I measured the Monoprice M1060s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, a Musical Fidelity V-CAN amp for most measurements, and an Audio-gd NFB-1AMP amplifier for the distortion measurements. On the G.R.A.S. 43AG I used the original KB0065 simulated pinna for most measurements, as well as the new KB5000 pinna for certain measurements (as noted). These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The M1060s’ frequency response is pretty standard for an open-back planar-magnetic model. I noted two anomalies. First, the response between 8 and 16kHz is lower than I’m used to seeing. For reasons discussed here, above about 8kHz, headphone frequency-response measurements are less reliable, but this measurement does jibe with what I heard in my listening tests. Second, there’s an apparent mismatch between the right and left channels between 1 and 4kHz. This is the best match I was able to get after many attempts with both the Monoprices’ left and right earpieces.
This chart shows the M1060s’ measured right-channel frequency response measured with the old KB0065 pinna (which I’ve used for years) and G.R.A.S.’s new KB5000 pinna. I’ll soon be switching to the new pinna, because it more accurately reflects the structure and pliability of the human ear. I include this mostly for future reference rather than as something you should draw conclusions from; I intend to show both measurements in every review for at least the next year before I begin using only the new pinna.
This chart shows the results of adding 70 ohms output impedance to the V-CAN’s 1-ohm output impedance, to simulate the effects of using a typical low-quality headphone amp. The difference is negligible; the M1060s’ tonal balance won’t change depending on the amp used.
This chart shows the M1060s’ measured right-channel frequency response compared with two similar $299, open-back, planar-magnetic headphone models (the Tidal Force Wave 5 and HiFiMan HE400S), plus the NAD Viso HP50, a conventional closed-back model. The M1060s have a flatter measured response than the other planar-magnetics, with more bass -- an effect that could be due to a better seal of the M1060s’ plush faux-leather pads on the ear/cheek simulator. Again, you can see that the M1060s’ response between 8 and 16kHz is comparatively soft.
The spectral-decay (waterfall) chart shows low resonance in the bass, scattered narrow resonances in the midrange, and a strong series of resonances centered at 4.5kHz. The last, while scary looking, are not surprising for an open-back planar-magnetic model, most of which show a similar resonance pattern somewhere in the upper midrange/lower treble.
The M1060s’ total harmonic distortion (THD) is about as low as I’ve measured. Planar-magnetic headphones usually do well on this test, but this is excellent even when compared to most of the other planar-magnetics I’ve measured.
In this chart, the external noise level is 85dB SPL; the numbers below that indicate the attenuation of outside sounds. (Note that I recently switched to measuring at a level of 85dB instead of 75dB; this doesn’t change the way the isolation curves look, but a level of 85dB allows me to get better measurements of noise-canceling headphones, which demand a lower noise floor.) The M1060s offer about the same isolation as most open-back models: almost none.
The M1060s’ impedance magnitude and phase are almost perfectly flat right at the rated 50 ohms, except for a little bump to 57 ohms at 4.4kHz.
The sensitivity of the M1060s, measured between 300Hz and 3kHz with a 1mW signal, is 100.5dB. That’s fairly high for planar-magnetic headphones, and means that the M1060s should deliver adequate volume from any source device.
. . . Brent Butterworth
brentb@soundstagenetwork.com