I belive what UD means is this:
* Connect your Mic directly to the Mixing board (say on Channel 1).
* Each of the channes of your board should have AUX1, AUX2, AUX3 or a send for each channe. Turn up/activate AUX1 and connect the AUX1 output from the mixer back into the SD1 (you might have to go through a Direct Box so as to get the XLR output into the SD1 or just use a cable that is 1/4" on one end and XLR on the other - since the SD1's vocalizer can only be activated from a signal coming into the XLR MIC1 input).
* Now connect the MIC1 OUTPUT of the SD1 to the Mixing board (say on Channel 2). BUT, go into the VOCALIZER EDIT and turn down the LEAD CHANNEL (which you already capture on Channel 1 of the mixer) and turn up the VOCALIZER (which you now capture on channel 2).
* This way, when you turn up CHANNEL1 on the mixer, you get your clean voice (without effects or harmony from the Vocalizer) and when you turn up CHANNEL2, you get the VOCALIZER with effects etc... from the SD1).
Hope this better explains ... add on UD if I missed something.
Thanks,
AJ