On the SD40, there is no dedicated vocalizer button on the panel as is the case with the SD7 (due to a smaller panel ofcourse) so ... the status of the vocalizer is on the screen (when you press and hold down the MIC button for 2 seconds to display the SD9 sceen above shown by Paul).

Now, the left side of the screen is for MIC status (on/off) and controls, while the right side of the screen is for vocalizer. From this screen, if you turn on/off vocalizer, you will see the on/off icon to the right go yellow (on) or blue (off) - you can do so eithe directly on this screen by touching on/off or using pedals - status will still be displayd. For SD9/SD90/SD60, the panel is big enough to inlcude a dedicated vocalizer button and volume slidder.

We are working on another external/panel suggestion (e.g Mic button should FLASH when vocalizer is on) - this way, the user immediately knows the status of the harmonizer -:)

Thanks,