Audeze LCD-5 vs HiFiMAN Sundara: which needs more amplifier?

The Audeze LCD-5 is 14Ω at 90.0 dB/mW; the HiFiMAN Sundara is 32Ω at 92.0 dB (no reference unit printed). This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.

The Audeze LCD-5 needs 2.0 dB more than the HiFiMAN Sundara to reach the same loudness — 10 mW against 6.3 mW.

The numbers that decide it

SpecificationAudeze LCD-5HiFiMAN Sundara
Impedance14 Ω32 Ω
Sensitivity90.0 dB/mW92.0 dB
Sensitivity (voltage)108.5 dB/V106.9 dB/V
Power for 100 dB10 mW6.3 mW
Voltage for 100 dB0.37 V0.45 V
Current for 100 dB26.7 mA14.0 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.75 Ω4.00 Ω
Sources that reach 100 dB
out of 280
274280

One caution before reading the rows. HiFiMAN Sundara printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, that model needs far more than the table says. Why the two readings differ by so much.

Where the two part company

6 of the 280 sources have the power for the HiFiMAN Sundara but not for the Audeze LCD-5 — Apple USB-C dongle (EU), Zoom AMS-22, Steinberg UR22C, 3 more.

4 sources are low enough in output impedance for the HiFiMAN Sundara under the one-eighth rule but not for the Audeze LCD-5 (Schiit Vali 2+, Astell&Kern HC3, RME Fireface UFX II, 1 more).

274 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.

Both pages in full

Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Audeze LCD-5 and HiFiMAN Sundara. Each figure on this page is labelled on those pages with where it came from, including the ones Audeze and HiFiMAN never published — what Audeze publishes and what HiFiMAN publishes, both counted.