Archived:Full duplex with PCM16 codec produces echo on Nokia N95 with AD-54 headset (Known Issue)
Simultaneous audio playback and recording (full duplex) may result in echo and/or feedback loop when certain wired headsets are attached and audio is being streamed in uncompressed PCM16 format.
How to reproduce
The example application S60 Platform: Full-Duplex Audio Example supports four codecs: AMR, G.711, G.729, and iLBC.
With the following modifications, also support for PCM16 format can be added:
// Specify PCM16 fourCC as follows: fourCC = TFourCC(' ', 'P', '1', '6'); // Sample rate: conf.iRate = EMMFSampleRate16000Hz;
// Buffer size: const TUint KBufferLength = 0x2000;
Running full-duplex audio with this configuration works fine on most devices, but produces echo on the Nokia N95 when used with the AD-54 headset.
No solution exists.