Left Channel Recorded Audio File Cannot Be Heard on Wired or Bluetooth Headset.

Article ID: 99472853

Symptom

Audio files that are recorded using left channel only on the MC709x or the MC909x terminals running Windows Mobile 2005 cannot be heard on wired or Bluetooth headsets.

Facts

MC709x, MC909x,

Root Cause

This is due to a hardware design of the MC709x and the MC909x audio system, along with the way in which the headsets are wired. Symptoms exist when both of the following occur: The media/audio file is recorded with left channel only (no issues with mono right or stereo recordings). A wired headset is plugged into the terminal or a Bluetooth headset is used. A more technical explanation: Left channel of the audio system is a bi-directional channel for audio signal. During a recording the audio signal goes from the microphone thru the left channel of the audio system and into the rest of the terminal (OS and hardware). During playback, left channel audio signal goes from the system thru the left channel to the left ear piece of a headphone or, in the headset case, to the microphone. With the current audio system design, the behavior described in the issue is expected.

Resolution

Alternative solutions to this issue are:
  1. Unplug the headset and the audio will play thru the terminal speaker.
  2. Plug in a pair of headphones and the audio will play in the left speaker of the headphone.