What version of Premiere Elements and on what computer operating system is it running?
What are the properties of your source media? If you do not know, telling us the brand/model/settings of the camera that recorded the video should give us that type of information.
Are you saying that original video (before Premiere Elements import) plays with even volume; whereas the imported audio plays with high and low spots? If not, please explain further the Premiere Elements audio volume situation.
Premiere Elements comes with volume controls. Can you edit the volume to the wanted level using the volume control and an opened Audio Meter to act as guide? (See Window Menu/Audio Meters).
Let us start here and then decide what next.
I think that the problem was that the original video has 5.1 sound and project does not have. I did not change project setting in the beginning.
Thanks for analyzing the issue and coming up with an possible explanation for your audio question.
But, let us see if we can rule in or out the factor that you suggest.
Still need to know what version Premiere Elements and on what computer operating system is it running.
Now the additional questions that become important
a. what are the properties of your 5.1 Channel/video source file that you have brought to the Timeline?
b. there are a limited number of project presets which are described for 5.1 channel and we need to see if the one that you need for video properties also includes 5.1 channel description....if not, I can tell you how to create that special video/5.1 channel project preset.
But, at this point, I am not convinced that the 5.1 channel audio in the file is at the core of your issue. But, let us see. We will not know unless we test that thought.
Thanks for the update.
Your results point to your video audio (5.1 channel) needing a project preset which included the 5.1 audio description.
Now that you are using the preset with 5.1 channel, you will find that you can now take your Timeline content to an export with 5.1 channel audio as described in my studies in the following link.
I have other studies on Premiere Elements and import/export related to 5.1 channel. If needed, please let me know, and I will post the links to them.