Sanctuary with the Sennheiser Momentum Wireless M2 AEBT Measurements

Measurements
Wired Passive
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Wired Active

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Bluetooth Active

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As we go through this you may want to have a look at measurements of the original Sennheiser Momentum; Parrot Zik 2 active and passive; Beats Studio 2 Wireless; and Bose Quiet Comfort 25 active and passive.

Let's first talk about the M2 in wired passive mode, and compare it to the original Momentum. One thing you will notice with a quick peruse of the plots is there are a lot of similarities here. The general shape of the frequency response plots are similar, and both have a deep notch at about 4.3kHz. The M2 does rise in the bass more, and also rises from 300Hz to 3kHz more steeply. The M2 looks a little closer to the target curve to me, but in listening I found that because the bass was somewhat loose and the accentuation in the presence area strong, that the mid-range in between felt a bit left out. Also, on both headphones, the treble above 3kHz is a little too rolled-off. With the old Momentum having a rather flat curve this the top end roll-off doesn't feel so severe, but with the M2 the accentuation at 3kHz made the roll-off seem more extreem. As a result I found myself more aware of the presence region and looser bass, where the old Momentum sounded significantly more even.

The notch at 4.3kHz wasn't audible to me, and it does create a narrow distortion spike, which is also likely not a problem.

Square wave shapes are similar with the old Momentum showing less swayback on the 30Hz square wave indicative of it's tighter bass. Leading edge of the 300Hz square waves on both cans are a little slow indicative of the relaxed treble response; the overshoot is a little bigger on the M2 probably due to the more emphasized presence region. Impulse response shows that the M2 is out of absolute polarity.

Impedance of the M2 is 6 Ohms higher than the old Momentum at around 28 Ohms. Isolation is pretty good for a passive sealed can at -18dB broadband.

Now, moving on to active modes, the first thing to notice is the M2 shows virtually identical performance in wired and Bluetooth modes with the exception of the 30Hz square wave shape. Because I see no difference in the frequency response or bass distortion, I think we're just seeing an artifact of the noise canceling, which can do some odd things at low frequencies. If you look closely you'll see that the BT raw frequency response plots has one measurement that is a little above the rest at 30Hz. That difference could certainly be responsible for the difference in wave shape between the two sets of measurements. So, I'd suggest we assume the unit measures the same wired and BT, and we can put away the BT graph.

Comparing the M2 passive to active now, the first thing we notice is an imbalance between the left and right channel. I did try to listen for this imbalance and did not hear it. This too might be an artifact from the noise canceling and the proximity of the headphone to the sidewalls in the chamber. I have seen some weird things when measuring noise cancelers.

Raw frequency response plots clearly show the rise to 2kHz is much steeper when the M2 is active, which brings out that upper mid-range/lower-treble presence region. To me the headphones sounded quite a bit harder as a result. The bass response also significantly changes shape, and I heard it as less emphatic and tighter. You can also see that while the distortion is higher overall, the distortion doesn't rise in the bass as it does when run active. Response above the notch at 4kHz is about the same in both modes. Generally speaking, although lower in level than ideal, I never had any problem with stridency or harshness in the treble with the M2 in any of its operating modes.

300Hz square wave is pretty angry looking with that big overshooting spike, but I think that's do to the emphasis at 3kHz and below so it isn't piercing as narrower spikes can sound. Still, the presence region is strong with the M2.

The distortion plot is pretty ugly as well, I did notice the headphones getting harder sounding as the volume goes up. The Zik2 and Bose fair better here, but the Beats Studio 2 is clearly worse.

Now let's compare the FRs of the Zik 2, Beats Studio, Bose QC25, and the M2 in active modes. The QC25 is a bit closer to target than the M2, but not much. The Zik 2 is a bit weird in the treble, but at least you can EQ it with its app. The Beats is a train wreck. Also have a look at all the 300Hz square wave plots, all but the M2 are ringing pretty severely.

Moving on to the all-important, in this case, isolation plot; this is where your money is going with these cans, isolation should be weighed heavily. The Bose, Zik 2, and Sennheiser are quite good, with the QC25 and Zik 2 just edging out the M2 with a bit better very low frequency isolation and a broadband attenuation of -27dB vs. -24dB for the M2. The beats don't do well in the middle frequencies.

Now lets look at the passive plots of the Zik 2 and QC25 compared to the M2, and you'll see the M2 is superior again in just about every way.

My take is that when you look at the measurements of the Zik2 and Beats—the only two that are Bluetooth and noise canceling—the Momentum Wireless M2 is clearly superior.

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