radio station frequency forward; 8 - Date and time settings menu; 9 - sound settings menu. By pressing, we sequentially switch the sound level adjustment modes by frequencies (low, mid and high frequencies); balance of speaker volume level - (front/rear), balance (right/left); equalizer. To change the selected parameters, use knob 13; 10 - the mode of displaying the current INFO information. Each time this button is pressed in the CD playback or file listening mode, the following information is selected: disc title, artist, title of the record, total records. In MP3 and MMA playback mode, the following information is selected: file name, title, artist, album, folder name, number of files; 11 - list of saved radio stations, when pressed for a long time, automatic tuning and saving of radio stations with the best signal level occurs on the buttons of the set frequencies 1-6; 12 - return to the previous level in menu mode (BACK); 13 - switching on, moving and selecting in MENU mode; 14 - CD eject button; 15 - list of favorite radio stations and switching between lists*; 16 - mute sound MUTE; 17 - CONFIG system settings menu; 18 - audio system folding panel latch; 19 - switching between CD player mode and AUX external multimedia device connection mode; 20 - turns on the BAND radio mode, pressing it again switches the radio frequency range between FM and AM; 21 - indicator of loaded CD.
* Depending on the configuration.
Currently, there is a wide variety of head units, ranging from simple CD players with the ability to receive radio stations of various wave ranges and play CDs and MP3 discs, to multimedia systems with liquid crystal displays, satellite navigation, TV tuner and DVD playback.
Head unit manufacturers produce their units according to standards that define dimensions, electrical connectors, wire ends and mounting methods. The width of the head unit according to the 1DIN standard should be 180 mm, the height is 50 mm. Head units made according to the 2DIN standard have the same width, and the height is 100 mm. However, car manufacturers do not always adhere to these standards, in this case, standard head units can be integrated into the dashboard, non-standard electrical connectors are used.
To install a new head unit made according to 1DIN or 2DIN standards in place of the standard one, special kits are available. Such kits include dashboard covers or frames, mounting brackets, and adapters for electrical connectors.
There are basically three types of speakers used, divided according to the frequency they reproduce: high-frequency, mid-frequency and low-frequency speakers. Depending on the configuration, cars are equipped with two high-frequency speakers located in the lower part of the front pillar trims and four mid-range speakers located one at the lower part of the front and rear doors.
For better reproduction of low frequencies, special speakers are used that operate in a narrow range of low frequencies; such speakers are called subwoofers. Subwoofers operate from additional amplifiers, for connection of which the presence of linear outputs on the head units is required. Due to their large size, subwoofers are usually installed in the luggage compartment.
When choosing acoustic systems, you need to take into account the characteristics of the head unit and the availability of space for their installation. The nominal input power of the speaker should be greater than the output power of the amplifier, but it should not be exceeded by more than 1.5-2 times.