The Softears RSV is 8Ω at 104.0 dB/mW; the Softears Twilight is 16Ω at 105.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The RSV needs 1.0 dB more than the Twilight to reach the same loudness — 0.40 mW against 0.32 mW.
| Specification | RSV | Twilight |
|---|---|---|
| Impedance | 8 Ω | 16 Ω |
| Sensitivity | 104.0 dB/mW | 105.0 dB/mW |
| Sensitivity (voltage) | 125.0 dB/V | 123.0 dB/V |
| Power for 100 dB | 0.40 mW | 0.32 mW |
| Voltage for 100 dB | 56 mV | 71 mV |
| Current for 100 dB | 7.1 mA | 4.4 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 1.00 Ω | 2.00 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.
12 sources are low enough in output impedance for the Twilight under the one-eighth rule but not for the RSV (FiiO KA13, FiiO K11, Schiit Vali 2+, 9 more).
6 sources stay below the audible-hiss threshold with the Twilight but cross it with the RSV (Lake People G103-S Mk II, Schiit Valhalla 3, Lake People G111 Mk II, 3 more).
280 of the 280 sources here reach 100 dB on both.
The Twilight is more demanding than 22% of the 567 non-electrostatic models in this database; the RSV than 14%.
| dB SPL | RSV power | RSV voltage | Twilight power | Twilight voltage |
|---|---|---|---|---|
| 80 | 4.0 µW | 6 mV | 3.2 µW | 7 mV |
| 85 | 0.01 mW | 10 mV | 0.01 mW | 13 mV |
| 90 | 0.04 mW | 18 mV | 0.03 mW | 22 mV |
| 95 | 0.13 mW | 32 mV | 0.10 mW | 40 mV |
| 100 | 0.40 mW | 56 mV | 0.32 mW | 71 mV |
| 105 | 1.3 mW | 0.10 V | 1.0 mW | 0.13 V |
| Source | Price | Headroom, RSV | Headroom, Twilight | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 12.8 dB | 16.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 24.9 dB | 28.9 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 21.8 dB | 25.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 55 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 55 is the JadeAudio JA11, at $20. It leaves 12.8 dB of headroom on the RSV and 16.8 dB on the Twilight, its output impedance is 0.5 Ω against a one-eighth limit of 1.00 Ω and 2.00 Ω, and its noise figure puts the hiss floor 10 dB and 12 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| RSV | 5-40kHz | not printed | not printed |
| 20-20kHz | not printed | not printed | |
| Twilight | 8-40kHz(1/4' free field，-3dB) | -3 dB | 1/4″ free field |
| 20-20kHz（IEC60318-4） | not printed | IEC60318-4 |
Softears prints two ranges, “5-40kHz” and “20-20kHz”, for the RSV and two ranges, “8-40kHz(1/4' free field，-3dB)” and “20-20kHz（IEC60318-4）”, for the Twilight.
Only one of the two is a specification. The range printed for the Twilight comes with a tolerance; the one printed for the RSV does not, and a range without a ±dB figure says nothing about how loud that model is at either end of it. The two cannot be compared number against number, however similar they look in the table. Of the 490 models whose maker prints a range, 58 print the tolerance.
Not a measurement; maker by maker.
Both have a page of their own. In full: Softears RSV and Softears Twilight. Every figure on this page comes from what Softears published, or is derived from it — what that maker publishes, counted.