Answer: The inner breath knob is meant to adjust the breath to filter ratio. In other words, by turning the knob clockwise it will make the filter open wider to breath pressure. See the question regarding setting the breath knobs. If the knob has no effect, the filter is probably wide open, even when you are barely blowing into the instrument. Nyle Steiner indicates that the most likely cause of this in the case of an EWI1000 is the breath transducer in the EWI controller itself. The breath transducers have a way of shorting out due to moisture build-up in the area. The transducer will have to be replaced. They are available from International Music Corp. (IMC). Akai's transducers are, unfortunately, inconsistent in their performance so don't be surprised that after installation of the new transducer the EWI "feels" slightly different. The usual difference is in the "breath curve", the amount of breath necessary to reach maximum volume. Nyle Steiner also makes a breath transducer replacement which I have in all of my EWI's and they work better than Akai's.  In the 3000 and 3020 the transducers have been replaced with a solid-state part.