analog modular synth interface

has anyone sent analog modular synthesizer control voltages into an arduino?

i need a circuit for sending one into the ADC input of the duo. my synthesizer typically can produce 0-5v or 0-10v control voltages. looks like i need to scale it down to 0-3.3v for the duo?

has anyone done this yet? are there any other concerns i need to be aware of? a schematic for this input scheme would really help. more info is better than less as i am a noob at this.

thanks so much!