@Dipil 

Hi,
It's not recommended to mount the camera upside down since it may affect the camera's detection feature. 

If you need to see an upside-down image, you can go to the Tapo app> Camera's Device Settings>Video & Display page to enable the Invert Image feature, and then the Live View image will be inverted. The speaker is a built-in hardware of the camera and won't change because of the image inverts.

You may send us more detailed information, such as your usage scenario, a picture of the location and angle you want to mount the camera, and a picture of the area you want to monitor, so we can check if your installation is suitable.

Best Regards

  @Dipil 

Hi,
When the camera's speaker is upwards, there will be standing water on the speaker part when rains, generally, the water won't come into the camera since it's waterproof, but the camera's audio performance will be greatly affected because of the standing water. 
If the speaker part always has standing water, it may affect the camera's lifetime, and we do not recommend mounting the camera upside down.
Best Regards