The bottom speaker dont work after changing housing

Hello,

I hope you can help me here.

I have changed the entire case from the htc one.

Since then the bottom speakers dont work.

I've checked all contacts and Pins.

A second microphone board and speaker but nothing work,

The bottom speaker dont work..

For testing,

I cut the wires from the speaker and connected it to the upper speaker.

Then it works perfectly ..

Is there a separate chip could be defective for the bottom speakers?

Or can someone give me the points on the main board to call him to solder directly?

Only one speaker is not really true.

Thanks!

Excuse me for my bad english