Page 3 - Subjective Audio Analysis
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). Tests were conducted primarily wirelessly via Bluetooth. I mainly used a Sony Xperia X and an Apple iPhone X. For any analog tests, we connected it to the Sony Xperia X only, since the iPhone X has no headphone jack. Some analog tests were conducted with the Auzentech X-Fi HomeTheater HD sound card as well (Creative CA20K2 DSP/APU, National Semiconductor LME49720NA OpAmp, JRC NJM4580 signal buffers, Cirrus Logic CS4382A DAC, Nichon MUSE ES capacitors). These are some of the best consumer sound equipment out there in the market today, and will reduce its potential to be a limiting factor in our auditioning. After over 80 hours of break-in time -- well above typically required period -- we put the Sennheiser HD 4.50 BTNC to the tests. All tracks were uncompressed CDs, FLAC, or LAME encoded MP3s at 192kbps or higher.
While I normally would start with the three regions of frequency, the first thing to really pop out at me was actually the active noise cancellation or ANC. I have used other headphones with ANC before, but this was definitely a positive experience. External sounds definitely were removed and the difference was drastic. Even when Editor-in-Chief Jonathan Kwan plopped these headphones on, he immediately knew something was different. This makes the headphones great for on-the-go listening. One thing I should note is the fact enabling and disabling this feature does play a role into how the headphones reproduce audio, so I will mention it throughout this analysis. All of our tests were ran with ANC both enabled and disabled to get a clearer picture of the capabilities of the Sennheiser HD 4.50 BTNC.
Moving to the low end, the Sennheiser HD 4.50 BTNC produced some really nice bass. Not only was the amount sufficient, but it was smooth and full without feeling hollow. It is pretty obvious there is quite a bit of bass and maybe even too much for some listeners. It does come down to preference, but I will say the quality of the bass was great nonetheless. I compared this with the V-MODA Crossfade II Wireless, and I have to say the bass between the two were quite comparable, though the Crossfade II Wireless feature a heavier low end. With the active noise cancellation disabled, however, we lost quite a bit of the bass, and the difference was pretty apparent. Even so, the oomph and quality of the bass was quite good.
When it came to the middle frequencies, I found the Sennheiser HD 4.50 BTNC provided some good qualities here. Vocals and instruments in this range sounded natural and wet. Compared to the Crossfade II Wireless, which features a more forward midrange, the HD 4.50 BTNC's midrange was more recessed, though it is not a bad thing. The low-mids were also more recessed compared to the lower and higher end. Even still, the Sennheisers produced an audibly pleasing sound.
Finally at the peak, we had a decent treble response from the Sennheiser HD 4.50 BTNC. As we moved from the lower trebles and upward, there were some dips in the treble amplitude, though it was not as noticeable. Vocals and instruments like violins were produced with clarity and without dryness. I think the higher vocals, which can be classified as high middle range to low trebles, were a bit more amplified here too, resulting in a brighter sound. Thankfully, everything is pretty clean overall. When it comes to the balance of the three, we noticed a dip in the middle range, which resulted in a slight V-shaped sound profile. This may not be reference flat response some may be looking for, but this does result in an audibly pleasing sound for the general public with greater emphasis in the bass and treble.
While active noise cancellation plays a pretty big role in areas like sound isolation, they do have their negatives too. Soundstaging is one area that suffered as a result of this feature. As the entire role of ANC is to create a more isolated environment, the soundstage is not going to be as open. Indeed, the sound produced from the closed-back, 32mm drivers in the Sennheiser HD 4.50 BTNC was as expected in terms of staging. While they are not the worst we have heard, the HD 4.50 BTNC produced a narrower sound, creating the perception of sound being more in the head rather than in front of the listener. To be clear, while it would have been nice to see a wide sound produced, this is not too surprising. With ANC disabled, the soundstage was slightly wider, though it still was not as deep as I have heard before. Otherwise, the image produced through the Sennheiser HD 4.50 BTNC was relatively neutral.
When it came to layering, the Sennheiser HD 4.50 BTNC did a pretty good job in handling the multiple intricacies of the different regions. Despite testing the HD 4.50 BTNC in complicated and messy audio circumstances, it was more than capable in handling and reproducing the sounds without dropping details. Even with the relatively recessed midrange and heavier bass, we did not lose too much. Detail and resolution was good overall. As for frequency separation, I felt like the three regions were distinct and clear. However, there were also smooth transitions between the frequencies without any apparent frequency banding. The output from the Sennheiser HD 4.50 BTNC was also quite clean.
As for the differences between wired and wireless operation, the Sennheiser HD 4.50 BTNC exhibited a lot of similar issues we have seen in other Bluetooth products. For one, you could hear a slight hissing noise when operating the headset wirelessly. Even though it was quite faint, it was still noticeable in quieter environments. In addition, there was a bit of lag noticed, and while it is not a huge thing, you will probably tell when watching a video on your device.
When I saw the original estimates of 25 hours of playback and 19 hours when the active noise cancellation is enabled, I was a bit skeptical. During my tests, these claims proved to be true, as I was able to easily listen for hours on end without needing to refuel. The Sennheiser HD 4.50 BTNC also charged relatively quickly. As for the range, the ten meters estimate was pretty much correct. I did not experience any wireless inconsistency issues while paired with my daily driver, the Sony Xperia X.
Overall, the Sennheiser HD 4.50 BTNC packs a punch with its features and combines it with a very respectable sound performance. With its active noise cancellation and favorable audio qualities in many areas, it really has the right features for a traveling pair of headphones. It may not necessarily be a great reference headset and could be improved in the soundstaging areas, but I have to say you are still getting a very good sounding pair of cans in the HD 4.50 BTNC.
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Subjective Audio Analysis