Why two spec sheets can list the same driver and still not be comparable
Manufacturers do not share one measurement convention. Moondrop and Truthear print sensitivity per volt (dB/Vrms); Meze and Kiwi Ears print it per milliwatt (dB/mW); KZ frequently prints a bare dB with no basis at all. Between those conventions the same earphone can differ by 15 to 20dB on paper, which is larger than most of the differences buyers are trying to judge. This index records the original wording for each entry rather than normalising it, and flags entries where the basis is unstated, the sheet is self-contradictory, or a nozzle variant changes the figures.