From Bluetooth to Airplay: A Look at Different Wireless Speaker Protocols

Ted Kritsonis

Published: 03/27/2019 08:50:02 AM EST in Ted Kritsonis

From Bluetooth to Airplay: A Look at Different Wireless Speaker Protocols

This article originally appeared in the November 2018 issue of WiFi HiFi Magazine.

Never before has music been so easy to play from virtually anywhere in the home. The evolution from physical media to downloadable digital files, and now on to streaming services, has been complemented by the growth in speakers, and other audio products, that support wireless audio.

A notable benefit is the freedom wireless technology offers. Moving music from one room to another with a simple tap of your smartphone or voice command is the stuff of science fiction in decades past. Continuously improving home networking technology has pushed this trend, trimming the number of steps required for homeowners to communicate how and where audio plays.

Growth is palpable, except there still isn't vast uniformity in terms of protocols. Wi-Fi and Bluetooth may be the most common and well-known standards, but there are others. Some manufacturers use Wi-Fi under a different name. Others eschew Bluetooth for lack of multi-room capabilities or perceived audio fidelity, opting for alternative methods of wireless connectivity.

Consumer electronics giants are joining established audio brands in the market, as consumers more often look toward achieving seamless wireless audio in the home.

Growing and Growing

A Statista report notes that music streaming penetration hit 22.1% in 2018, with an estimated annual growth rate of 3.8%. A 2013 forecast estimated that wireless audio growth worldwide would hit US$13.75 billion by 2018. But MarketsandMarkets claims wireless audio passed US$16 billion back in 2016, with the expectation of growing at a 10% clip year-over-year through to 2023.

That discrepancy shouldn't come as a surprise. In 2013, multi-room audio hadn't fully hit "me too" territory, smart speakers weren't a thing, and wireless protocols still had room to evolve. That was also the year Google first launched its Chromecast video streaming dongle.

While a Sonos Bridge used to be required, now you can use virtually any Sonos speaker to create a mesh network once the system is connected to a home router, making multi-room audio set-ups even easier.

Smart speaker ownership in Canada hit 8% so far in 2018, with that number expected to rise further, according to Statista. December 2017 marked the first time Canadians listened to more than a billion music streams in a single week. At the time, Nielsen Music had reported skyrocketing streaming music growth of 51.6% year-over-year, with a 20% decline in single track downloads from sources like iTunes.

These figures wouldn't be possible if it wasn't for the increasing ubiquity and simplicity of the wireless protocols supporting audio gear and streaming music services. While the efficiency and speed of LTE has done plenty for smartphones out in the wild, it's the other protocols consumers use at home that have probably made a bigger difference.

Wireless in the Wild

Rather than one industry standard, manufacturers support a variety of them, though it largely depends on the use case and devices involved. For example, Bluetooth remains the most common wireless protocol for shorter-range audio streaming.

However, the nuances of Bluetooth aren't always clear to the average person. Do people shopping for headphones or speakers know the difference among the AAC, aptX, and SBC codecs? Probably not.

AAC is the lossy codec that works best with Apple products, especially iOS devices, while lossy formats aptX and aptX HD, which are owned and licensed by Qualcomm, work best with Android and everything else, and support 48kHz/16-bit and 48kHz/24-bit audio, respectively. To get the best sound, the source device should support one or both of these. If not, then the stream defaults to Subband Coding (SBC), which is of a lower quality. It's a classic case of fine print. Read closely to see which codec a speaker or headphones supports.

With AirPlay 2 support, offered in Apple's HomePod and supported by a number of other speaker manufacturers like Sonos and Bang & Olufsen (B&O), you can control multiple speakers throughout the home, and use the Siri voice assistant to control playback of tunes from Apple Music.

Wi-Fi has always been more promising, mainly because of fatter data pipes, longer range, and other protocols piggybacking off it. DLNA (Digital Living Network Alliance) was among the first to try simplifying streaming in the home. UPnP was mostly focused on getting video from a computer or storage drive over to a compatible hardware product, like a video game console or streaming box.

Even Apple's AirPlay was dependent on Wi-Fi, allowing the company's devices to push content to compatible devices, like the Apple TV or third-party speakers supporting the feature. Ditto for Google's Chromecast.

For the most part, these are similar products delivering similar features. It just comes down to ecosystem. It's not possible to use AirPlay to play something on a TV via Chromecast, or to cast content over to an Apple TV from an Android device, for instance. Sonos now supports AirPlay 2 on a few of its speakers, but it doesn't work with Chromecast or Bluetooth, using Wi-Fi instead.

