Karaoke Lewinner L-699

[jjj]

To display my art of whistling to Mp3 music I bought Lewinner699 - It's great sounding! The only problem is that its noise reduction chops the music sound at low music volume levels. As soon the Mp3 music level increases the noise reduction stops chopping the music.
It's OK for singers, yet I need to lower the Mp3 music level so that my whistling is clearly heard. Now its music level is far too high and at a low music level its noise reduction chops and cuts the sound. I contacted Lewinner technical service, but they refuse to help me, fearing I try to copy their circuit.
One way I thought of, is inserting a resistor in the music path, which decreases the music power, but then allows increasing the music volume Pot (without increasing its loudness) so that it overrides the noise reduction.

Sadly, I can only take a photo of the circuit and carefully search for the the music path emanating from the TF-card driver.
I have basic electronics hobby experience. All I need is a bit of guidance on how to search for the music path so that I don't destroy anything. I'll let you know how if I succeed. I thought of starting to search/probe with an earthed 100k resistor. Would that be OK?

 

[rjenkinsgb]

I'd start at the loudspeaker outputs and trace back through the audio amp. to see if you can find where the music and mic audio is combined.

However, it is possible that the music signal path, source selection & volume etc. are all digital and the noise reduction is internal to the DSP??

 

[Tony Stewart]

Maybe you have to modulate your volume with distance from mic with music levels