Xperia Z5 dual Bottom speaker not working

[KaiL91]

Sony Xperia Z5 bottom speaker not working. 

I tried in safe mode. I tried factory reset. Still no hope! What could be the issue?

[Qatrium]

@KaiL91

Go to Settings -> About phone -> Diagnostics -> Test -> Loudspeaker. Can you hear the sound coming from both speakers?

[KaiL91]

I tried in diagnostic. But only the top speaker rings. Bottom speaker is silent. 

[Qatrium]

@KaiL91

Did you expose your phone to water lately?

[KaiL91]

No. I always keep it dry even sony says it's water resistant / proof. 

[Qatrium]

@KaiL91

I'm afraid that this may indicate a hardware problem. But as a last resort, try performing a software repair using Xperia Companion. This will do a clean installation of the latest firmware and will also wipe your internal memory. Don't forget to backup using Xperia Companion, but preferably without adding apps or settings to the backup.

Follow the steps given in blue links, and keep us updated. If the speaker fails to operate after the software repair process then you should contact your Local support and get your phone inspected by a professional.

[KaiL91]

God! This is my second handset which was replaced to me by sony. The previous handset too had some gyro sensor malfunction. And now this. It's still under warranty so will this issue be covered under warranty?  And if confirmed a hardware issue, will it be replaced by sony under warranty?