I'm a newbie trying to get familiar with Premiere 6.5 while compiling hundreds of video clips taken from a Canon digital camera. Everything I import into Premiere has a very distinct echo in the first few seconds of the clip. The echo is very noticeable in preview and in the exported product. I've tried multiple settings and formats.

When viewing the audio waveform, it wil not depict the echo I am hearing.

How do I remove this unintended effect?