I've been following WiSA (the Wireless Speaker and Audio Association) since its inception in 2011. This industry group has developed a robust, open standard for transmitting up to eight channels of high-resolution (24/96) uncompressed audio wirelessly in the 5 GHz RF (radio frequency) band. In fact, it uses the 15 channels of the UNII (Unlicensed National Information Infrastructure) band, which are not used by WiFi, thus providing sufficient guaranteed bandwidth to support eight channels of 24/96 audio. These channels are used by military and weather radar, so they must be monitored carefully and relinquished if needed by those applications, but if the system detects any such activity, it instantly moves to another channel, allowing uninterrupted transmission.
At CEDIA, WiSA reps were monitoring the traffic in the 2.4 and 5 GHz bands, claiming that none of the 2.4 GHz WiFi-based whole-home audio systems on the show floor—which is most of them—were working because of all the activity in that band. (I was not able to verify that for myself.) They even provided me with screen shots of the traffic:
The 2.4 GHz WiFi band was very congested in the WiSA sound room and, presumably, throughout the show floor, as you would expect at a tech conference.
The 5.0 GHz band was much less crowded; the five peaks seen here are all WiSA streams.
Virtually all the currently available whole-home wireless-audio systems are designed for multi-room, 2-channel distributed audio, whereas WiSA is designed for single-room, multi-channel home-theater applications, such as 5.1 and 7.1 surround sound. Of course, the speakers must be self-powered, and all relevant components must be WiSA-certified, but that certification guarantees interoperability and automatic configuration between different brands of products.
Speaking of brands, WiSA has added six new members, bringing the total up to 30, with certified products now or soon to be available from Sharp, Bang & Olufsen, and XTZ as well as ODMs (original design manufacturers) Claridy Audio and Hansong. Early WiSA products are fairly high-end, such as Sharp's SD-WH1000U universal player and several B&O speakers and TVs, but WiSA expects lower-priced products to be available soon.
The organization announced at CEDIA that the next version of the WiSA specification will include the ability to dynamically allocate audio channels between a 5.1-channel home theater and multizone stereo audio. The multizone portion will support up to 32 speakers in up to seven zones from the same transmitter with individual volume control. Also, a new transmitter design is plug-compatible with older transmitters and allows transmissions up to 100 meters line-of-sight or 35-45 meters through three "American" gypsum walls (less through concrete walls). To develop and test these new systems, WiSA has rented a 3000-square-foot, 2-story house in Hillsboro, OR, and equipped it with extensive instrumentation.
WiSA presented three demos in its sound room at CEDIA. The first was a 7.1 home-theater setup with a PS3 playing Blu-rays to a Bang & Olufsen Beovision Avant 55 TV, whose onboard speaker reproduced the center channel. The other six channels were served by Beolab 20 powered speakers with integrated subwoofers, all fed 24/48 audio wirelessly from the TV via WiSA. Also demonstrated was a Sharp SD-WH1000U universal player feeding 24/96 2-channel audio to two custom-modified Klipsch Palladium P-39F speakers, each with a built-in WiSA receiver and amplifier (actually, each speaker was bi-amped with 2x250W).
Unfortunately, I didn't get to hear those two demos, but I did hear the third one, in which WiSA's new multi-zone capabilities were highlighted. The PS3 was connected to a prototype transmitter via HDMI, which sent 5.1-channel audio wirelessly to a set of XTZ Cinema-series WiSA-certified speakers. Connected to the transmitter's second HDMI input was an Apple TV playing 2-channel CD-quality audio (16-bit/44.1 kHz) from a Mac Mini, which was communicating with the Apple TV via AirPlay and an AirPort Extreme router. The transmitter sent the 2-channel audio to a pair of custom-modified Paradigm Atom monitors with WiSA receivers and internal amps in the back of the room.
Ironically, the AirPlay system was reportedly unreliable because of all the WiFi congestion, but when I heard the demo, it was working just fine. Hearing both the 5.1 movie soundtrack and 2-channel music together was a bit cacophonous—normally, the two programs would be playing in different rooms—but it ably demonstrated WiSA's new multizone capability.
WiSA is an open standard with no licensing fee. Manufacturers that wish to make WiSA-compatible products must join the association for an annual, sliding-scale membership fee that depends on the size of the company, and they must pay for independent testing and certification, which gives them the right to display the WiSA logo on their products. Currently, only Summit Semiconductor is developing chips and modules to support WiSA, but other chip makers are certainly welcome to join the party. In any event, I look forward to seeing—and hearing—more products that implement this technology.
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