Set the level of the LFE to Rev slider: Move to adjust the output level of the LFE channel independently of other surround channels.
Set the level of the C(enter) slider: Move to adjust the output level of the center channel independently of other surround channels.
Set the level of the Bal(ance) slider: Move to set the level balance between the front (L-C-R) and rear (Ls-Rs) channels.
In 7.1 ITU surround, the balance pivots around the Lm-Rm speakers, taking the surround angles into account.
In 7.1 SDDS surround, the Lc-Rc speakers are considered front speakers.
Set the level of the Dry slider: Move to set the overall level of the non-effect signal for all channels. Move the slider to a value of 0 (mute) when using Space Designer as a bus effect in an aux channel strip. Use the Send knob of each bussed channel strip to control the wet/dry balance.
Set the level of the Wet slider: Move to adjust the output level of the effect, or wet, signal for all channels.
The X-Over (crossover) slider setting and Hi and Lo Spread knob values enhance the perceived width of the signal. This occurs without losing the directional information of the input signal normally found in the higher frequency range. Low frequencies are spread to the sides, reducing the amount of low frequency content in the center—allowing the reverb to encompass the mix.
Logic Pro Instruments: PDF