CES 2017 – Thoughts in the perspective of a professional audio practitioner

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CES 2017 has many up and rising technology trends this year, with a significant amount of attention invested in autonomous car technologies, mixed realities (augmented/virtual) and the Internet of things devices. These progressions made sense to me, as they are introductions to compliment our existing technological infrastructures to alleviate our already hectic lifestyles.

CES 2017, credit CES 

With a magnitude of new products and technologies launched within a few days, it is easy for one to feel lost or even not knowing what to get excited about. In this article, I will be sharing a few developments by manufacturers in consumer audio that interests me and what I feel may influence the general audio markets (professional / consumer). 

Audio Technica DSR9BT: Goodbye DAC!

There are numerous practices by audio manufacturers to improve their signal to noise ratio (SNR) in their products. From compacting an internal amplifier with high headroom to utilising better quality cables, Audio Technica has an intriguing approach to retain high SNR in their new Wireless Bluetooth Headphone.

"Truly" Digital Headphone, Audio Technical DSR9BT, credit Audio Technica

Conventional Signal Chain

The conventional signal chain of many existing headphones employs a digital to analog converter (DAC) early in the signal chain stage to amplify the audio signal to have the appropriate amplitude to drive the speaker components. Compressors and filters are commonly used to help improve signal integrity (e.g. signal gain compensation after transmission).

As previously mentioned in one of my articles (Investing in your audio system), any form of signal conversions, regardless of whether is it analog to digital (ADC) or digital to analog (DAC), these conversions will inherently produce unwanted noises (components tolerance) and decrease overall signal integrity. With a lower level of signal integrity, system fidelity will be affected.

The newly launched Audio Technica headphone has introduced a new technology that allows digital signals to transduce directly from speaker components. Conventionally, signals of analog nature are needed to operate the speaker components. However, Audio Technica’s Pure Digital Drive System allows the speakers to response to a digital signal without the necessity of any form of conversion beforehand. Do take note that the reproduction of sound at the end point is still analog.

How does Pure Digital Drive System improve SNR?

As compared to its analog counterpart, the digital signal has a discrete characteristic (1s and 0s), which in turn enable the signal to be robust against signal deterioration and also prevent signal distortions with lesser conversion stage along the signal chain. In my opinion, this is one of the most pragmatic approaches in the consumer market that have real potential to improve upon to help retain SNR and high system fidelity.

Upscaling any audio source into high resolution

It appears that there is a trend in CES 2017 where many consumer audio products are aimed to support high-resolution audio. Samsung has announced a new proprietary digital audio upscaling technology, Ultra-high Quality (UHQ) sound to “enhance” any audio format into a high-resolution format of 32 bits (bit depth). The sampling rate is yet to be confirmed, but speculation of 192KHz is expected.

Samsung h7 Wireless Speaker, credit Samsung

Will the upscale audio signal be true to its original format?

This can be an interesting development if Samsung has managed to development a upscaling protocol that is faithful to its original audio source. Existing upscaling technologies have always been biased towards pitch alteration. This is one of the digital artefacts created when a digital signal is over-sampled or under-sampled.

“Enhancing” Audio Quality

Audio Enhancement is not a simple processing of up-sampling the audio source. In musical terms, sound enhancement can be referred to as the improvement to the musical components concerning spectrum characteristics (e.g. clarity) or spatial imaging (e.g. “wideness” perspective of the audio source), etc. This additional information requires additional data, which is not innate in the source. Therefore, Samsung would have to develop a technology that is intelligent enough to study the musical characteristic of the song and melodically enhance various components to complement the overall experience.

LG SJ9 Soundbar Speaker: The first 4K speaker?

The LG SJ9 Soundbar Speaker System has incorporated a 320W system featuring two speakers that can either be used as a pair of front of house speakers (home setup) or delayed surround speakers. The soundbar has also incorporated the support for Dolby Atmos, an industry format that is commonly used in the film industry.

SJ9 Soundbar Speaker System, credit Gadget360

Who are they marketing to?

Looking at the features and design of this product, it is quite clear that LG is trying to target this product to movie lovers, home party enthusiast or even casual listener. The system can be configured up till a 5.1 setup to allow user to have a comprehensive immersion experience of listening to the system

A feature that raises eyebrows

The feature that gets discussed a lot in this particular product in CES 2017 is the 4K audio resolution format the system can support. This market term is derived mathematically from the bit rates of the stream audio signal. The system support 24 bits (bit depth) @ 96KHz (sampling rate), with a two-channel of audio, the stream would equate to 96000 (sampling rate) x 24 (bit depth) x 2 (two channels e.g. L-R) = 4,608,000bps≈ 4,000kbps, hence the term 4K resolution audio.

To give credit, this marketing term has worked its way through the sea of commotion in CES 2017. However, the format 24 bits @ 96KHz is not new at all. Most entry-level audio interfaces such as the Focusrite Scarlett 2i2 were supporting this format year ago with now having the support up till 192KHz. As discussed earlier, having high-resolution audio does not necessarily define the good quality sound, the acoustics of the environment will determine the second half of the overall experience. A more comprehensively designed system should include some form of acoustic alteration system through digital signal processing (DSP) where different profiles can accurately tune or control to benefit the most out of high-resolution audio.