Despite the limitations, manufacturers and streaming services have embraced wireless playback in greater numbers. Spotify Connect displays connected speakers on the app, regardless of if they're Wi-Fi or Bluetooth. YouTube displays both AirPlay and Chromecast icons, though it will not do so on Android devices. Netflix, Crave TV, SoundCloud, DAZN, Tidal, Google Play Music - the list of services that use wireless playback is endless.

Quality Stream

Convenience has arguably prevailed over quality when it comes to wireless audio. The quickest and most painless method usually trumps fidelity as the focal point for the average consumer. Audio enthusiasts pay greater attention to quality, but overall, audio quality of both the files and the source devices has been improving.

Bluetooth has been both celebrated and maligned. It's readily available and easy to connect, but may not always sound great, depending on the source and playback device. While better than before, it can still be prone to dropouts, and is affected by physical obstacles that could weaken the signal.

The new Gen 2i speakers from Bluesound support AirPlay 2, aptX HD Bluetooth, and Wi-Fi 5 (802.11ac) dual-band, offering the best of the best of wireless transmission methods that are available to facilitate music streaming.

"While Bluetooth doesn't necessarily tell the ‘top streaming quality' story, it's a nice feature to have built-in, as it opens up more opportunities for someone to take interest in Bluesound," says Matt Simmonds, Product Manager at Bluesound, a brand with products that support both Bluetooth and Wi-Fi. "Qualcomm's new aptX HD codec does stream at 24/48kHz, so the quality is obviously improving. The issue is having the source hardware (phone, tablet, et cetera) that's able to stream in these qualities as well. In time, this will happen."

Bluetooth 5.0 mostly focuses on making Bluetooth Low Energy (LE), a separate stream from classic Bluetooth built for small data transfers or connections, more effective. But other features have been thrown in. One, in particular, is the ability to play audio on two connected speakers at once. Such a setup would allow one phone to stream to two speakers in different rooms, or two different audio streams simultaneously to speakers or headphones from the same device.

The new standard also doubles data transfer speeds to 2Mbps, from 1Mbps in Bluetooth 4.2. It also quadruples the range to a theoretical 800 feet. The aptX codec is supposed to deliver CD-quality streams at 1Mbps, so doubling that would presumably mean better quality.

Though Bluetooth is backward-compatible, meaning a device with version 5.0 can communicate with another running an earlier version, there's no way to update it otherwise. Flagship smartphones already have it, taking care of one side of the equation. It's just the other end of the ad hoc connection that would need to support it, too.
Where Bluesound has opted to support Bluetooth as an additional feature, Sonos has shunned it from the start. The only exception was including Bluetooth LE in the Beam because "it made setup easier.

"Bluetooth is made for point-to-point connections - good for a single individual sending content from point A (e.g. a phone) to point B (e.g. a single speaker)," says a Sonos spokesperson who chose to be anonymous. "If you get a phone call, the song is interrupted. If the phone leaves the house, the music stops. We optimized Sonos for a home environment with multiple speakers, multiple rooms, and multiple people."

Why not just throw it in? The same source told WiFi HiFi that "less is more" when it comes to "simplicity and focus." If it's not perceived to make the experience better, then there's no reason to include it. Bluetooth 5.0 does theoretically offer more multi-stream flexibility, but it is still limited by range from the source device.

The Klipsch Reference RSB-8 150-watt soundbar and subwoofer boasts a myriad of wireless connectivity options, including Wi-Fi, Bluetooth 2.0, and Play-Fi.

Perhaps another reason is the lack of flexibility. Wi-Fi connectivity relies on the home network with the router being the access point. So long as the source device and speakers have a solid connection, roaming around the house doesn't matter. Sonos has prided itself as a company with speakers that enjoy greater longevity and relevance through software updates. But its claim to fame has always been multi-room audio. That has been more efficient through Wi-Fi.

When Sonos first launched, Wi-Fi was on the 802.11b standard. Dual-band routers weren't even a thing yet. The speed and throughput on both the 2.4GHz and 5GHz bands a decade ago paled in comparison to current standards with 802.11ac (and the next one, 802.11ax). Initially, Sonos required that customers use its Bridge device to create a mesh network called SonosNet when connected to the router via Ethernet.

