Sidebar 3: Measurements
I didn't measure the Audezes' frequency response, as I don't have the necessary simulated head and torso, and estimating the optimal response of headphones is far from simple (footnote 1). However, I used my Audio Precision System One to measure the Audeze LCDi4s' impedance and electrical phase. The solid trace in fig.1 shows the impedance magnitude with the headphones inserted in my ears. The impedance is a constant 26.7 ohms across the audioband, and the phase angle is 0° up to 10kHz, suggesting that the planar-magnetic drive-unit behaves as a pure resistor up to 10kHz, with the slightly positive angle above 10kHz due to its residual inductance.—John Atkinson
Footnote 1: See Sean Olive, Todd Welti, and Elisabeth McMullin, "Listener Preferences for Different Headphone Target Response Curves," presented at the May 2013 AES Convention; downloadable from www.aes.org/e-lib/browse.cfm?elib=16768. See also my colleague Tyll Hertsens's recent thoughts on this subject here.
Fig.1 Audeze LCDi4, electrical impedance (solid) and phase (dashed) when inserted in JA's ears (5 ohms/vertical div.).
Footnote 1: See Sean Olive, Todd Welti, and Elisabeth McMullin, "Listener Preferences for Different Headphone Target Response Curves," presented at the May 2013 AES Convention; downloadable from www.aes.org/e-lib/browse.cfm?elib=16768. See also my colleague Tyll Hertsens's recent thoughts on this subject here.
