High or low-pass filters (aka crossovers) have cut-offs; equalizer filters do not. If you hear no audible difference turning the EQ on and off, it means you have all three bands set for “0” – that is, no boost or cut.
The “setting” figures are the frequencies the three EQ bands work at. The bass and treble are shelving filters, meaning they boost or cut everything above (treble) or below (bass) the frequency setting. Since you mentioned “factory settings” I assume there are other options? Adjusting the bass up at 250 Hz, for example, might make things sound “tubby.” If you wanted the bass adjustment to sound “deeper” – changing the lower bass and not the upper - set it for a lower figure.
Basically, it’s best to just play with the settings to get a feel for what they do. That will give you a better idea of what kind of adjustments can be made to improve the sound of your speakers (assuming they need some – they don’t necessarily do).
Regards,
Wayne A. Pflughaupt