Some of the headphones whose measurements are included here passed through my hands before my expanded range of tests had been developed. Rather than exclude them because of that, I've posted what results I can. Models in this category are identified in the listings by an asterisk after the product name, for example the (Sennheiser) HD 800 S *. Where I still have samples of older headphones, I have instead retested them using the full suite of HTL measurements.
One difference to note between the legacy and later measurements is that the former were conducted with previous-generation KEMAR artificial pinnae and the GRAS RA0045-S1 ear simulator. The results obtained with these are not quite the same as with their replacements, the largest frequency response disparities occurring in the lower treble (unexpected) and above 10kHz (expected).