Speakers

3 Myths About Wireless Audio Systems

Wireless audio systems don't have to compromise quality, bandwidth and interoperability. Here's how to meet your clients' wireless audio expectations.


The WiSA Association opened an authorized test center in Sunnyvale, Calif. to test and certify wireless products based on the WiSA Compliance Test Specification.
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Wireless audio is here to stay, but there are still myths in the market regarding quality, bandwidth and interoperability. Instead of designing systems that allow your clients to merely “settle” for a wireless option, integrators can design killer systems that do not compromise their client’s expectations.

According to Jim Venable, president of the Wireless Speaker and Audio (WiSA) Association, there are three common equipment myths regarding wireless audio that integrators often encounter with clients.

Myth 1: Wireless Speaker Systems Don’t Support High-Res Audio

Wireless audio systems can have the ability to play uncompressed audiophile-quality files or streams, and matching the native sampling rate is vital, says Venable. He notes that WiSA-certified home theater systems start by decompressing an original audio file or stream from its native format, such as MP3, DVD, Blu-ray Disc, CDs, or from a satellite/cable box. 

The full, uncompressed, stream is sent wirelessly to the speakers, which have built-in amplifiers.  The audio signal stays digital from the media source to the surround speakers, where it goes through a single D/A (digital to analog) conversion before being reproduced by the loudspeakers.
 
Digital filters and crossovers can be applied just before the amplifier to equalize the signals and send them to the individual high-, mid- and low-frequency drivers. Since the power amplifiers are now within the loudspeaker cabinets, they can be precisely matched to the combined impedance of the drivers and the enclosures. This gives the speaker manufacturers the ability to fine tune their amplifiers and digital crossover to give desired frequency response. 

imageThis free white paper from the WiSA Association outlines the frequency spectrum that allows a high-quality, interference-free wireless audio system to work, an overview of the sample rate, why compression isn’t needed, error detection and correction technology, speaker-to-speaker delay, and low latency required to maintain a high-fidelity wireless setup. Download

Also, the individual driver cones can be time-aligned by the manufacturer, so there is more coherence and less phase distortion near the crossover point(s). This practice of time-aligning the individual speaker cones and compression drivers within a given loudspeaker enclosure has been fairly common in professional concert sound systems for the past 20 or 30 years, but was not available to most home theater owners until now, notes Venable.

In terms of sampling rates, the ability to support multiple sampling rates is also important: from 44.1k samples per second (CD and MP3s) to 48k (DAT, HD-SDI, Digital TV, most DVDS and Blu-ray) to 96k (Dolby, DTS, SACD, DSD and DVD-Audio Discs).

“It’s that simple,” says Venable.

Myth 2: The Bandwidth is Insufficient to Maintain Fidelity

Many wireless speakers on the market share frequencies with Wi-Fi devices, Bluetooth, baby monitors, and microwave ovens, which can cause conflicts. The WiSA-compliant communication network uses a portion of the 5GHz U-NII radio band that was recently made available, with a catch. This band requires Dynamic Frequency Selection (DFS) and was previously reserved for weather and military applications. These frequencies can only be used so long as conflicts with these important services are actively avoided. 

WiSA-certified devices are required to look-ahead to determine the next unused frequency.  Conflicts are rare, but when the speaker system encounters interference from another device, it will automatically jump to the next interference-free frequency without dropping any of the audio that is playing.  Then, it will automatically begin looking for another open frequency, so it always has a backup channel to jump to.  The result is no conflicts, no dropouts and no interference.

Myth 3: Wireless Speaker Systems Are Less Flexible in Terms of Design

While architectural speakers might allow a dealer to hone in on the best sweet spot for a multichannel application or find the ideal placement in a multiroom system, wireless speakers are actually much more flexible in terms of design than their architectural brethren. Wireless bookshelf or pedestal speakers can be moved around to accommodate rearranging furniture. This allows the homeowner to always have an ideal sweet spot. Moreover, if the homeowner wants to take one of the speakers outside, it can be done too.

WiSA-compliant speakers have another trick up their collective sleeve; they can also adjust the sweet spot on the fly by using either the on-screen display or a handheld remote controller, iPad or a built-in ultrasonic transducer triangulates the center loudspeaker and sets the delays and volume levels of each loudspeaker, so they are optimized for that particular seating location.

At CEDIA 2013 Expo in Denver, Colo., from Sept. 26-29, 2013, WiSA staff will be in Sound Room 13 offering demos of wireless audio systems so dealers can get a first-hand experience. Also, WiSA has written an in-depth technical white paper on the subject that integrators can download for free here.



  About the Author

Jason has covered low-voltage electronics as an editor since 1990. He joined EH Publishing in 2000, and before that served as publisher and editor of Security Sales, a leading magazine for the security industry. He served as chairman of the Security Industry Association’s Education Committee from 2000-2004 and sat on the board of that association from 1998-2002. He is also a former board member of the Alarm Industry Research and Educational Foundation. He is currently a member of the CEDIA Education Action Team for Electronic Systems Business. Jason graduated from the University of Southern California. Have a suggestion or a topic you want to read more about? Email Jason at [email protected]

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