Solo vs Volur: which needs more amplifier?

The 64 Audio Solo is 16Ω at 100.0 dB/mW; the 64 Audio Volur is 6.3Ω at 103.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The Solo needs 3.0 dB more than the Volur to reach the same loudness — 1.0 mW against 0.50 mW.

The numbers that decide it

SpecificationSoloVolur
Impedance16 Ω6.3 Ω
Sensitivity100.0 dB/mW103.0 dB/mW
Sensitivity (voltage)118.0 dB/V125.0 dB/V
Power for 100 dB1.0 mW0.50 mW
Voltage for 100 dB0.13 V56 mV
Current for 100 dB7.9 mA8.9 mA
Highest source impedance
that leaves them alone (one-eighth rule)
2.00 Ω0.79 Ω
Sources that reach 100 dB
out of 280
280280

Where the two part company

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.

49 sources are low enough in output impedance for the Solo under the one-eighth rule but not for the Volur (FiiO SnowSky Tiny B, FiiO KA13, FiiO KA15, 46 more).

9 sources stay below the audible-hiss threshold with the Solo but cross it with the Volur (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 6 more).

280 of the 280 sources here reach 100 dB on both.

What each one needs from 80 to 105 dB

The Solo is more demanding than 40% of the 567 non-electrostatic models in this database; the Volur than 14%.

dB SPLSolo powerSolo voltageVolur powerVolur voltage
800.01 mW13 mV5.0 µW6 mV
850.03 mW22 mV0.02 mW10 mV
900.10 mW40 mV0.05 mW18 mV
950.32 mW71 mV0.16 mW32 mV
1001.0 mW0.13 V0.50 mW56 mV
1053.2 mW0.22 V1.6 mW100 mV

The cheapest source that satisfies both

SourcePriceHeadroom, SoloHeadroom, VolurOutput impedanceNoise
JadeAudio JA11$2011.8 dB10.7 dB0.5 Ω1.7 µV
FiiO KA11$2923.9 dB22.8 dB0.7 Ω1.7 µV
FiiO BTR13$5920.8 dB19.7 dB0.6 Ω1.0 µV

Of the 280 sources here, 280 reach 100 dB on both. 37 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 37 is the JadeAudio JA11, at $20. It leaves 11.8 dB of headroom on the Solo and 10.7 dB on the Volur, its output impedance is 0.5 Ω against a one-eighth limit of 2.00 Ω and 0.79 Ω, and its noise figure puts the hiss floor 17 dB and 10 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.

Try any other source.

What each sheet prints, and what it is worth

ModelAs printedToleranceStandard
Solo20 Hz – 20 kHznot printednot printed
Volur5hz – 22kHznot printednot printed

64 Audio prints 20 Hz – 20 kHz for the Solo and 5hz – 22kHz for the Volur.

Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.

Not a measurement; maker by maker.

Both pages in full

Both have a page of their own. In full: 64 Audio Solo and 64 Audio Volur. Every figure on this page comes from what 64 Audio published, or is derived from it — what that maker publishes, counted.

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