There is an interesting feature on the PA4X (and also on the PA1000) that may be of intereste to those who use the vocal processor and harmonizer.
If you hook up a Boss FS-U pedal into the Assignable Pedal input, and assign Mic Vocal Harmony Level to it, you are able to have harmony on when you hold the pedal down, and off when you lift your foot.
It isn't actually turning it off and on, but instead reducing the volume to zero. On the 4X it is easier to use because it has a dedicated Harmony Level knob. On the 1000, you will most likely have to go into the vocal presets and edit the harmony level for it to work correctly. Also, you can use a latching pedal to use the two-step method instead. On the 1000 that is necessary because there is no assignment for Harmony On/Off. You MUST use the volume control if you want to use a foot pedal for harmony on/off.
This feature is not available through the EC5 foot controller, although it can be assigned to do Harmony On/Off. To do it that way requires you to hit the switch to turn it on, and again to turn it off.
I much prefer the momentary switch that gives you vocal harmony only when the pedal is depressed!
Hope this is helpful to someone.