Razer Kraken Pro V2 impedance and sensitivity: what «118 ± 3 dB» costs on a Tascam US-2x2HR
Loud enough for everyday listening, with little spare for peaks. The US-2x2HR reaches about 105.9 dB on the Kraken Pro V2. Those are the published figures.
The Tascam US-2x2HR will play the Razer Kraken Pro V2 loudly enough for most days. What you do not have is a comfortable reserve when the music suddenly gets much louder.
The Kraken Pro V2 is 32 Ω. Reaching a 110 dB peak — a loud moment in film or classical, not a casual average — takes about 0.40 V from the source. The US-2x2HR gets to 105.9 dB on this load.
Separately, the output impedance is 66 Ω into 32 Ω headphones. On a dynamic driver that ratio can lift or dull the bass. It is a note about tone, beside the loudness result, not a replacement for it.
On compressed pop you will not notice. On classical or a film mix the volume control will sit high. Buy a headphone amp if you want those peaks clean. Do not buy one because someone said every 32 Ω headphone is impossible from an interface — that is not what this pair does.