On a more serious note

New LG Wallpaper TV, credit The Future Tech

Although the SJ9 was marketed inconjuncture with the new wallpaper TV from LG (4K resolution), the term 4K should not be used in audio as that constitute the amount of pixels generated per frame (pixel count). In contrast, audio signal does not involve any form of pixel generation (at least at this very moment), and manufacturers should uphold existing standards that have been rigorously tested for the use of the audio protocol. Marketing terminology such as 4K sound can bring welcomed attention to your product, and I support that. However, if these new terms are not elaborated on precisely should not be encouraged as it will cause many confusions, resulting in a more challenging environment for a casual consumer to purchase a product that truly suits his/her home setup.

YWFU

 

 

January Music Project: Fu Yong Hong - 我的心真的受伤了

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Recording with Zoom H5

In this month 's music project it will be a small experiment project with my brother on Christmas Eve 2016. The track is recorded with a Zoom H5 and XYH-5 attachment. The recording is done in one take with stereo X-Y configuration with the miking bias toward the vocal. Recorded track is then bounced into pro tools for post production. 

No distribution for profit. Credit when sharing.

Acoustical Isolation vs Acoustical Treatment – How to deal with entry points? (Part 4)

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Isolating the entry points of a room can be one of the trickiest parts when constructing an acoustically sensitive room. For this article, the following features door, window, ducking and outlet bays will be referred as entry points. As these entry points require some level of manoeuvrability (e.g. opening of doors), the design of these features demand it to be acoustically sealed when it's put in place. If the features are not done properly, they will be the weakest link of the room acoustically as air provides almost zero transmission loss (TL) (Part 3).

The importance of a door

Essentially, a room cannot function without a door. While most of the features mentioned above are designed to be permanently sealed, doors are designed to be open. This presents a challenge where the doors need to maintain at least the same level of transmission loss to the wall attached to it. Thus, a door design, in this case, would require sufficient mass (part 3) and also a closure system that reliably seals the entire perimeter around the door. Some doors are specially engineered for this very purpose, and it will provide excellent results in this application. However, if you are on a budget, here are some pointers for you to look out for some alternatives with the appropriate mindset.

In general, a hollow door can only provide an STC rating of around 20s and of course a door with a solid inner core (more mass) will have a higher rating (around STC-25, higher but still ineffective). In contrast, metal door performs better than wood doors, but that poses another challenge for reflection (covered in later parts of the blog series). Similar combinations between interior airspace stuffed with absorbent material and partition board can be employed for the fabrication of the door (part 3). As for isolation when the door is closed, we need to ensure that the door is gasketed and airtight. To seal the gap between the door and frame, several materials have been used to provide pleasing results, namely, rubber strips or neoprene foams. In some cases, magnets have been used to DIY between the frame and door to help improve the compression of the door to the insulating materials.

Neoprene tubing, possible material to stick between frames, credits 1001blocks

Windows are important too! 

If you have the luxury to have separate rooms for your recording needs, then a window might be essential. Although in today’s technology standard, it might be cheaper to install a set of camera and screen in both rooms as it can provide higher insulation when done properly, it does not compensate for the human interaction component for artistes to help them calm their nerves down. A window can contribute to making space feels and looks less claustrophobic; it also provides the visual stimulant for the artiste and engineer to communicate. In some cases where an artiste does not wish to be looked when recording, curtains can be hooked up to provide the privacy he or she needed.

Despite that, most of the suggestion I’ve mentioned so far require construction works, and I will not be surprised that some of you have superb craftsmanship to do it yourself. However, building an acoustically sound window is challenging (in my opinion) but here are a few recommendations to help you look out for or build (seriously? If you do please share it with me!) a window. Firstly, plastic can be used in the construction of a window, although it does not provide as much transmission loss rating as glass does. The principle difference is that plastic would require double the thickness to provide the same amount of transmission loss on glass. Hence, the glass may be a better material to start on. Secondly, which is better single-pane or double-pane window?

Single-pane window vs. Double-pane window

The single-pane window is commonly used in household and does not provide good sound insulation. Thus, you might have observed that if you are living near a bus interchange, your flat will probably come with a double-pane window to help insulation the outside noises. The ideology follows similarly to the construction of a wall (part 3), a logical thought process would conclude that more panes (higher density) will offer greater loss. Beside mass law, it is shown that a double-pane window separated by an air gap can provide approximately 30dB of transmission loss. As the window provides a visual cue to both parties on either side of the room, it will not be advisable for you to stuff absorbent materials such as fibre glass to help improve the insulation. Hence, it would be even more important for you to find a good ratio between the partitions thickness (e.g. glass) and the interior airspace. For a simple guideline, a double-pane window with an interior airspace of 0.1m sandwiched between a 0.01m and 0.006m glass panels (total thickness of 0.116m) can provide an STC rating of 42.

Cross-section of a double-pane window, credits Glassdoctor

What about introducing a third pane? 

If you’re wondering whether does introducing the third pane further improve the STC rating, the short answer is yes but not significant. Through extensive research in 1983 from Quirt, J. D. measuring the difference made between windows (double glazing and triple glazing), the result in the differences are subtle. Although some might argue that a triple-pane window does still increase the insulation, I feel this is a diminished effect, and you can spend it better in other areas. Otherwise, do indulge yourself with it if you can afford.

In the next article, we will look further into treating other entry points such as heating, ventilating and cooling system.