The video posted by Sir above is one of the best examples, starring one of the best callmakers.
Not all boxes are created the same; some will produce a gobble better than others.
You can tweak the sounds by the way you hold the box while moving the lid across the two rails, and where you place your index finger and thumb along the length of the lid. Each change you make in holding the box call will change the tone.
You can dip the call forward a bit to take some of the weight of the lid off and that may help produce a better gobble or hold it flat to max out the weight of the lid. Another technique for short boxes is find a rubber band that holds the lid against the box snugly but not tight. I have an all walnut short box that gobbles great with a rubber band around it and I shake it holding the base and the handle facing away from me.
Like every turkey call, more you practice the better you get producing the sounds which please your ear.