Bluetooth 5.0 and Others: Demystifying aptX HD, Low Latency Standards and MIDI Technology

Bluetooth 5.0 and Others: Demystifying aptX HD, Low Latency Standards and MIDI Technology

We have written about the Bluetooth technology in detail, especially about the audio applications, common information, and profiles of HFP, HSP and A2DP, and the aptX HD, which audiophiles love. Several projects classified as high-profile in the domain of consumer electronics during this period in time, glittering marketing and advertisements, have fallen unconscious. On the contrary, Bluetooth is here to stay! Let us see what latest achievements this technology, which is already being developed since 1993, has seen in modern times.

Bluetooth, which is already replacing cables, has been much more convenient and loyal to the users. The updates are also being provided at an appreciable regularity. In previous years, Bluetooth 4.2 appeared on the market and had differences, i.e., increased data transfer speed and privacy when compared to Bluetooth 4.1, which was widely used at the end of 2013. Bluetooth 5.0 is now being enjoyed by the world. This technology has an increased range, and the rate at which data is transferred has also increased significantly. Moreover, this technology comes with better noise immunity than the previous versions. All this has adequately updated the technology of audio transmission.

It is predicted that by the next year, there would be 14 billion devices in use that have this technology. One reason which can be attributed to the widespread popularity of Bluetooth is its backward compatibility. This means that if your smartphone supports Bluetooth 5.0, while the version of Bluetooth technology on your headphones is 4.2, and they interact with each other, there would be no problems in connecting and usage.

Airpods 2.0 - Benefits of Bluetooth 5.0
Airpods 2.0 - Benefits of Bluetooth 5.0 | Source: Unsplash

1. Benefits of Bluetooth 5.0 Technology

Let’s start off by looking at the development in the specification of Bluetooth Low Energy in Bluetooth 5.0, which is finally being used by the audio devices. This implies that your digital devices, including smartphones and headphones, can work for a longer time on a single charge of battery while being connected with Bluetooth. Another feature in Bluetooth 5,0, which distinguishes is the Dual Audio function, which enables it to play music simultaneously on two connected devices. For example, listening to the same music track with your loved one is quite romantic.

Bluetooth 5.0 has documented the ability to work up to a distance of 240 meters. The public is making use of these features as they are made available. The developers of this technology call the documented function as a great achievement, which has been made possible “after years of research and repeated tests”, which surely is remarkable.

1.1 High Data Transfer Rates - Bluetooth 5.0

The most beneficial feature of Bluetooth 5.0 technology is its ability to work with data transfer rates, which are as high as 2 Mbps. This data transfer rate is actually double the rate that Bluetooth 4.2 supported. What real achievements been achieved from this? The answer is quite simple; the ability to experience uncompressed Hi-Res files sounds! To put this into the right perspective, at the 1 Mbps speed, which came with Bluetooth 4.2, the implementation of the aptX compression standard was already achieved. This ensured that the quality of the digital audio that was transferred is as good as on a CD, With Bluetooth 5.0, the transmission rate is capable of bringing you much better quality than that.

2. AptX Family: Adaptive, Low Latency, and aptX HD

From this point onwards, fanfares and timpani (having a natural HD quality) – Qualcomm aptX HD appears on the scene. It is designed keeping in mind the ever-growing demand for music lovers to experience Hi-Res audio. 24-bit Bluetooth music quality having frequencies as high as 48 kHz are supported by this advanced codec. The signal-to-noise ratio is another great achievement and reaches up to 129 dB. This value is unique in the sense that it cannot be found on any modern DAC of the reference level.

Independent tests were conducted by the Salford University, and a quote of the results can be found on the site of the developers which states that after analysis of the results from the test of 24 people who cleared the test, it can be concluded that the test’s participants were not able to consistently detect the difference between 24-bit / 96 kHz sound 24-bit / 48 encoded and decoded sound kHz aptX HD.

Now let’s have a look and do an analysis on aptX HD implementation on the Qualcomm SOC CSR8675 audio chipset as an example. It can process end-to-end 24-bit audio, and in comparison to its predecessors, it can process deeper digital signals. Due to the sequential coding and decoding during the process of transmission/reception, the reduction in the signal-to-noise ratio is also achieved. This technology also claims a reduction in distortion, especially from the 10-20 kHz range.

A programmable 80-MHz RISX processor is being run on the chipset. The processing of the audio signals is done by the 24-bit Kalimba DSP processor which is integrated. A 24-bit ADC stereo is also on board and has a frequency of range up to 96 kHz. A 24-bit DAC stereo, which is also built-in, works to implement sampling frequencies of up to 192 kHz, while the margin is set for the parameters.

2.1 Qualcomm aptX Adaptive Audio Codec

The Qualcomm chipset technology developers did not stop there and also offered the aptX Adaptive Audio Codec. It has a lesser delay in the dynamic mode, which is considered to be perfect for the headsets used during gaming. It also provides an adjustable bitrate, which can be adjusted to the rate of data transfer to ensure seamless communication. When it was released, Qualcomm referred to aptX Adaptive Audio as a tuned audio codec, which is dynamic in nature and has backward compatibility with the aptX and aptX HD.

According to the claims of the company, the codec is designed in such a way that it automatically tunes for enduring optimal quality of sound. The aptX Adaptive is able to run on two bitrates, i.e., 276 and 420 Kbps. In the second version, based on algorithms based on some advanced coding, it even leaves behind the aptX HD concerning certain parameters, including signal to noise, but not by much.

2.2 Qualcomm aptX Low Latecny

One other Qualcomm codec is the aptX Low Latency, which utilizes the Bluetooth 5.0 technology for audios of low latency. The end-to-end delay is provided by this technology when the transmission is being done via Bluetooth, not higher than 32 ms. The delays in the normal stereo Bluetooth can vary greatly and are dependent on the implementation and buffering of the system. Still, normally it has a higher magnitude, and it is noticeable. More specifically, the usage of Bluetooth devices for connecting wireless headphones with the TV was nearly impossible. As a matter of fact, +40 ms to -60 ms is the recommended delay in synchronization of audio and video in broadcast television. For concerts and the studio monitor systems, the most feasible and technical solution should be within the 20-30 ms level. The Low Latency aptX is almost approaching that and providing the latest features, especially for the gaming community. We no longer can experience the delay 32 ms had.

3. Video & Midi

More than ever, the capabilities and features of Bluetooth 5.0 have become the possessed belongings of the genuine lovers of high-quality music. But this does not imply that advancements in Bluetooth technology have not entered into the other domains of multimedia entertainment.

On the site of the Bluetooth SIG organization, which is involved in the development of technology, you can find a section that has the existing specifications. You can also find the A / V remote control profile – AVRP, HID, the standard GAVDP audio/video profile (which is in existence since 2012), the user interface device profile, the extended A2DP audio distribution profile version 1.3.2 and many other promising features.

Attention should also be paid to the Bluetooth MIDI technology, which is also widely known as Bluetooth SMART and is distributed amongst the MIDI community. Here we are referring to playing MIDI records through MIDI sequences generated by the interfaces such as plant growth, or via Bluetooth. These Bluetooth technologies have provided freedom for new experiences and given the margin for creativity. What we can expect the Bluetooth technology to provide us in the near future with its development will become evident soon with time. The new version is expected to be released shortly.


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