Now, you can use any Sonos products to play the role, as mesh Wi-Fi networking is widely available. Mesh networks offer a way to broaden speed and throughput in homes, using multiple units, or nodes, that act as routers to create the mesh. The challenge is then to try using the same, or less, bandwidth to stream audio throughout a multi-room system.

Sonos says it has always designed its platform to optimize the link budget, basically a summary of the gains and losses from the medium to the transmitter. The Bridge helped maintain consistency in spite of tougher wireless conditions at the time. Now, the focus is to steadily increase the audio quality.

"The hardware radio is designed in such a way that its performance is comparable with enterprise class access points, getting the most out of the hardware and software solution possible," says the Sonos rep. "We've gotten better at this over time, as evidenced with Beam having four antennas working concurrently (4x4 802.11n technology) and being the first audio player in the world using this technology."

With dual-band setups, the more advanced standard runs on the 5GHz band, while the preceding one runs on 2.4GHz. Wi-Fi offers wide backward compatibility, which is why a Sonos speaker from 10 years ago can run on the same system as the Beam, which launched in 2018.

"Our first speakers still work," says the spokesperson. "When it comes to Bridge and creating SonosNet, you can essentially substitute any of our products that have an Ethernet connection to play that role, including a Play:1, Playbase, Boost, or Play: 5. Bridge essentially equals SonosNet, but there are now other ways to create that."

In other words, a Play:1 plugged directly into a router (or via Powerline adapter) could act as a Bridge that communicates with older speakers in the system.

DTS Play-Fi

The DTS Play-Fi ecosystem claims to have the largest collection of products in the whole-home audio space, with over 200 speakers, soundbars, set-top boxes, and receivers from dozens of brands. Long-time supporters of the ecosystem, like DISH TV, Klipsch, McIntosh, Onkyo, Pioneer, and Polk Audio, were joined by Audiolab, Mission, QUAD, Soundcast, and Wharfedale, over the last 12 months.

Play-Fi's other notoriety is lossless multi-room wireless audio streaming on any supported product from services like, Spotify, Tidal, Amazon Music, Deezer, iHeartRadio, Juke, KKBox, Napster, Pandora, Qobuz, QQ Music, SiriusXM, and SoundMachine. That can also include Internet radio stations and personal music libraries. Play-Fi relies on Wi-Fi to spread out and connect the disparate pieces together through the Play-Fi app, where users can send music or group speakers together.

Hundreds of audio products support DTS' Play-Fi ecosystem, which offers lossless multi-room wireless audio streaming from a wide range of services, as well as Internet radio stations, and personal music libraries.

The biggest selling points are arguably the interoperability, regardless of brand, and the ability to play lossless high-res files at 24-bit/192kHz. The combination means consumers can set up wireless surround sound and multi-room systems with products from different brands.

"Combining a DTS Play-Fi soundbar and any two other DTS Play-Fi-enabled speakers, consumers will be able to quickly and easily configure them as surround left and right to make a true 5.1 home theatre system," explains Dannie Lau, General Manager of DTS Play-Fi. "Unlike other solutions, we can guarantee sub-millisecond accuracy between speakers using standard Wi-Fi. That same robust, low-latency streaming technology is used with our DTS Play-Fi Headphone app, which guarantees audio synchronization with video."

Despite the broad range and functionality the platform provides, it's not clear if average consumers even know what Play-Fi is, much less what it can do. Lau says exposure is improving as well-known brands join the fray, along with devices priced from $49 all the way up to $12,000, appealing to a diverse selection of users. Lau adds that Play-Fi will soon be included in new product categories that it doesn't currently work with, but didn't elaborate further.

Even so, there are caveats to the openness. Apple Music is still missing, though AirPlay will work with Play-Fi-ready products supporting it. As of this report, only 15 products support the DTS Play-Fi Headphones feature to stream in-sync audio/video to headphones. The Windows PC application is still limited to CD-quality lossless, whereas the mobile apps for iOS, Android, and Kindle devices can do 24/192 hi-res audio.

"Retailers could benefit significantly by highlighting unique aspects of the DTS Play-Fi ecosystem," suggests Lau. "They can talk about brand interoperability without being locked into a single brand, the availability of products for different settings and scenarios, such as battery-powered speakers, AVRs, and outdoor speakers, as well as wireless headphone and AV synchronization features."

Article Tags:  wireless audio, wireless speaker, wireless protocol, bluetooth, wifi, play-fi, dts, smart speaker, whole home music, music, streaming


From Bluetooth to Airplay: A Look at Different Wireless Speaker Protocols

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