The Wireless Speaker and Audio Association (WiSA) was established in 2011 to promote high performance wireless audio to the home theater market. As HDTVs continue to slim down, the first victim is often audio. While external sound bars satisfy some consumers, others believe there is still a need for a high quality audio alternative. RS recently spoke with WiSA’s president Jim Venable to find out what the organization anticipates will evolve in the channel over the next few years.
What changes has wireless audio undergone in the last few years? What do you think have been the greatest influences on these changes?
One of the changes that has occurred is that HDTVs are getting thinner and eventually all the electronics will be external to the display. The first to go is the audio, since there is very little room for quality speakers. However, HDTV manufacturers know they need to provide an audio alternative. Additionally, since cost is a huge issue for them, some manufacturers will offer external sound bars, which will satisfy some consumers, but there is a need for a high quality audio alternative, too. The market is at an inflection point and manufacturers knew that in order to develop a long-term product strategy and give consumers what they want; they needed to come together and develop a standard similar to the Wi-Fi association model.
One of the biggest changes in the residential space is simply the number of devices that are operating in the 2.4GHz range. It started with the microwave oven, then digital wireless telephones and baby monitors. Then came the introduction of 802.11b computer networks, which opened up wireless networking and Internet access. Since this band has plenty of bandwidth when there are few users, 2.4GHz usage spread to security cameras, 802.11a, 802.11g, 802.11n, baby monitors, myriad Bluetooth applications, and even ‘smart’ power meters. It is estimated that the demand in the 2.4GHz band will triple by the year 2016, causing a great deal of congestion in that frequency band.
802.11a (and later, 802.11n) also operate in the 5GHz U-NII (Unlicensed National Information Infrastructure) band, with a few channels around 5.2 and other channels around 5.8GHz. There were hopes that this band would provide some relief to 2.4GHz congestion however, it was hampered by its inability to go very far through walls.
In 2007, various international authorities granted unlicensed use to up to 15 additional 20MHz frequencies between 5.2 and 5.8GHz, making the total number of channels available in the 5GHz band up to 24 (2.4GHz has only 4). The restriction in this frequency range is that the radio must monitor and avoid military and weather radar by changing frequencies when those are detected (this process is referred to as Dynamic Frequency Selection, or DFS).
5GHz communications never caught on because of the need for dual-band (2.4 and 5GHz) radios, and because it doesn’t penetrate solid objects very well. Furthermore, DFS has a detrimental impact on network throughput due to the complexities of monitoring and picking a new channel.
For this very reason, the WiSA Association-supported technology uses the 5GHz, and preferentially the DFS, band to avoid radio congestion. Because of the very nature of audio communications, the process of DFS monitoring and channel selection can be designed into the communication architecture such that a new interference free channel is always available and eliminating information loss when switching channels. Once radar monitoring has been implemented, it is natural to avoid any other radio signal and simply pick one of the other 24 channels. Home theater applications do not require long range or extreme object penetration, so the signal will be solid.
What specifications are significant to the continued growth of wireless audio in residential integration? How is WISA going about developing these specifications and standards?
The WiSA Association was founded to advance the adoption of wirelessly transmitted high-definition (HD) surround-sound audio in the home theater environment by establishing the industry’s first interoperability specification and compliance testing programs for manufacturers of high-performance wireless speakers, DTVs, Blu-ray Disc players, and other consumer electronics (CE) devices.
The WiSA Association strives for great quality audio with low latency as a replacement for speaker wire. In a home theater, the signal is split into video that goes to the display and audio that goes to the speakers. If there are many frames (or even several seconds) of latency in the wireless audio transmission, there could be lip-synch issues. Some audio transmission schemes actually increase and decrease latency depending on network conditions, which causes lip-synch issues which make compensation impossible. Low, fixed latency is really key in home theaters so that lip-synch can be maintained. This is achieved by avoiding communication problems by picking a broad spectrum and avoiding conflicts. All of the bandwidth is available—all the time.
The relationship between WiSA solutions and others is hand-and-glove. Other streaming networked content is received by the display or the AV receiver and then sent to the speakers wirelessly. The audio to the speakers has no encoding or compression so that every presentation gets the highest quality audio possible.
Where will wireless audio be in the next five years? What developments do you anticipate will revolutionize wireless audio and take it to the next level?
The new development we foresee taking hold over the next five years are the requirement for higher bandwidth, meaning more channels (> 8) and/or higher quality (192kHz/24 bit) and the introduction of using batteries for surround, rear speakers or outdoor speakers which require less energy than front speakers.
Ultimately, consumers want HD wireless surround speakers to match the HD video quality of their HDTVs, Blu-ray players, music and gaming consoles; however, until now they had limited options to support this desire. The WiSA Association provides a solution to this problem by offering interference-free HD wireless audio, ease of set up, as well as interoperability with other CE devices with the delivery of its compliance test specification and certification and logo program. This is revolutionary in that consumers will have greater flexibility to mix and match component and speaker brands that are WiSA compliant, as well as the convenience of being able to reconfigure their living room by easily moving speakers around.
—Llanor Alleyne
