Also an audio player by Unsanity for MacOS.
While the visuals and audio quality are fairly standard, the real claim to fame Echo has is its skin support, including some of the first actual innovations seen since Audion's limited animations and alpha-blending (though Echo doesn't actually have alpha-blending at this point).
Among these are attaching scripts to the skins which allow for multiple windows, inlined video, curved sliders, and other niceties.