Sony SBH80 Part.2: The next-generation wireless audio

Continued from Part.1, Aesthetics

As a part of Sony's New Smartwear Experience Vision project, Sony SBH80's main goal is to be fully integrated in the user's lifestyle through seamless wireless connectivity. Featuring Bluetooth 3.0 standard, Advanced Audio Distribution Profile (A2DP) v1.2, and apt-X compression algorithm, SBH80 is claimed to be the next-generation wireless audio device.

And of course, as a headphone reviewer, I can care less about their marketing schemes and focus solely on the sound quality of the headset itself. Indirectly, I've dealt with quite a few Bluetooth-enabled headsets while working as a technical advisor at seeko.co.kr. Surprisingly, every single one of them has failed to impress me. Whether the problem is sourced from a poorly designed unit, or from the wireless interface itself, Bluetooth headsets have always exhibited either a completely skewed frequency response / time domain characteristic due to latency, or a short frequency response bandwidth; I've never seen a headset that can be considered as "Hi-Fidelity".

... Or maybe not just yet?

PRO: Excellent channel-matching, wide frequency bandwidth extended well up to 20 kHz. Although there's a good amount of second-order harmonic distortion present at 1.4 kHz, it shall be perceived as 'musical' since the distortion is of an even order. Moreover, apt-X helps enhance the overall sound quality greatly. While strong emphasis in the low frequency range is a little letdown for me personally, others may find it quite entertaining. And due to the driver's resonance-free characteristics(smooth frequency response), SBH80 will behave more intuitively to custom equalization than most of its competitors.

CON: There's a slight diaphragm flex noise when the IEM is inserted into the ear canal; this may be remedied by porting a tiny venting hole on the ear sleeve with a needle.

ON SECOND THOUGHT #1: As far as insertion depth goes, SBH80 is invulnerable. Here's the comment of the audio designer, Mr. Smailagic, regarding the insertion depth of SBH80:

"During typical shallow insertion depth ... with SBH80, these areas(8-9k and 15-16k) will be relatively smooth ... sharp resonances (especially those in the lower treble range 5k-9k) contribute to frequency masking, so removing these will increase overall fidelity, and as a result, you’ll get smooth and natural treble response."

Thus, regardless of what the practical insertion depth is, users should be able to enjoy the sound quality of the headset in full.

ON SECOND THOUGHT #2: Since the headset is such a fine-tuned product, modifying its acoustic filter design is not recommended, unless the modder really understands what s/he is trying to accomplish.

ON SECOND THOUGHT #3: Although stock sleeves yield the smoothest frequency response, some third-party sleeves, such as Phonak or UE biflanges should exhibit an equivalent result as well.

ON SECOND THOUGHT #4:  According to Sead Smailagic of Sony Mobile, Sony SBH80 shares many technical similarities with its predecessor, MH1.

"...in SBH80 I tried to pronounce mids related to upper bass area in order to further increase clarity and make it more linear DF(diffuse-field) wise, further F0(resonant frequency) is slightly shifted down and is expected to be in range of 2.8-3kHz, compared to MH1 ~closer to 3.5k."

And consequently, his statement can be verified by examining the above graph. While maintaining the bigger picture largely intact, SBH80 is tuned to have less mid-bass, downward-shifted ear canal resonance(simulated), and less harsh (quarter wavelength) resonances in the upper treble around at 10 kHz.

"... all these ... have actually contributed to an overall heavier loudness curve compared to ... MH1 ... one another motivation behind the bass boost is also adaptation to various environments in combination with recommended lower SPL listening levels."

The end result is a negative-sloped diffuse-field oriented tonal signature with a bit of attenuation around at 6 kHz ~ 10 kHz range to accurately accommodate his reference target. In addition, in order to achieve an ideal tonal balance while listening at a safe sound pressure level, and to negate microphonics/environmental noise derived from portable usage, the equal-loudness contour has been compensated as well in the low frequency range. Still, while many would find such sound fun & easy to listen to, some, like myself, may find this little too bass oriented.

"... one thing that can be said is that these subjective preferences differ quite heavily between different groups. So, those parameters that are common for all those groups should've been seen as basic design approach, while the final tuning should be adapted according to the target group ..."

However, as such tuning has been turned out to be more preferred by the majority of users subjectively through numerous research and tests done by Sony, it is inarguable that the decision has been "correctly made" for a consumer product. Since the headset is a product of the engineer's intellectual decisions, I shall honor his idea and philosophy.

ON SECOND THOUGHT #5: On a side note, SBH80 matches the reference target announced by Dr. Sean Olive of Harman International fairly well. Personally, I prefer de-emphasizing the 70 Hz region about 3 ~ 4.5 dB.

CONCLUSION: I've never been a fan of wireless audio in my life. Back in 2004, I purchased a wireless headphone made by Sennheiser at a local audio shop called Good Guys. The sound quality was extremely horrible, not to mention a gross static noise that always lingered in the background. I absolutely hated the quality, and never looked back at the wireless technology since then.

And 10 years later, in conjunction with the latest innovations, Sony finally brings a wearable device that fulfills the standard of the most demanding customers, such as Hi-Fidelity audiophiles. For me, this is a ground breaking moment, which shatters my 10-years-long preconception. From enhanced sound quality to a long lasting battery, there have been so much improvement with the technology, which can truly be described as "Hi-Fidelity".

As a final remark, here's a comment from the audio designer that sums up the humble, yet noble value of this product:

"... with SBH80, I really hope we can get some attention from the audiophiles and show that this product has taken a serious step towards Hi-Fi quality in the wireless headphone market." - Sead Smailagic

For more information, please visit:
http://www.sonymobile.com/global-en/products/accessories/stereo-bluetooth-headset-sbh80/