Who have the idea or experience for the sound level meter
with microcontroller?
I'd like to use the microphone to detect the sound level like a music.
Please let me know your advices.
If possible, please let me know how can I remove the noise sound
other than the music like the situation when I drive the car.
I believe you mean , how can you reduce the background noise from you automobile when you are lisening to your in car stereo.
Some work has been done to reduce background noise by monitering the sound and feeding it in to your stereo with a 180 phase reversal . I think BMW have tried this and first experiments have proved quite succesfull.
Fairly easy to try anyway.