Measurements
Click on graphs image to download .pdf for closer inspection.
Charts for the PM-1 with both velour and leather pads are shown above. Aside from the slightly less reliable seal of the leather pads (as seen in the variations in the raw FR plot) and the very slightly brighter sound of the leather pads (as seen in the slightly raised leading edge of the 300Hz square wave) the two sets of measurements are quite similar and I'll adress the measurements as a whole.
Again, raw FR plots show…