Background Noise Reduction in Audio signal I using high pass filter  for reduction or removal of noise of audio signal but still some noise is there in signal.i have MIC,Head Set,Bluetooth and phone are connected to controller,while talking on MIC some background is there.How to reduce the noise and is there any algorithm for it.let me know please. 

Im implementing in c code structure.

Any Algorithms ?
Depends a bit on the type of noise. If it's hum or buzz, you need to clean up your recording electronics and if push comes to shove you may be able to notch it out. 

Real acoustic background noise is difficult to remove. You may want to read up on "blind source separation". Here are a few examples http://cnl.salk.edu/~tewon/Blind/blind_audio.html