ios - How to fix audio distortion issue in iPhone 6s/iPhone 6s -

i'm developing live streaming app. have issue audio distortion on both iphone 6s , 6s plus. know apple has changed audio hardware sample rate (to 48000hz).

i have tried following code, still audio gets distorted:

 -(void) setupaudiospeaker   {     nserror * audiosessionerror = nil;    [[avaudiosession sharedinstance] setcategory:        avaudiosessioncategoryplayback error: &audiosessionerror];    if (audiosessionerror) {        dlog(@"avaudiosession error %ld, %@",         (long)audiosessionerror.code,           audiosessionerror.localizeddescription);       }     nstimeinterval bufferduration =0.01;     [[avaudiosession sharedinstance]      setpreferrediobufferduration:bufferduration      error:&audiosessionerror];   if (audiosessionerror) {     dlog(@"error %ld, %@", (long)audiosessionerror.code,      audiosessionerror.localizeddescription);   }   double samplerate = 48000.0;   [[avaudiosession sharedinstance] setpreferredsamplerate:samplerate    error:&audiosessionerror];  if (audiosessionerror) {       dlog(@"avaudiosession error %ld, %@",     (long)audiosessionerror.code,      audiosessionerror.localizeddescription);   }   [[avaudiosession sharedinstance] setactive:yes   error:&audiosessionerror];  if (audiosessionerror) {     dlog(@"avaudiosession error %ld, %@", (long)audiosessionerror.code,      audiosessionerror.localizeddescription);   }   samplerate = [avaudiosession sharedinstance].samplerate;   bufferduration = [avaudiosession sharedinstance].iobufferduration;   dlog(@"sampe rate:%0.0fhz i/o buffer duration:%f", samplerate,    bufferduration);   }