Sennheiser CX 6.00BT Review (Page 3 of 4)

Page 3 - Subjective Audio Analysis

I get it, my $1000 phone does not have a headphone jack.

Reviewing audio devices require extensively trained ears and lots of experience. Even for audiophiles, it may prove challenging at times to obtain an accurate evaluation of a product without a thoroughly familiar product to use as a simultaneous reference. While I am not going to even try to claim that I am the only trustworthy or best reviewer for sound, it is fact that most computer review sites have editors who are insufficiently trained in reviewing audio equipment. Give them practically anything and all you will read about goes along the line of "good bass, nice midrange, awesome treble, really clear sound, 10/10". While there are many knowledgeable audio reviewers at various respected online media outlets, they are by far the minority.

As I have mentioned in my past audio reviews, there are really no true objective measurements for speaker sound quality. As the reviewer, however, I will put it through a series of subjective tests to try to come up with the most objective rating possible (Yes, it is quite a paradox haha). For portable tests, including wirelessly via Bluetooth, I used an Apple iPhone X. This is a state-of-the-art device at press time that requires no introduction, and will reduce its potential to be a limiting factor in our auditioning.

After over 30 hours of break-in time -- well above typically required period -- we put the Sennheiser CX 6.00BT to the tests. All tracks were AAC or LAME encoded MP3s at 192kbps or higher.

Once you put on the Sennheiser CX 6.00BT and listen to your first song, you will notice its distinct V-shaped sound character. However, its punchy sound signature does not necessarily imply it will corner the market for people looking for something fun and makes them feel like they are in the club. Let me explain why.

Starting with the bass, I found it to have many characteristics of good bass -- deep, solid, round, smooth, defined, and articulate. The punchy nature of the V-shaped distribution meant the low frequencies were slightly boosted; while being reasonably controlled to be powerful without overwhelming. However, this also implied the midrange was slightly recessed compared to the bass and treble. It was clear, but it was of only average thickness and range. There was nothing particular to note in terms of saturation, warmth, and richness in my opinion. Its midrange was just run-of-the-mill; I personally prefer something more saturated, warm, and rich.

As we move up the frequency scale, the boosted treble finished off its V-shaped frequency distribution. You will immediately notice the forward sounding treble the moment you put on the Sennheiser CX 6.00BT earphones. On the good side of things, the treble was sharp, immediate, tight, clear, and crisp mainly in the areas of the high hats of a drum set. However, the treble was of only moderate brightness and energy. It was much more energetic than the Focal Spark Wireless, but I found the Spark to be more comfortable to listen to. What I did not like about the CX 6.00BT was the overall dry and clashy upper frequency response; often sounding tinny and thin. Because of how forward the treble was, the flaws of the upper range became a dominant drawback in the listening experience of these Sennheiser wireless earphones.

In terms of imaging, I would classify the CX 6.00BT to be neutral. However, the soundstaging was not defined with its narrow width and depth. It was narrower than the Focal Spark Wireless, which did not have a wide soundstage, either.

When playing through my favorite benchmarking tracks, the Sennheiser CX 6.00BT delivered good detail, precision, and resolution. The frequency separation was also commendable. However, as aforementioned, the treble could be cleaned up. It also sounded a bit rough between layers, and as a whole, lacked a strong cohesive bond. As a result, the songs I played did not sound like a solid, defined piece. I found this strange, since if you listen for each auxiliary technical element like layering and frequency separation, the CX 6.00BT scored acceptably. However, when you step back and look at the big picture, it simply did not feel cohesive. Simply put, these earphones did not have remotely comparable layering smoothness, depth, and definition when placed next to star earphones like the V-MODA Zn. I understand these two products are of completely different market categories -- the Zn costs 80% more and is not wireless -- but the fact they are not even remotely comparable is quite telling. The Focal Spark Wireless retains the upper hand in these categories as well, which carries an identical MSRP at press time.

The Sennheiser CX 6.00BT is a closed IEM, and comes with four different sized sleeves for maximum compatibility. The earphones had a good fit in my ears, provided great seal for excellent environmental sound isolation. The microphone also worked very well for calls on the go.

The Sennheiser CX 6.00BT suffered from a problem common to all products in this category: Background hissing noise when turned on. You probably will not be able to hear it when you are on the train or the bus, but you will be able to pick it up it in quieter locations. In terms of lag, I did not notice any significant delay; audio appeared to be properly synchronized to videos I was watching on my iPhone. The CX 6.00BT are aptX LL certified earbuds.

The CX 6.00BT's rated wireless range is unspecified, but from my tests, you should never exceed its maximum range under normal operating conditions. I could walk even a couple floors away in my house and still maintain a reasonably consistent connection. This shows a well-designed antenna, and I noticed no connection inconsistencies with my Apple iPhone X.

The company estimates the battery to last around 6 hours on a single charge. At around 35% volume, which is a comfortable listening volume, the CX 6.00BT lasted 7 hours and 17 minutes according to my tests. Note I did not press any buttons on the remote in the process, which may reduce the battery life. One annoying thing about the CX 6.00BT was its inaccurate battery reporting. For example, 6:45 into the test, the earphones were still reporting 40% remaining. However, it was completely dead a little over half an hour later.

Overall, the Sennheiser CX 6.00BT are good earphones if you like V-shaped frequency distributions, but the slightly recessed midrange in conjunction with the tinny and dry treble may increase listening fatigue over extended listening periods. The Sennheiser CX 6.00BT can be improved by cleaning up the treble, smoothing out the entire range, and increasing its cohesiveness for a more solid and powerful output. Doing so will greatly increase the appeal of these earphones.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Subjective Audio Analysis
4. Conclusion