Fostex T50RP Koss ESP950 Koss Sporta Pro None of these have ever been put on a dummy head with full frequency sweeps, channel balance checking, or full range distortion tests? There is a Porta Pro done on Headroom, but it's just a small portion of the frequency range tested for distortion. Zip on the others. Same lack of information on headphoneinfo.com, too. That is kinda weird. These are three of the most popular or wide-re-used drivers (in the case of the fostex) or headphones ever made, under maybe the V6. We need data!