Sennheiser PXC 250-II

Design

As you can see, the two headphones have slightly different designs. The QC15s are over-ear headphones with an active noise cancellation feature that requires a single AAA battery. The PXC 250-IIs are a set of in-ears with no fancy-pants cancellation, and, as in-ears, are significantly more fragile than the QC15s.

Sennheiser PXC 250-II	Bose QuietComfort 15

Frequency Response

The PXC 250-IIs have a much more even frequency response. Look at those scribbles on the QC15s’ graph.

Sennheiser PXC 250-II	Bose QuietComfort 15

Distortion

The QC15s have more distortion than the PXC 250-IIs. You might think it’s because the QC15s won’t work without their active cancellation feature enabled, which creates distortion. Even with its active cancellation switched on, however, the PXC 250-IIs aren’t as bad.

Sennheiser PXC 250-II	Bose QuietComfort 15

Tracking

The QC15s have some tracking wobble in the high end, but the PXC 250-II meanders a bit in the low end.

Sennheiser PXC 250-II	Bose QuietComfort 15

Isolation

Say what you will about Bose: boy oh boy does their active cancellation feature work.

Sennheiser PXC 250-II	Bose QuietComfort 15

Comfort

The PXC 250-IIs and QC15s are both very, very comfortable. The QC15s have a higher potential of getting a bit heavy over time, but their circumaural cups are probably a bit more comfortable than the PXC 250-IIs’ small on-ear cups.

Wear
Sennheiser PXC 250-II	Bose QuietComfort 15

Verdict

The PXC 250-IIs are better for audio quality or portability, but if you’re taking your headphones anywhere noisy, the QC15s are by far the better option.