Note that you can filter other payloads as well, not just songs. So for artists you could modify the filter to include only artists where you have listened to at least one of their songs
Field=Artist&Files=[Media Type]=[Audio] [Number Plays]=>0
or artists that have at least one song rated higher than 3 stars
Field=Artist&Files=[Media Type]=[Audio] [Number Plays]=>0
This is a really effective way to reduce the strain on your resources (memory), reduce the load times for VC and at the same time, improve the accuracy of your recognition. If however you only have an average sized library (i.e around 10K songs or less) and it is cleanly tagged, then you may not need to use filtering at all, and can include all your songs, all your artists, all your albums etc. Even in this case you may find a use for the filtering somewhere down the road when playing with TV shows, or photos...
One thing I should point out to help avoid confusion, JRiver filters are a bit quirky when it comes to using values and the less than or greater than comparison operators.
[Number Plays] => 0 kind of looks like it means Number of Plays is greater than or equal to 0, but it doesn't, it actually mean is equal to greater than 0
if you want to filter using greater than or equal to, then you would write: =>=