Sennheiser CX300: Pouring Music Into Your Ears

These intra-aural earphones look ordinary in their somewhat nondescript blister pack, but the CX300 is a credit to their German maker. The set comes with minimal accessories: three sets of flexible adapters in different sizes for optimum coupling with your ears. Choosing which ones to use is an important step in ensuring that you get optimum performance without discomfort.

The transducers are very compact and they're easy to insert since they don't penetrate too far into your ear canal. Removing and replacing them - if you want to attempt to communicate with the people around you, for example - is quick and easy. Yet achieving good acoustical coupling isn't difficult. Those are positive points for daily use, though there's a tradeoff in the form of somewhat reduced acoustical isolation. The cable is rather short, which is well suited to use with a portable player that you carry about your person. For use with fixed equipment or with your player sitting on some surface or other you'll need to consider getting an extension cord to avoid moving too far away and abruptly pulling the buds out of your ears, which can be disagreeably uncomfortable.

Technical Characteristics

  • Type: intra-aural
  • Frequency response: 18 Hz - 21 kHz
  • Nominal impedance: 16 ohms
  • Sensitivity: 112 dB/V
  • Cable length: 1 m
  • Plug type: angled 3.5 mm mini
  • Weight: 4 g (0.14 oz)

No Fear Of Heights

The problem with almost all intraaural earphones is limited response in the extreme high frequencies. Some very sophisticated solutions are sometimes used, but the response curve doesn't follow the upward price curve associated with such solutions. So I was surprised to see that the CX300, at least on that level, performed as well as models costing several times their price. The response was quite linear, albeit with a valley in the midrange, which gave the sound a slight "Loudness" quality, except that the treble goes back up early, with extreme high frequencies all but absent, as with all "intras."

This is a remarkable response for intraaural phones, with a high extension comparable to much more expensive models.

Like most similar earphones, the efficiency of the CX300 is high. You won't have any problem getting enough volume regardless of your player. However, the fairly low impedance means that the level won't be quite as high as the gross figure might suggest.

Efficiency: approximately 115 dB/V

Listening Test

Sennheiser's CX300 is an affordable set of intraaural earphones with especially good performance in its category. It comes with minimal accessories, but that's compensated for by its affordable price.

During listening tests, I found that it had very good bass, which is rare for an intraaural set, but also slightly intense highs that quickly become tiring, depending on your taste and what you're listening to. On the other hand, in listening too I found the high-end response better than most of the other sets I tested, with an upper part of the spectrum that wasn't too truncated. If you player has an equalizer that can do so, you might prefer listening with the highs lowered somewhat. I found that a drop a little less than 3.5 kHz improved things noticeably. As for the low bass, it was sometimes really audible, and I enjoyed that. That can vary with the player you use, but here again the earphones responded well to a little correction.

To sum up, the CX300 is not faultless, but for listening on the go with good acoustic isolation, it's assuredly one of the better choices. Especially since its shortcomings can be attenuated by making the right corrections. The very accessible price could well tip the balance in its favor.


The Good

  • easy to use
  • good extension in the highs
  • good bass with low extension

The Not So Good

  • slightly intense highs
  • Uncomfortable? These are the most comfortable headphones I ever used (among Koss, AKG, Beyer and other Senn models).
  • JT Kahle
    ive had a pair last 6 years, falling asleep with them on almost every night.