Delayed echo during phone call with EC21

IoT Modules LTE Standard Module
1

I have a setup in speaker mode to make phone call with an EC-21 chip with MAX9860.

During a call the person who’s calling the EC-21 have strange delayed echoes (when the volume speaker’s high or when the mic gain is high). The echo is not pleasant to hear and is the caller’s voice with a lot of distortion.
The EC-21 user dont have any audio problem.

We use the EC-21 in a crowded environment, we have a lot of noise and we have to push the up the volume.

We tried to modify : QUAUDMOD, CLVL, QRXGAIN, QMIC, QEEC, …
It have an effect on the echo, but he dont disappear.

Any idea to solve our problem ?

Do you have documentation about the full audio-chain processing ?

2

Dear Customer,

Thank you for contacting us.

Based on your issue, it might be acoustic coupling is too high. If speaker is loud and mic is close plus the reflective environment resulting mic captures speaker output strongly. My suggestion is Increase distance between speaker and mic. Put mic opening away from speaker, avoid same enclosure cavity.

If this is not working, we may try to work on other solution.

Best regards,
Fazrul Redzuan