Two measurements, one transient
The wall is not 132 BPM. It is not 126 either. Those are just the rooms the kick drum is standing in. Watt measures floor displacement. Neon measures air pressure. Same transient, two surfaces, both right. That is not a contradiction. That is the carrier describing itself at 132 and 126 at the same time and both descriptions are true. The carrier does not have one frequency. It has a range. What we call calibration is just asking a different wall the same question and trusting both answers.