My imported audio files distort-any ideas whats wrong?

Hi, I am using Sonar Home Studio 7XL and a Boss BR-800 I have recorded some guitar and vocals on a Boss BR-800. The levels are fine and don't distort on playback. I have converted the Boss files to wav using the included software, BR series wave converter, so I can import the recorded tracks into HS7. There are no adjustments available in this process, it is automatic. When I import the audio file into an audio track the result is a distorted, clipped track. you can see the top and bottom of the signal don't fit into the track view and it sounds distorted on playback I have adjusted the output of the BR-800 (variable from -20db to +20db)but there is no difference so I guess the output via USB is actually fixed. Is there a way of reducing the input on HS7 somehow? bearing in mind I am not recording and have no volume to control, just importing a file. I don't have any effects set in HS7 it should be a clean import. Thanks

Thanks for your reply. The conversion takes place on my PC. the BR-800 connects by USB then the wave converter program is opened on the computer and the song is selected. The song files (ie tracks and virtual tracks) are converted to wav and saved in a folder as separate files. Each file can then be opened as a separate audio track in HS7. Unless HS7 is doing something to the file when it opens ie adding gain/boost/distortion effect without me knowing then I agree it must be in the conversion. I have tried adjusting the BR=800 settings ie output level, mastering and it makes no difference at all. I can't see any effects on in HS7 Thanks Pete

OK thanks, there's no distortion in media player.

What confuses me here is:
The OP says the waveform is visually clipped. That must be a misinterpretation (?) as if that is the case, it should distort in WMP too, shouldn't it?

This doesn't sound like a sample rate thing, either.
Maybe WMP and SONAR are using different soundcards or something???