Reviewed on: SoundStage! Solo, March 2023
I measured the Sennheiser Momentum 4 headphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and an Audiomatica Clio 12 QC audio analyzer. A Reiyin WT-HD06 Bluetooth transmitter was used to send signals from the Clio 12 QC to the headphones. A Samsung Galaxy S10 smartphone served as a source for certain measurements. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. 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.
This chart shows the Momentum 4 headphones’ frequency response in Bluetooth mode with noise canceling on full. There’s nothing really out of the ordinary here. The left- and right-channel measurements don’t match all that well; this could be the result of the gating needed to overcome Bluetooth’s latency, but I tried many times to get them to match, and couldn’t.
This chart (done using the Clio’s FFT function with white noise, so it looks somewhat different) shows the difference in response with the noise canceling on and off, Transparency mode, and with a wired connection with power off. Admirably, the noise canceling has no effect on the frequency response. However, Sennheiser doesn’t seem to have put any work into acoustical tuning, because the wired response with power off (which can’t exploit the internal digital signal processing) is a mess—adequate for plugging into an airplane seat and watching old Seinfeld episodes, but not in any case where you care about what the material sounds like.
This chart shows the Momentum 4 headphones’ response compared with a few competitors, all in Bluetooth mode with noise canceling on—except for the AKG K371s, which I’m using as a Harman curve proxy. The Momentum 4s seem a little light in the midrange, but otherwise largely in the ballpark with other good noise-canceling headphones.
The Momentum 4 headphones’ right-channel spectral-decay plot (measured with the wired connection) has a bit of resonance in the bass, but it’s well-damped and basically gone in a few milliseconds.
Here’s the THD vs. frequency, measured using the wired connection at 90dBA and 100dBA (both levels set with pink noise). The distortion gets pretty high in the bass, but only at extremely loud levels, and bass distortion is much less audible because the distortion harmonics are well below the human ear’s range of greatest sensitivity.
In this chart, the external noise level is 85dB SPL (the red trace), and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. I threw in the Momentum 4s’ Transparency mode, which, strangely, doesn’t seem to let in much sound above 1kHz. The Momentum 4s’ noise canceling isn’t the best, but it’s pretty close to the best.
Note that the transmitter showed it was in aptX Low Latency mode. The headphones are equipped with aptX and aptX Adaptive.
The impedance magnitude, measured in wired mode with power off, measures about 75 to 80 ohms up to 1kHz, and then falls to a minimum of about 52 ohms, with a corresponding electrical phase shift.
Sensitivity with the wired connection, power off, averaged between 300Hz and 3kHz, with a 1mW signal calculated for the rated 80 ohms impedance, is 105.6dB, plenty high enough to get loud levels from any source.
Bottom line: The Momentum 4 headphones’ measured performance looks good, with a pretty safe and sane frequency response and very good noise canceling. The only sore spot is the wackadoodle frequency response in wired/power-off mode.
. . . Brent Butterworth
brentb@soundstagenetwork.com