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Problem in DM8148 EVM line out audioport

debasish saha1
Intellectual 920 points

Hello,


I am able to record sound files from line in audio port in DM8148 EVM.  When I play back those files from the line out port of the EVM , it is having some noise. The level of noise is pretty high.

But the same sound file, if I play through "HP out" audio port, then the sound is more clear.

What could be the problem in line out audio port and how to resolve that?

Regards,

Debasish

  • 0
    Intellectual 920 points

    what are the DM8148 EVM amixer or alsamixer configuration for getting noise free sound at line out audio port?

  • 0 in reply to debasish saha1
    TI__Guru**** 170625 points

    Debasish,

    Please refer to the DM814x Audio user guide:

    http://processors.wiki.ti.com/index.php/TI81XX_PSP_AUDIO_Driver_User_Guide

    We have special notes for noise handling:

    http://processors.wiki.ti.com/index.php/TI81XX_PSP_AUDIO_Driver_User_Guide#Using_line-in_input_on_the_EVM

    Make sure that the following steps have been completed with the help of appropriate amixer commands

    1. Line-in input unmuted
    2. Mic input muted
    3. Use differential configurations for LINE IN to suppress the noise

    Note:Please adjust volume level of the audio source used to ensure the capture quality. If the source signal level increased beyond a limit, some part of the input signals will get clipped and the noise will be amplified along with the input signal and will result in noisy output.

    A source volume level of 10% is advisable while using PC as the Audio source to the Line In for better Capture quality.

    Regards,
    Pavel