When the Synth effect is applied, it generates a synthetic tone that is based on the pitch and frequency of inital input. The effect can be sequenced and adjusted using several parameters, including the frequency, Resonance, decay and ballance.
Your voice controls the pitch of the synth effect.
The Resonance parameter controls the emphasis of the Frequency at the cutoff point you set. Turning the knob clockwise emphasizes the frequency at the cutoff point, while turning it counterclockwise reduces the emphasis.
The Decay parameter controls the decay time of the synth effect. Basicly "how fast the pitch falls".
The Balance parameter controls the balance between the dry and wet signal. Turning the knob clockwise increases the wet signal, which is the sound of the synth effect, while turning it counterclockwise increases the dry signal, which is the original sound without the synth effect.
Overall, the Synth effect on the RC-505 Loop Station can add a unique and interesting layer and initial hits.
Image By glacial23 - Early MinimoogUploaded by clusternote, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=9995768