COSMO vs PARA 2: which needs more amplifier?

The Moondrop COSMO is 15Ω at 81.8 dB/mW; the Moondrop PARA 2 is 9Ω at 85.5 dB/mW. 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 COSMO needs 3.7 dB more than the PARA 2 to reach the same loudness — 66 mW against 28 mW.

The numbers that decide it

SpecificationCOSMOPARA 2
Impedance15 Ω9 Ω
Sensitivity81.8 dB/mW85.5 dB/mW
Sensitivity (voltage)100.0 dB/V106.0 dB/V
Power for 100 dB66 mW28 mW
Voltage for 100 dB1.00 V0.50 V
Current for 100 dB66.4 mA56.0 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.88 Ω1.12 Ω
Sources that reach 100 dB
out of 280
188223

Where the two part company

35 of the 280 sources have the power for the PARA 2 but not for the COSMO — FiiO SnowSky Tiny B, Fosi Audio N3, Truthear SHIO, 32 more.

8 sources are low enough in output impedance for the COSMO under the one-eighth rule but not for the PARA 2 (FiiO KA13, FiiO K11, Schiit Vali 2+, 5 more).

188 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: Moondrop COSMO and Moondrop PARA 2. Every figure on this page comes from what Moondrop published, or is derived from it — what that maker publishes, counted.