The Very Adult Sennheiser Momentum Measurements
Raw frequency response plots show a headphone with few peaks and vallies in the treble response and little in the way of change in the seal in the lows. This headphone should be fairly stable in its sound with any positional changes on the ear.
Compensated frequency response shows only mild deviation from flat from 10Hz to 2kHz. This is quite a good showing. Treble response from 5kHz to 15kHz is remarkably flat, though probably 3-5dB lower than what I suppose perfectly neutral would be. None the less, the lack of peaks and vallies in the treble is quite unusual and I would assume positive. It's interesting to note the deep notch at 4.5kHz. I wonder what roll it plays...Sennheiser engineers don't do things for no good reason?
30 Hz square wave shows very good shape, probably the best I've seen for a sealed headphone. The slight bowing of the square wave top and the rise in THD below 100Hz indicates a slight lack of bass tightness. This is still and excellent result for a sealed headphone, however.
The 300Hz square wave shows a slightly slow rise time, but nicely controlled first overshoot. Some fairly modest ringing of the headphones can be seen after the first overshoot, and in the nicely shaped but also slightly ringing impulse response. These probably indicate the slight glare heard in listening tests, but also show that the problem is fairly minor compared to many headphones.
The impedance plot shows a fairly constant roughly 23 Ohm impedance over the frequency response range. The phase response is likewise well behaved. Isolation is somewhat above average for a headphone of this type. These factors coupled with 22mVrms required for 90dBspl make this a fairly ideal portable headphone.
These measures indicate to me that the Sennheiser engineering team were hitting on all twelve cylinders when they designed these cans. This is evidence of a mature engineering group who know exactly what they're on about.