I would be extremely interested in, and open to, hearing any/all thoughts regarding the determination of a headphone amp's driving potential & adequacy in meeting headphone driver requirements via equipment specs and scientific calculation.

A.) AudioQuest DragonFly Black - Power Output (Vmax) & Impedance: 1.15 Vrms (3.25 Vp-p) @ 0.3 ohms

B.) Nhoord Red v2 - Impedance & Sensitivity: 32 ohms @ 95 db/mW SPL (110 dB/V SPL)

i.) Best Amp Output Impedance for the Nhoord Red v2 by the “1/8th rule”: 1/8 * 32 ohms = <4 ohmsThe DragonFly Black’s integrated headphone amplifier delivers a maximum voltage of 1.15 V per channel @ 0.3 ohms. This corresponds to a output power of 2×41.33 mW @ 32 Ohms driving the Nhoord Red v2s up to 111 peak db SPL.

ii.) DragonFly Black Power Output with Nhoord Red v2: (1.15 Vmax * 1.15 Vmax)/32 ohms = 41.33 mW (Pmax)

iii.) SPL from Power for Nhoord Red v2 & DragonFly Black: 95 dB/mW + 10 * LOG (41.33 mW) = 111 peak dB SPL

iv.) SPL from Voltage for Nhoord Red v2 & DragonFly Black: 110 dB/V + 20 * LOG (1.15 Vrms) = 111 peak dB SPL

If I am not mistaken the norm is to have around 105-110 dB SPL... unless, that is, one listens loudly (potentially unhealthy listening levels) to uncompressed audiophile recordings of dynamic classical pieces, then one may need up to 115-118 dB for headroom purposes correct? So, is 111 SPL sufficient? If not, where would the driver response be most effected? In the low end?

What other measurements and specifications should one take into account and why?

Frequency Response of Nhoord Red v2 Drivers "Alone - Outside of Cup"