Sennheiser PMX686i


Tech Specs

  • Impedance: 30 Ω
  • Freq response: 18–20,000 Hz
  • SPL: 120 dB (1 kHz/1 Vrms)
  • Total Harmonic Distortion: <0.5%
  • Jack plug: 3.5mm, straight
  • Cable length: 1.2m single-sided
  • Pick-up pattern: Omnidirectional
  • Sensitivity: (121TR 9-5) –44dB V/Pa


Enjoy remarkable stereo sound even during outdoor sports with the Sennheiser PMX686i SPORTS headphones whether you are running uphill or sprinting for the finish.

Innovative Design

Built to remain securely in place, the innovative in-ear design enables you to still hear what goes on around you as you listen to your favourite tunes. The Sennheiser PMX 686i sports features an inline smart remote and mic on the cable, which are compatible for iOS devices.

Build and design

The band won’t be ideal for all exercise – it might get in the way during floor work, gym-goers – but otherwise, does the job it’s cut out for: keeping the buds stable and secure on your head. It’s conveniently light and flexible for a universal fit, and the old-school plastic buds spring into your ears with little encouragement.

The Sennheisers are comfortable for the most part, though we found the buds’ minimal rubber coating a little hard on the ears an hour into a workout. Not everyone will be convinced that they look their price: the plastic frame is rather plain and embellishment doesn’t go beyond a tiny Adidas logo.

Yet, we don’t mind when the performance is so good. It’s hard to pick holes in their sound; a rich, weighty presentation is rare at this price, but the Sennheisers pull it off.

Comfortable Fit

Maximum ruggedness and durability means the earphones are sweat and water-resistant, the Vertical in-ear design offers better situational awareness and safety. With antimicrobial ear adapters (SteriTouch) and an ultra-lightweight neckband, the Sennheiser PMX686i’s ensure a secure and comfortable fit.

Features Sennheiser PMX686i

The single-sided 1.2m cable is practical for not getting caught up in wires, but less so is the layout of the 3-button in-line remote: the buttons are squashed closely together, so it’s hard to differentiate between them without looking – once mounted, the remote is too close to your ear to see the buttons. Puzzling.

You’re best learning the functions (the main ones being press the middle-button once to play/pause, twice to skip forward a track, thrice to go back) before use. You can also fast-forward and rewind through a song, and achieve simple call operations.

The shiny plastic Adidas-branded velcro-bag (much like the drawstring sports bags of the 90s) is a useful bonus for keeping them protected between training sessions.

Tangle Free

Para-aramid-reinforced cable provides superior strength and reliability while the oval-shaped cable ensures a tangle-free listening experience with reduced cable noise. The headphones are supplied with a convenient storage pouch and cable clip.

Voice Quality

If you are not going to do intense exercise or feel that it will be an acceptable fit for your head size, good sound performance at this price is a hefty bonus. Regarding sound, numerous tests reveal that the headset smoothly filters out high volume noise from trains, traffic and television. In fact, there are no visible degradation or distortion when sound is raised from low to high.

Still, it does not mean that the headphone are able to cancel noise like their pricier counterparts. There will be some noise in and out of the microphone, depending on the volume and the environment. It should also be noted that people who are accustomed to very high levels of sound quality may be distracted because the sound levels does not match the pricier counterparts. Still, this is some of the best sound quality that you can get for the price.

Sennheiser PMX686i Sound Quality

I’ve got to be honest here: I found these so uncomfortable that I didn’t listen to nearly as much music through them as I normally would, but we did run them through the usual gamut of testing. As you’ll see, I had almost no issues with the sound, but I felt compelled to shine a light on this deviation from our usual testing procedures.


Given the fit and the fact that the earbuds don’t create a seal in your ear, I was surprised at the bass response. Lows are powerful, but some of the bass does encroach on the midrange. The low end feels almost artificial — as if there is some sort of processing going on – but that obviously isn’t the case in passive headphones.

Sennheiser PMX686i Mids

The midrange is loud and powerful, with the snap of snare drums and the growl of electric guitars well represented here. Vocal detail was preserved nicely on Speedy Ortiz’s “The Graduates,” but the guitars on Chavez’s “Break Up Your Band” were somewhat overshadowed by the drums and bass.


The highs have a somewhat strangled sound to them that I couldn’t quite put my finger on, though I can say that they definitely taper off a bit. There isn’t any harshness, but it feels like the Sennheiser PMX686is are playing it overly safe in the high end.

Stereo imaging is nice, and there is a nice spacious sound that I don’t expect out of this form factor. The noise isolation isn’t great, but it is better than I would have imagined given the way these fit. With no music playing, you can hear what’s going on around you find, but even at lower volumes they do a fairly good job of blocking out background noise.