Reviewed on: SoundStage! Solo, December 2019
I measured the LCD-1 headphones using laboratory-grade equipment: a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 10 FW audio analyzer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. The headphones were amplified using a Musical Fidelity V-CAN. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
The above chart shows the LCD-1s’ frequency response, which is pretty typical for open-back planar-magnetic headphones. As usual, the response is basically flat from about 100Hz to 1kHz, then rises to a big peak at 3kHz (which corresponds with the primary human ear canal resonance). What’s perhaps a little atypical is that there’s less energy above 5kHz, relative to the 3kHz peak, than we often see with planar-magnetics, which suggests that the LCD-1s won’t be fatiguing but they might not be the airiest-sounding headphones you’ve heard.
This chart shows how the LCD-1s’ tonal balance changes when they’re used with a high-impedance (75 ohms) source, such as a cheap laptop or some cheap professional headphone amps, or some exotic tube amps. There’s almost no difference, just an increase in the bass of about 0.5dB below 50Hz when a high-impedance source is used.
This chart shows the LCD-1s’ right-channel response compared with several other relatively inexpensive planar-magnetic headphones. You can see that except above 5kHz, the LCD-1s are in the ballpark with most of the rest of them.
The LCD-1s’ spectral decay (waterfall) chart is typical for planar-magnetic headphones, with a lot of very high-Q (i.e., narrow) resonances between 2 and 5kHz. I’m told this is due to reflections between the large, flat driver and the cheek plate of the G.R.A.S. 43AG; the resonances are too narrow and too numerous to be individually discernible.
The total harmonic distortion of the LCD-1s is extremely low: only 1% at 20Hz even when the headphones are cranked up to excessively loud levels.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The isolation of the LCD-1s is negligible, as with the other open-back models shown in the chart; I included the LCD-2 Closed Backs so you can see the difference in isolation with open-back and closed-back designs.
The impedance magnitude of the LCD-1s is almost dead-flat at 14 ohms, and the phase response is similarly flat.
Sensitivity of the LCD-1s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 16-ohms rated impedance, is 99.5dB. That’s lower than you’ll get from mass-market headphones, and even lower than some planar-magnetics, but not so low that the LCD-1s are difficult for most devices to drive.
. . . Brent Butterworth