Sorry for the late reply due to the National Day.
Regarding your issue, the echo and a rustle may be caused by the interference, such as the engine nosie. And it also has the relation with the different phone wireless signal transmission quality.
You can turn the volume both of your phone and head unit to the middle level, and well close your windows and doors.
If you used the external mic, please not use it, this unit has the built in internal mic hole in the front of the panel.
RegardsStatistics: Posted by Jammy — Thu Oct 06, 2016 1:42 am
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