Razer Kraken (2019) sensitivity: 109 dB per volt or per milliwatt? On a FiiO KA13 it decides everything
Razer prints «Sensitivity (@1 kHz): 109dB» with no reference. Per volt, a FiiO KA13 arrives with 0.3 dB to spare — it plays, with nothing left. Per milliwatt, the same dongle has 15.2 dB. Razer names the unit on its other sheets, and that is how the question is settled.
Signal Chain Compatibility Matrix
Select gear and parameters for live gain, impedance and SPL calculations.
Input Equipment Setup
PASS: Optimal Signal Chain
Requires minimum +60dB of clean pre-amp gain. Most budget entry interfaces max out at +50dB to +56dB and introduce hiss at max pot. An inline preamp booster (Cloudlifter CL-1 / FetHead) is strongly recommended.
The interface preamp provides sufficient headroom.
$538
$405
-25%Tonal & acoustic characteristics: Flat, wide-range frequency response for clean music and speech. Smooth, warm acoustic character with air-suspension shock isolation.
Technical advisory: With +69dB max gain, the Gen 4 Solo can drive demanding dynamics like the Shure SM7B natively without requiring an external inline booster.
Physical Interconnect Topology
Shure SM7B
Direct Cable Connection (No Intermediate Box)
1x Shielded Balanced XLR Cable (3-Pin XLR Male to XLR Female)
Focusrite Scarlett Solo (Gen 4)
Host: Apple MacBook Pro (M1/M2/M3/M4)
On this dongle the missing unit is the difference between «it plays, with nothing to spare» and «it plays with 15 dB in hand». Same headset, same dongle, same 110 dB target.
Razer's support page for the Kraken (2019) prints, in full: «Impedance: 32 Ω @ 1 kHz» and «Sensitivity (@1 kHz): 109dB». A sound pressure level in decibels means nothing until you know what one decibel is referenced to — one milliwatt into the driver, or one volt across it.
Read per volt — how we store it. 109 dB/V needs 10^((110−109)/20) = 1.122 V to hit a 110 dB peak, which at 32 Ω is 35.06 mA and 39.34 mW. The FiiO KA13 publishes 1.22 V and an output impedance below 1.7 Ω; the divider leaves 1.158 V at the headset. Result: 110.3 dB SPL, +0.3 dB of headroom, verdict «enough, without headroom». Damping ratio 18.8, so the tonal balance is safe; it is the level that is on the edge.
Read per milliwatt. S_V = 109 + 10·lg(1000/32) = 123.95 dB/V. The same peak now needs 0.201 V, 6.27 mA and 1.26 mW. The KA13 reaches 125.2 dB SPL, +15.2 dB, verdict comfortable. The gap between the two answers is exactly 10·lg(1000/32) = 14.95 dB, and the voltage your source must produce differs by a factor of 5.6.
How to tell which Razer meant. Razer names the unit where it chooses to. The BlackShark V2 sheet says «100 dB SPL/mW, 1 kHz»; the Kaira X says «96 dBSPL/mW»; the Barracuda X says «96 dBSPL/mW@1 kHz by HATS». If the Kraken's 109 were also per milliwatt, this ordinary 50 mm headset would be 9 dB more efficient than Razer's own esports flagship — a claim Razer would have made loudly and did not. Read per volt, 109 dB/V at 32 Ω is 94.05 dB/mW, which lands exactly where the labelled Razer models sit. That is the reading we store.
The pearl: the Kraken Pro V2 page from the same support site prints 118 dB, also with no unit. On this same KA13 the Pro V2 lands at +9.3 dB and the 2019 Kraken at +0.3 dB — 9 dB apart, inside one product line, with neither figure telling you what it is measured against. Whatever Razer meant, it meant the same thing on both pages, so the ranking survives the ambiguity even when the verdict does not. That is worth remembering: an unlabelled number can still be used to compare two products of one brand, and must never be used to compare across brands.