Dunu Glacier: how much amplifier do you need?

The Dunu Glacier is 43Ω with a sensitivity of 109.0 dB/mW, which is 122.7 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 0.13 mW, or 74 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

Impedance43 Ω
Sensitivity109.0 dB/mW
Sensitivity (voltage)122.7 dB/V
Power for 100 dB SPL0.13 mW
Voltage for 100 dB SPL74 mV
TypeIn-ear monitor
Easy to drive — anything will do it
All 280 sources at 100 dB SPL into 43Ω
Comfortable 280Enough 0Marginal 0Not enough 0
Cheapest portable source that does it
$9 · USB dongle · +23 dB headroom
Cheapest desktop amp with 10 dB to spare
$75 · desktop DAC/amp · +29 dB headroom

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

Where this sensitivity figure comes from

Dunu publishes this directly as 109 dB/mW ((@1kHz) (DUNU also prints 122 dB/Vrms at 1 kHz)), per milliwatt, so nothing was converted.

Dunu prints the impedance as 43 Ω at 1 kHz, not as a bare number. Everything on this page is calculated with the nominal 43Ω, 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: dunu-topsound.com. How this data was built.

What is printed there, and what it is worth

As it is labelledAs printedToleranceStandard
FREQUENCY RESPONSE5 Hz - 40 kHznot printednot printed

Dunu prints 5 Hz - 40 kHz for the Dunu Glacier, under the heading “FREQUENCY RESPONSE”. Source: dunu-topsound.com.

No tolerance is printed with it, so “5 Hz - 40 kHz” says nothing about how loud this headphone actually is at 5 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 mW13 mV0.3 mA
95 dB SPLnormal listening0.04 mW41 mV1.0 mA
100 dB SPLloud listening0.13 mW74 mV1.7 mA
105 dB SPLvery loud0.40 mW0.13 V3.0 mA
110 dB SPLpeaks on dynamic music1.3 mW0.23 V5.4 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 43Ω 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 43ΩHeadroomVerdict
FiiO SnowSky Tiny AUSB dongle$2225 mW+23 dBComfortable
FiiO SnowSky Tiny BUSB dongle$2225 mW+23 dBComfortable
Tanchjim Stargate IIUSB dongle$4056 mW+26 dBComfortable
ddHiFi TC35ALUSB dongle$46156 mW+31 dBComfortable
ddHiFi TC35AirUSB dongle$46156 mW+31 dBComfortable
Fosi Audio N3Bluetooth receiver$50103 mW+29 dBComfortable
Hidizs SD2USB dongle$5052 mW+26 dBComfortable
iFi GO linkUSB dongle$5954 mW+26 dBComfortable
Kiwi Ears Allegro ProUSB dongle$6051 mW+26 dBComfortable
ddHiFi TC35Pro (Mountain2)USB dongle$6648 mW+26 dBComfortable
DUNU DTC 480USB dongle$7048 mW+26 dBComfortable
EPZ TP35 ProUSB dongle$7083 mW+28 dBComfortable
Aiyima A2 Prodesktop DAC/amp$75112 mW+29 dBComfortable
ddHiFi TC35Pro (Eye2)USB dongle$7648 mW+26 dBComfortable
ddHiFi TC44 Pro E2USB dongle$99186 mW+32 dBComfortable

The three ways a source goes wrong

Hiss. At 122.7 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 31 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.

Output impedance. At 43Ω these want a source output impedance below 5.38Ω to satisfy the one-eighth rule; 34 of the 192 sources that publish one miss it. Check yours here.

Similar headphones

Compared with its stablemates: vs DN-142 · vs Falcon Ultra · vs Vulkan 2.

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