The Emerging Home Audio Ecosystem Places New Demands on Wireless Audio Technologies
A wireless home audio solution needs to support a wide range of devices with no loss in audio quality while providing a great listening experience for consumers. All of this needs to be done without breaking the bank. It can be done in the 2.4 GHz spectrum and all starts with the radio.
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By Ralph Mason, Kleer
The modern home is filled with an increasing variety of high quality audio sources including CD players, home stereo/theater systems, personal computers, TV’s, portable media players and music phones. There are also a variety of audio receivers such as speakers, docking stations, headphones and earbuds. Currently, the majority of these systems are wired which severely limits the ability of these devices to operate with each other and also creates a nightmare in terms of tangled and unsightly wiring. As a result, consumers are looking for wireless versions of these products that can communicate throughout the home from any audio source to any audio receiver without sacrificing audio quality or requiring a costly upgrade of components.
Creating products that can meet these demanding requirements requires a systematic approach to the radio technology that takes into account not only the important technical specifications such as; power consumption, audio latency and wireless coexistence but also the more consumer-focused needs such as; guaranteed interoperability between different product manufacturers, simple and intuitive pairing between multiple devices, remote device control and transport and display of music file meta-data such as song title and album art. In fact, meeting these requirements requires the creation of a flexible audio ecosystem that can easily be configured to the consumer’s needs without any special technical skills and with minimum additional costs.
Wireless Home Audio Interoperability Creates a Wide Range of Demanding Radio Performance Requirements
Given the obvious advantages of wireless home audio it would seem surprising that it hasn’t become a mainstream technology already. Unlike wireless data or voice network, wireless audio networks require a very high quality of service as the loss of even a single audio bit can be detected by human hearing. If that wasn’t hard enough already, the wireless audio network must be able to cope with a multitude of interference sources and coexist with (i.e. not interfere with) a host of other wireless technologies—a challenge exacerbated by the proliferation of Bluetooth and WiFi radios in the home. A number of technologies have tried to address these stringent requirements by creating large audio buffers that can continue to stream audio when there is interference on the wireless network. Unfortunately, this is not acceptable for home audio where the time delay (commonly referred to as latency) introduced by these buffers causes lip-sync problems when viewing video and echo and reverb when listening to a multi-channel home theatre system. Bluetooth is especially prone to this problem.
The consumer also wants to be able to listen anywhere in the house or even on the patio, so good range and the ability to simultaneously support multiple speakers/headphones is important. One other thing, consumers hate recharging batteries so ultra lower power consumption is required for any battery powered components like your iPod or wireless headphones. Oh, and don’t forget, most people don’t like paying a lot for their wireless upgrades so low cost is critical as well.
So, low latency, nimble coexistence with Bluetooth and WiFi, long distance, as well as low power and cost place incredible demands on the underlying radio technology.
Audio Where You Want It, When You Want It, No Fuss
Getting quality audio data from the source to the receivers is only part of the solution. In a home audio ecosystem that has many sources and receivers some type of wireless control channel is also required that allows consumers to easily select which sources connect to which receivers. The control channel needs to support everything from simple button controls, such as those found on a headphone, to a sophisticated GUI like you might find on a custom iPhone application. The control channel should support both local control, (i.e. at the source or receiver) and/or centralized control with a dedicated remote control device. In addition to controlling connectivity, the control channel needs to support audio playback controls such as song selection, play/pause and volume up/down while transferring music file meta-data such as song titles and album art which allow a user to get remote information about the music that is currently playing or that they might wish to play next.
It Can Be Done in the 2.4 GHz Spectrum
All of these sometimes conflicting demands would seem to imply that it is next to impossible to provide high-quality wireless home audio in the 2.4 GHz spectrum. In truth, unless the underlying radio technology is designed with all of these requirements clearly in mind, the task is daunting. Bluetooth and WiFi are examples of technologies designed for other purposes that fall short in the wireless home audio environment. There is a role for a “third” 2.4 GHz radio that enables truly interoperable wireless home audio systems by paying careful and diligent attention to all aspects of the system all the way from the smallest radio packet format to the highest level GUI control commands.
Ralph is a founder of Kleer. Ralph is a recognized leader in the area of analog/mixed signal circuit design, and has been actively involved in integrated circuit (IC) related research and development for over 17 years. Prior to co-founding Kleer, he was the product line manager and senior analog IC design engineer with Philsar Electronics.
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2012
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