In fact, the Doppoler is NOT a ?rotary simulator? but the brain of a system that in his best setting is made of two cabinets, positioned at 180? from each other, to let the Doppoler handle it reproducing what happened to signal when the speaker is rotating. We paid a lot of attention, measurement, tests, to exactly understand and reproduce what happens to the signal coming to our ears with a rotary speaker. This meant to apply eq filters, phase changing, volume changing, and calculate how reflections reacts and a?ect all of this..Indeed, the signal coming out from Front and Rear speaker are quite di?erent from each other, cause they are already made to do their job in the correct position. Speed sets the speed of rotary e?ect, and can also be set by the TAP tempo footswitch. Level sets the level of rotary e?ect and the ambient. The result, is an outstanding tridimensional sounds that will force you to keep it always ON, even with low speed and intensity without notice the rotary e?ect, just adding ambient and 3D to your sound. So we started designing it from the acoustic point, wanting to keep it intact and the base of our system, then we designed our circuit to reproduce what happens between the cabinet and our ears. So far from a simple tremolo/rotating simulator. You can easily use it in your pedalboard in front of your amp, and easily add just an additional speaker behind your main speaker.. maybe an active cabinet, a combo amp, or using one of our Miniamp to drive a guitar Speaker.