Headphone Reviews

Raw frequency response plots for the active wired mode show a remarkably flat and subtly tuned response from 10Hz to around 800Hz. Bass response shows a very gentle rise starting at about 400Hz to its shelf level at 60Hz around 5-6dB over baseline. It would be very hard to get this shape through purely acoustic means, and I found it particularly pleasing. This is why active DSP headphones in the future may begin to sonically outperform passive headphones. Bass was wicked tight and extended for any headphone at this price.

The run-up from 600Hz to 3.5kHz moves all over the place with changes in headphone position. I think this has to do with the DSP algorithms changing the sound as the interior microphones hear thing a little differently as the pinna moves around in the ear cup. You'll notice in the passive mode plots later on this page that there is not nearly the movement in this area with the DSP off.

The actual tuning in this area is a little hard to see with the lines all over the place, but I see a pattern that looks an awful lot like the measurements I took at Harman. I felt the QC35 was just a bit laid back in this area, but quite good otherwise.

The treble response doesn't look too bad, but for a bit of a herky-jerky nature. Tonal response when listening seem good, but as you can see in the 300Hz square wave there's a bit of a harsh transient response with a stron second edge.

30Hz square wave response has good shape, the slight forward shoulder indicating the mild bass boost. Little downward sway means little phase distortion. You'll notice the distortion plot, though a little wonky looking, remain below 1% throughout the bass. This thing has great bass!

300Hz square wave does have the previously mentioned jagged leading edge, which can also be seen as a strong second bump in the impulse response. Wave shape overall however is nicely horizontal showing the even treble tonality heard.

Distortion above 1kHz kind of whacky but not too terribly high. I suspect we're seeing the DSP in action fighting the good fight but farting a bit along the way. Most noise cancelers have weird distortion plots...that's the way it goes.

Impedance and phase plots are meaningless as we're just looking into the input of the electronics.

Isolation plot shows better than -20dBr almost throughout. This is near IEM levels...this is excellent isolation.

With 121mVrms needed to achieve 90dB at the ear this headphone doesn't play as loud as many with a smartphone but it does get to solid levels. It does play louder in Bluetooth mode.

With a careful look at the differences in the bass and treble, you can see the Bluetooth measurement here had a bit more of each than the wired active mode plots. I think this is because I had the headset setting on a medium level when I took the measurements and the Volume Optimized EQ was putting a little Fletcher-Munson in the mix.

No other noteworthy differences. The QC35 sounds very similar in BT and active wired modes other than the Volume Optimized EQ.

Passive mode raw plots show a fairly dramatic difference from active mode with DSP. Bass rolls off fairly quickly below 60Hz. There's a honky bump in the midrange centered at 800Hz. Peak at 3.5kHz is too high. Jaggity treble in about the right place. Overall balance is good—not too warm, not too bright. But it's clearly a bit of a rough response in listening. It's meh...but I'd listen to it if I ran out of juice.

30Hz square wave goes out of phase. 300Hz square wave is all jaggity, as is the impulse response. Distortion is not bad but a bit goofy. Note 100dBspl low bass is more distorted in passive mode than in active modes.

I'll not belabor the point, these are mediocre but listenable.