HiFiMAN Susvara: how much amplifier do you need?

The HiFiMAN Susvara is 60Ω with a sensitivity of 83.0 dB/mW, which is 95.2 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 50 mW, or 1.73 V across the drivers.

That is a demanding load — not impossible from a portable source, but you want a good one. 46 of the 53 sources have comfortable headroom, 2 are marginal and 5 fall short. The cheapest portable source that does the job is the FiiO KA11 at $30.

Sensitivity here is in dB per milliwatt. Manufacturers often quote dB per volt instead and leave the unit off, which is the single most common reason online calculators give answers that are 10–15 dB wrong. The converter explains the difference.

Most people listen between 75 and 85 dB. The 100 dB row is the one worth planning around: it gives you headroom for dynamic peaks without designing your system for a volume that would damage your hearing in under fifteen minutes. The safe listening calculator puts numbers on that.

Every source in the database, judged at 100 dB SPL into 60Ω. “Headroom” is how much power is left over above what the headphone needs — 10 dB means ten times the required power, which is what you want for dynamic peaks.

Hiss. At 95.2 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Vali 2+, would put its hiss at roughly 3 dB SPL in these headphones — faintly audible in a silent room. The hiss calculator lets you check your own amplifier's noise figure.

Volume is not the test. Plenty of weak sources will play these loud enough. What runs out first is control on bass peaks, where the current demand spikes well above the average figures in the table. If it sounds loud but soft, that is what you are hearing.

Or open the comparison tool to put any two models side by side, or browse all 316.