1)  If the predefined volume of articulations relative to one another do not suit you, you can adjust the  volume of individual articulations by going to the instrument pane in the bottom right hand corner, selecting the articulation you wish to adjust, pressing the ‘edit articulation only’ button, and adjusting the volume fader in the instrument pane. 

While you have ‘edit articulation only’ selected you can further play with the velocity controls in the ‘voices and layers’ pane (adjacent to the instrument pane) to help you get the response you desire.

2)  If  you go to the free user download area /extra downloads/superior/edrums and download the edrum guide pdf, there are guidelines on how to adjust the foot splash response.  These guidelines are for Superior 1 but they are easily translated to Superior 2.

The alternative is to turn the foot splash off completely by selecting the ‘open pedal’ articulation only, going to the voices and layers pane and under layer limits select zero for each of the soft, gradient and hard hits.

Out of interest which hihat are you using.  Is it a Hart or Roland?