WOW is just one of the different wave patterns that the ValueJet series of printers can use. There are about 7 different wave patterns WAVE, WOW, FUZZ, FINE&FUZZ, FINE&WAVE, SUPERFINE WAVE A, and, SUPERFINE WAVE B. To change it on the keypad of the printer you go into the Menu > Setup > Set 3 Effect. You will have to make sure that your rip software isn’t overriding the setting. I don't have a 1604 in my office anymore to check it with but you can try to upgrade the firmware to the latest version and see if it was added to the menu. I believe that the latest version is 1.19 for the 1604. Make sure that you also update the Heater Controller Board firmware as well otherwise the new main board firmware might not be able to talk correctly to the heater controller board.