1993 eclipse engine noise-tensioner?

1993 eclipse with 155k miles. There is a loud noise sounding as if the timning belt were rubbing. When revved to 2500rpm, the engine quiets down to normal. I removed the top timing belt cover and the noise remains(below 2500rpm). Also, the belt is not frayed. Any suggestions?

You more than likely have a problem with your tensioner or idler pulley.