The Symphonium Giant is 7.0Ω with a sensitivity of 88.5 dB/mW, which is 110.0 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 14 mW, or 0.31 V across the drivers.
That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 109 have at least 10 dB of headroom and another 88 have enough. The cheapest portable source that does the job is the FiiO SnowSky Tiny B at $22.
Sensitivity here is in dB per milliwatt. Why the unit matters.
Symphonium publishes this as 110 dB/Vrms (@ 1 kHz) — a figure per volt, not per milliwatt. At 7.0Ω the two differ by 21.5 dB, so the 88.5 dB/mW above is that published number converted, not a different measurement.
This is the conversion that online calculators skip. Quote the per-volt number as if it were per-milliwatt and this headphone looks 22 dB easier to drive than it is — which is roughly the difference between a dongle being enough and not being enough.
Symphonium prints the impedance as 7.0 Ohms @ 1 kHz, not as a bare number. Everything on this page is calculated with the nominal 7.0Ω, and the rest of that line is quoted here rather than tidied away, because how a figure is qualified is part of the specification too.
Source: symphoniumaudio.com. How this data was built.
| As it is labelled | As printed | Tolerance | Standard |
|---|---|---|---|
| Frequency Response | 5Hz - 18kHz, ± 2 dB | ±2 dB | not printed |
Symphonium prints 5Hz - 18kHz, ± 2 dB for the Symphonium Giant, under the heading “Frequency Response”. Source: symphoniumaudio.com.
This is one of only 58 models — out of the 490 whose maker prints a range at all — that also print the tolerance. That is what makes it a specification rather than a headline.
Only what the maker printed; maker by maker.
| Level | What it is | Power | Voltage | Current |
|---|---|---|---|---|
| 85 dB SPL | quiet background listening | 0.45 mW | 56 mV | 8.0 mA |
| 95 dB SPL | normal listening | 4.5 mW | 0.18 V | 25.3 mA |
| 100 dB SPL | loud listening | 14 mW | 0.31 V | 44.9 mA |
| 105 dB SPL | very loud | 45 mW | 0.56 V | 79.9 mA |
| 110 dB SPL | peaks on dynamic music | 141 mW | 0.99 V | 142.1 mA |
Most people listen between 75 and 85 dB; the 100 dB row leaves room for peaks.
The 15 cheapest of the 280 sources here that reach 100 dB SPL into 7.0Ω with at least 10 dB of headroom and no known hiss or output-impedance problem with these headphones. All 280 sources, judged for these headphones.
| Source | Type | Price | Power into 7.0Ω | Headroom | Verdict |
|---|---|---|---|---|---|
| JDS Labs Atom+ (2nd gen) | desktop amplifier | $99 | 219 mW | +12 dB | Comfortable |
| Schiit Magni Heresy | desktop amplifier | $99 | 1.2 W | +19 dB | Comfortable |
| Schiit Magni+ | desktop amplifier | $109 | 438 mW | +15 dB | Comfortable |
| Schiit Magni Unity | desktop amplifier | $119 | 1.3 W | +20 dB | Comfortable |
| JDS Labs Atom Amp 2 | desktop amplifier | $129 | 580 mW | +16 dB | Comfortable |
| Schiit Vali 3 | desktop amplifier | $149 | 328 mW | +14 dB | Comfortable |
| Topping L30 II | desktop amplifier | $149 | 1.5 W | +20 dB | Comfortable |
| SMSL HO100 | desktop amplifier | $160 | 1.3 W | +20 dB | Comfortable |
| Shanling H2 | portable amplifier | $169 | 149 mW | +10 dB | Comfortable |
| xDuoo MT-604 | desktop amplifier | $169 | 438 mW | +15 dB | Comfortable |
| TempoTec Variations V3 Blaze | portable player | $179 | 180 mW | +11 dB | Comfortable |
| iFi Zen CAN | desktop amplifier | $199 | 350 mW | +14 dB | Comfortable |
| Geshelli Archel Pro | desktop amplifier | $200 | 394 mW | +14 dB | Comfortable |
| Schiit Magni Piety | desktop amplifier | $200 | 525 mW | +16 dB | Comfortable |
| SMSL C200 | desktop DAC/amp | $219 | 1.1 W | +19 dB | Comfortable |
Hiss. At 110.0 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 18 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.
Output impedance. At 7.0Ω these want a source output impedance below 0.88Ω to satisfy the one-eighth rule; 87 of the 192 sources that publish one miss it. Check yours here.
6.1Ω · 85.9 dB/mW · Moderate
See requirements →6.05Ω · 83.8 dB/mW · Moderate
See requirements →8.3Ω · 86.2 dB/mW · Easy
See requirements →32Ω · 96.0 dB · Easy
See requirements →30Ω · 93.8 dB/mW · Easy
See requirements →45Ω · 98.0 dB/mW · Easy
See requirements →Compared with its stablemates: vs Crimson · vs Helios · vs Titan · vs Triton · vs Zenith.