Surge XT routes modulation by selecting a source, engaging routing mode, then dragging a blue depth slider

Modulation assignment in Surge XT follows a three-step click-click-drag workflow that is different from most synthesizers. First, click a modulation source (LFO, envelope, etc.) in the routing bar to select it. Second, click it again to engage routing mode — it turns bright green and blue modulation sliders appear over every modulatable parameter. Third, drag the blue slider to the value the parameter should reach at the modulation peak. The range bar shows the full modulation sweep. Click the source once more to disengage. Modulation depth is always relative to the parameter’s base value: moving the base slider shifts the entire modulation range up or down. If the blue slider sits below the base value, modulation polarity is inverted. You can also drag a source directly onto a parameter to open a numeric amount dialog.

Examples

To modulate filter cutoff with LFO 1: click LFO 1, click it again (green), drag the blue cutoff slider to desired peak, click LFO 1 again to exit routing mode.

Assessment

Describe the three steps to assign LFO 1 to filter cutoff in Surge XT. Then explain what happens to the modulation range if you move the gray (base) cutoff slider upward after the modulation is assigned.