Dynamic noise filter plugin for XMMS. This plugin filters out tape hiss from old recordings, with minimal damage to the music. It has an adjustable squelch threshold, so you can control how much is filtered out.
Version 0.2 adds "softsquelch", an option which smooths the boundary between squelch and non-squelch mode, for a less noticable transition.
Version 0.3 adds a user selectable number of bands, from 3 to 12, and a test button that cuts out filtering in the right channel for A/B comparision.