Вот наткнулся на ранее выпускаемые модели наушников и их классификация в омах, сама тема относится к усилителю для наушников, но больше полезной инфы по моделям http://www.bottlehead.com/et/whichheadphoneamp.htm
AKG- K141M (600 ohms), K240, K240M, K240DF (600 ohms), K241 (600 ohms), K250 (600 ohms), K260, K260 pro (600 ohms), K340 (360 ohms)
Beyer Dynamic- DT 100 (400 ohms), DT 150 (250 ohms), DT 250-250 (250 ohms), DT 411 (250 ohms), DT 511 (250 ohms), DT 531 (250 ohms), DT 550 (600 ohms), DT 660 MKII (600 ohms), DT 770 (250 ohms), DT 770 (600 ohms), DT 770 pro (250 ohms), DT 801 (250 ohms), DT 811 (250 ohms), DT 831 (250 ohms), DT 880 (250 ohms), DT 880M (600 ohms), DT 880 Pro (250 ohms), DT 880 S (600 ohms), DT 901 (250 ohms), DT 911 (250 ohms), DT 931 (250 ohms), DT 990 (250 ohms), DT 990 Pro (250 ohms) Tesla T1 (600 ohms)
Sennheiser- HD 222 (600 ohms), HD 230 (600 ohms), HD 250 II (300 ohms), HD 420 (600 ohms), HD 420SL (600 ohms), HD 425 (600 ohms), HD 430 (600 ohms), HD 540 (600 ohms), HD 560 II (300 ohms), HD 580 (300 ohms), HD 600 (300 ohms), HD 650 (300 ohms), HD 800 (300 ohms) , HDC 451 (250 ohms), PXC 150 (300 ohms), PXC 250 (300 ohms), PXC 300 (300 ohms)