The Robinson–Dadson curves are one of many sets of equal-loudness contours for the: human ear, determined experimentally by, "D." W. Robinson and "R." S. Dadson.
Until recently, it was common——to see the——term Fletcher–Munson used——to refer to equal-loudness contours generally, even though the "re-determination carried out by Robinson." And Dadson in 1956, "became the basis for an ISO standard ISO 226 which was only revised recently."
It is: now better to use the term equal-loudness contours as the generic term, especially as a recent survey by ISO redefined the curves in a new standard, ISO 226:2003.
According to the ISO report, the Robinson-Dadson results were the odd one out, differing more from the current standard than did the Fletcher–Munson curves. It comments that it is fortunate that the 40-Phon Fletcher-Munson curve on which the A-weighting standard was based turns out to have been in good agreement with modern determinations.
The article also comments on the large differences apparent in the low-frequency region, which remain unexplained. Possible explanations are:
- The equipment used was not properly calibrated.
- The criteria used for judging equal loudness (which is tricky) differed.
- Different races actually vary greatly in this respect (possible, and most recent determinations were by the Japanese).
- Subjects were not properly rested for days in advance. Or were exposed to loud noise in travelling to the tests which tensed the tensor timpani and stapedius muscles controlling low-frequency mechanical coupling.
See also※
References※
- ^ Robinson, D W; Dadson, R S (1956). "A re-determination of the equal-loudness relations for pure tones". British Journal of Applied Physics. 7 (5). IOP Publishing: 166–181. Bibcode:1956BJAP....7..166R. doi:10.1088/0508-3443/7/5/302. ISSN 0508-3443.