The following table is based on measurements, not manufacturer specs. Target SPL is 110 dB SPL. The source is assumed to output 2 V. The amp is assumed to be a voltage source (0 ohm output impedance). Voltage, current, power are RMS figures. What do the columns mean? S@1V is the sensitivity with 1 V, 500 Hz sine wave input in dB SPL. Z is the impedance at 500 Hz in Ω. Voltage is the required voltage to reach the target SPL. Current is the required current to reach the target SPL in milliamperes. Power is the required power to reach the target SPL in milliwatts. Gain is the gain the headphone amplifier theoretically needs to reach the target SPL without excess gain. If needed you can add a few dB excess gain (suggestion: 3 to 9 dB). Notes: 1 kHz: the measurement was done at 1 kHz instead of 500 Hz specs: based on specifications provided by the manufacturer, not independent measurements nc: noise canceling enabled There is no guarantee that the data is 100% correct. The sensitivity of some headphones can vary as much as +/- 3 dB (some manufacturers even specify this explicitly). ManufacturerModelS@1V [dB SPL]Z [Ω]Voltage [V]Current [mA]Power [mW]Gain [dB]Notes AKGK240 Studio103642.23934.9878.3111 AKGK271 MK II106651.58524.38338.644-2 AKGK272 HD11065115.38515.385-6 AKGK550115350.56216.0679.035-11 AKGK601991313.54827.08596.1015 AKGK701105651.77827.35848.65-1 AudezeLCD-2108451.25927.97635.22-4 AudezeLCD-3102482.51252.331131.4492 Audio TechnicaATH-AD700113350.70820.22714.32-9 Audio TechnicaATH-AD900114370.63117.05310.76-10 Audio TechnicaATH-AD900X114380.63116.60410.477-101kHz, specs Audio TechnicaATH-ANC7B1183050.3981.3050.52-14nc Audio TechnicaATH-ANC91091001.12211.2212.589-5nc Audio TechnicaATH-M50115380.56214.7988.322-11 Beats by Dr. Dre Pro117180.44724.81611.085-13 Beats by Dr. Dre Studio1212160.2821.3050.368-17nc BeyerdynamicCustom One Pro116180.50127.84413.955-12 BeyerdynamicDT770 Pro982513.98115.86163.14361kHz BeyerdynamicDT770-32111320.89127.85224.823-7 BeyerdynamicDT770-6001005573.1625.67717.9534 BeyerdynamicT1997503.5484.73116.7865 BeyerdynamicT5p116410.50112.2246.127-12 BeyerdynamicT7011038012.6322.632-6 BeyerdynamicT901023082.5128.15520.4862 BoseAE2112360.79422.06517.527-8 BoseQC1511348000.7080.1470.104-9nc Bowers & WilkinsP5117270.44716.5447.39-13 DenonAD-D2000115250.56222.49412.649-11 DenonAH-D1001112310.79425.62320.353-8 DenonAH-D7000114250.63125.23815.924-10 DenonAH-D7100108301.25941.96452.83-4 Fischer AudioFA-003117750.4475.9562.66-13 FostexT50RP107541.41326.15836.949-3 FostexT7113800.7088.8496.265-9 FostexTH900108251.25950.35763.396-4 Grado LabsSR60i to 325i111340.89126.21323.363-7 HifimanHE-4906310158.731587.30214 HifimanHE-500102342.51273.879185.5762 HifimanHE-6894311.22260.9352927.73415 HifimanRe0118600.3986.6352.641-14 KRK SystemsKNS640011034129.41229.412-6 KRK SystemsKNS8400106351.58545.28371.768-2 SennheiserAmperior113220.70832.17922.781-9 SennheiserCX880120340.3169.3012.941-16 SennheiserHD202119340.35510.4363.703-15 SennheiserHD280 Pro114730.6318.6435.454-10 SennheiserHD555/595114720.6318.7635.529-10 SennheiserHD558/598112700.79411.3489.014-8 SennheiserHD6001053221.7785.5239.821-1 SennheiserHD6501043331.9955.99211.9550 SennheiserHD7001051991.7788.93615.891-1 SennheiserHD8001034302.2395.20611.6561 SennheiserIE800125180.1789.8791.757-21 SennheiserPX100 II114340.63118.55811.709-10 SennheiserPX200 II115380.56214.7988.322-111kHz ShureSE215126180.1588.8051.395-22 ShureSE535133360.0711.9670.139-29 ShureSRH1440107381.41337.17252.507-3 ShureSRH1840102662.51238.05995.62 ShureSRH440116410.50112.2246.127-12 ShureSRH750113390.70818.15212.851-9 ShureSRH840116440.50111.3915.709-12 ShureSRH940113400.70817.69912.53-9 SkullcandyAviator118360.39811.0594.402-14 SkullcandyCrusher114320.63119.71712.441-101kHz, specs SkullcandyMix Master119200.35517.7416.295-15 Sol RepublicTracks118600.3986.6352.641-141kHz SomicMH463106451.58535.2255.82-21kHz, specs SonyMDR-MA900111150.89159.41752.955-7 SonyMDR-XB1000115270.56220.82711.712-11 SonyMDR-XB500123430.2245.2061.166-19 SonyMDR-XB700115280.56220.08411.294-11 SuperluxHD668b108611.25920.63825.982-4 SuperluxHD66911062116.12916.129-6 TakstarHI2050104601.99533.25466.35101kHz, specs UltrasoneEdition 8115340.56216.5399.301-11 UltrasoneHFI580115360.56215.6218.784-11 UltrasoneHFI680115750.5627.4984.216-11 UltrasoneHFI780116400.50112.536.28-12 UltrasonePro550117650.4476.8723.07-13 UltrasonePRO750114410.63115.3899.71-10 UltrasonePRO900108431.25929.27736.858-4 V-ModaCrossfade M100115360.56215.6218.784-11 YamahaPRO 300116580.5018.6414.331-12 Some have raised concerns with 110 dB SPL being too loud. Well, that is just the absolute highest SPL you can reach with a full-scale 500 Hz tone and the volume set to max. Music has a higher crest factor than sine tones, which means that the RMS value will be much lower. The following graphic shows a volume control with a 15A taper pot as found in many heapdhone amps. Ideal range should be somewhere between 10 and 2 o'clock. The inner labels show the attenuation of the pot at each full hour. So 110 becomes 95 dB SPL at 12 o'clock. The outer blue/red labels show the overall perceived SPL of an uncompressed classical track and a heavily compressed metal track respectively. Loudness was calculated using an EBU R128 compliant scanner. Obviously, you can really hurt your hearing if you listen to highly compressed music and turn up the volume. With less compressed music overall levels will be a lower but there can still be very loud passages or short peaks in SPL. So turn the volume down - better be safe than sorry. Don't rely on calculations only. Use a sound level meter. Please let me know if you find that some values are completely off or want some headphones added.