Hisenior Okavango: how much amplifier do you need?

The Hisenior Okavango is 20Ω with a sensitivity of 112.0 dB/mW, which is 129.0 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 0.06 mW, or 36 mV across the drivers.

That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 280 have at least 10 dB of headroom and another 0 have enough. The cheapest portable source that does the job is the Apple USB-C dongle (US) at $9.

The two numbers that decide everything

Impedance20 Ω
Sensitivity112.0 dB/mW
Sensitivity (voltage)129.0 dB/V
Power for 100 dB SPL0.06 mW
Voltage for 100 dB SPL36 mV
TypeOver-ear
Easy to drive — anything will do it
All 280 sources at 100 dB SPL into 20Ω
Comfortable 280Enough 0Marginal 0Not enough 0
Cheapest portable source that does it
$9 · USB dongle · +25 dB headroom
Cheapest desktop amp with 10 dB to spare
$75 · desktop DAC/amp · +32 dB headroom

Sensitivity here is in dB per milliwatt. Why the unit matters.

Where this sensitivity figure comes from

Hisenior publishes this directly as 112 db@1mW (@ 1 mW (printed verbatim as '112db@1mW')), per milliwatt, so nothing was converted.

Hisenior prints the impedance as 20Ω±10%, not as a bare number. Everything on this page is calculated with the nominal 20Ω, and the rest of that line is quoted here rather than tidied away, because how a figure is qualified is part of the specification too.

Source: hisenior-iem.com. How this data was built.

What is printed there, and what it is worth

As it is labelledAs printedToleranceStandard
Tech Specifications10Hzz-30Khznot printednot printed

Hisenior prints 10Hzz-30Khz for the Hisenior Okavango, under the heading “Tech Specifications”. Source: hisenior-iem.com.

Printed as "10Hzz" with a doubled letter. Quoted here exactly as it stands on the page.

No tolerance is printed with it, so “10Hzz-30Khz” says nothing about how loud this headphone actually is at 10 Hz.

Only what the maker printed; maker by maker.

Power, voltage and current by listening level

LevelWhat it isPowerVoltageCurrent
85 dB SPLquiet background listening0.00 mW6 mV0.3 mA
95 dB SPLnormal listening0.02 mW20 mV1.0 mA
100 dB SPLloud listening0.06 mW36 mV1.8 mA
105 dB SPLvery loud0.20 mW63 mV3.2 mA
110 dB SPLpeaks on dynamic music0.63 mW0.11 V5.6 mA

Most people listen between 75 and 85 dB; the 100 dB row leaves room for peaks.

The cheapest sources that drive them with room to spare

The 15 cheapest of the 280 sources here that reach 100 dB SPL into 20Ω with at least 10 dB of headroom and no known hiss or output-impedance problem with these headphones. All 280 sources, judged for these headphones.

SourceTypePricePower into 20ΩHeadroomVerdict
FiiO SnowSky Tiny AUSB dongle$2240 mW+28 dBComfortable
FiiO SnowSky Tiny BUSB dongle$2254 mW+29 dBComfortable
Tanchjim Stargate IIUSB dongle$4078 mW+31 dBComfortable
ddHiFi TC35ALUSB dongle$46131 mW+33 dBComfortable
ddHiFi TC35AirUSB dongle$46131 mW+33 dBComfortable
Fosi Audio N3Bluetooth receiver$5086 mW+31 dBComfortable
Hidizs SD2USB dongle$5044 mW+28 dBComfortable
iFi GO linkUSB dongle$5944 mW+28 dBComfortable
Kiwi Ears Allegro ProUSB dongle$6042 mW+28 dBComfortable
ddHiFi TC35Pro (Mountain2)USB dongle$6641 mW+28 dBComfortable
DUNU DTC 480USB dongle$7041 mW+28 dBComfortable
EPZ TP35 ProUSB dongle$7070 mW+30 dBComfortable
Aiyima A2 Prodesktop DAC/amp$7594 mW+32 dBComfortable
ddHiFi TC35Pro (Eye2)USB dongle$7641 mW+28 dBComfortable
ddHiFi TC44 Pro E2USB dongle$99156 mW+34 dBComfortable

The three ways a source goes wrong

Hiss. At 129.0 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 37 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.

Output impedance. At 20Ω these want a source output impedance below 2.50Ω to satisfy the one-eighth rule; 35 of the 192 sources that publish one miss it. Check yours here.

Similar headphones

Compared with its stablemates: vs Mega5EST.

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