hello,
which controller is used in audio player work in car?

 

That depends on the brand and model of the audio player. There is no 'one-size-fits-all'.

 

ok, please list some one to search and how code is written on it.

 

MP3 player - Arduino Forum
https://forum.arduino.cc/index.php?topic=453760.0
Feb 6, 2017 - 2 posts - ‎2 authors
https://learn.sparkfun.com/tutorials/mp3-player-shield-hookup-guide-v15. I can't figure out if this is possible or if it can only play MP3s from the ...
Create MP3 player - Arduino Forum
forum.arduino.cc/index.php?topic=150033.0
Feb 20, 2013 - 8 posts - ‎2 authors
The next thing that I'd like to create is a MP3 player that streams music to my amplifier (3.5mm jack), this seems more complicated than I had ...
Arduino MP3 Player - Arduino Forum
forum.arduino.cc/index.php?topic=114704.0
Jul 17, 2012 - 8 posts - ‎3 authors
If you throw in several hundred hours of programming, and a few thousand lines of code, you get anMP3 player . For an Embedded systems ...
MP3 Music player problems - Arduino Forum
https://forum.arduino.cc/index.php?topic=295629.0
Jan 27, 2015 - 14 posts - ‎9 authors
It was written UART Control Serial MP3 Music Player Module For Arduino, so I thought there will be no problem at finding ready library and ...
DIY mp3 player - Arduino Forum
https://forum.arduino.cc/index.php?topic=65754.0

 

ok, what type of method is used to write and in hardware to build audio controller
storing so many frequency...

we can listen 20hz to 20khz
but when we speak what is range of freq.

 

Asked and answered.