Sennheiser CX 680i

Design

The hf3 headphones might look a bit boring, but we’re sure they’d prefer the term “minimalistic.” The main difference between the two isn’t a durability issue, but rather how each implements their remote & mic. The hf3s have a better position for their remote & mic, placed high up on the left ear bud’s cable. The CX 680i’s control is a bit lower, which makes it a bit awkward if you have a bag slug between your shoulders: the strap will push its buttons. We liked the CX 680i’s button style better, however, as they’re a lot easier to use without looking. The hf3 has three identical buttons, and it’s easy to accidentally hit the wrong one.

Sennheiser CX 680i	Etymotic Research hf3

Frequency Response

The hf3s underemphasized the high end but didn’t overemphasize the low end like the CX 680is did. The hf3s also have much more consistency between their left and right channels.

Sennheiser CX 680i	Etymotic Research hf3

Distortion

No real distortion issues here, though the hf3 has slightly more in the middle of the frequency spectrum.

Sennheiser CX 680i	Etymotic Research hf3

Tracking

The hf3s have a much more even tracking.

Sennheiser CX 680i	Etymotic Research hf3

Isolation

The hf3s isolate a lot more bass than the CX 680is.

Sennheiser CX 680i	Etymotic Research hf3

Comfort

We thought both headphones were about the same in terms of comfort, though if you’re used to in-canal earphones, the hf3s will probably feel like a better fit.

Wear
Sennheiser CX 680i	Etymotic Research hf3

Verdict

This is a rough match-up since the two headphones are so similar. We’re leaning towards the hf3s on this matchup because they’re more compact, have a much more consistent audio quality, and have better placement for their remote and mic. Really, though, the differences are minor and their price point is roughly the same: try both out before making a final decision.