I recently purchased a Energy ESW-8 sub and a Polk Audio PSW110 sub. Even though I love my Energy C-100 speakers I prefer the Polk sub over the Energy sub so I decided to keep the Polk and send back the Energy and it sounds great but I still DO NOT know what these features are for ( the manual does not provide such info).I was also a little curious as to where most people set there volume on ther sub.