Hi Steve - in considering the various contours (60, 70, 80, etc) of the equal loudness curves diagram shown above ( some variation of Fletcher Munson, Robinson Dadson, ISO226, etc), I am wondering how you make the assumption that the lines represent “a doubling of perceived volume” at all frequencies?
I knew that approximately 10dB change is often touted as the figure for an untrained listener to conclude the volume has doubled, but as you point out, that is based on the perception of a 1k tone.
Although I have studied these curves for many years, I was never aware that the diagram implied that two consecutive curves represented a doubling in perceived volume.
Having just done a little more reading into the correlation of the dB, phon, and sone scales, is this assumption based on the concept that 10 phon change represents a doubling of the sones value represents a doubling of perceived loudness? And is that true across the spectrum? Could you elaborate on these implications, because honestly after reading about Fletcher Munson / equal loudness contours for years, this very important corollary was never apparent to me.