The Audeze LCD-4 is 200Ω at 97.0 dB/mW; the Audeze MM-520 is 18Ω at 102.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The LCD-4 needs 5.0 dB more than the MM-520 to reach the same loudness — 2.0 mW against 0.63 mW.
| Specification | LCD-4 | MM-520 |
|---|---|---|
| Impedance | 200 Ω | 18 Ω |
| Sensitivity | 97.0 dB/mW | 102.0 dB/mW |
| Sensitivity (voltage) | 104.0 dB/V | 119.4 dB/V |
| Power for 100 dB | 2.0 mW | 0.63 mW |
| Voltage for 100 dB | 0.63 V | 0.11 V |
| Current for 100 dB | 3.2 mA | 5.9 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 25.00 Ω | 2.25 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
19 sources are low enough in output impedance for the LCD-4 under the one-eighth rule but not for the MM-520 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 16 more).
1 source stays below the audible-hiss threshold with the LCD-4 but crosses it with the MM-520 (Schiit Mjolnir 3).
280 of the 280 sources here reach 100 dB on both.
The LCD-4 is more demanding than 92% of the 567 non-electrostatic models in this database; the MM-520 than 35%.
| dB SPL | LCD-4 power | LCD-4 voltage | MM-520 power | MM-520 voltage |
|---|---|---|---|---|
| 80 | 0.02 mW | 63 mV | 6.3 µW | 11 mV |
| 85 | 0.06 mW | 0.11 V | 0.02 mW | 19 mV |
| 90 | 0.20 mW | 0.20 V | 0.06 mW | 34 mV |
| 95 | 0.63 mW | 0.36 V | 0.20 mW | 60 mV |
| 100 | 2.0 mW | 0.63 V | 0.63 mW | 0.11 V |
| 105 | 6.3 mW | 1.12 V | 2.0 mW | 0.19 V |
| Source | Price | Headroom, LCD-4 | Headroom, MM-520 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 3.8 dB | 14.3 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 12.1 dB | 25.7 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR11 | $36 | 3.6 dB | 18.2 dB | 0.5 Ω | 8.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 69 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 69 is the JadeAudio JA11, at $20. It leaves 3.8 dB of headroom on the LCD-4 and 14.3 dB on the MM-520, its output impedance is 0.5 Ω against a one-eighth limit of 25.00 Ω and 2.25 Ω, and its noise figure puts the hiss floor 31 dB and 16 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| LCD-4 | 5Hz - 50kHz | not printed | not printed |
| MM-520 | 5Hz - 50kHz | not printed | not printed |
Audeze prints the same thing for both the LCD-4 and the MM-520: 5Hz - 50kHz.
Neither range has a tolerance printed beside it, so the matching numbers say little.
Not a measurement; maker by maker.
Both have a page of their own. In full: Audeze LCD-4 and Audeze MM-520. Every figure on this page comes from what Audeze published, or is derived from it — what that maker publishes, counted.