Evolution of Streaming

Bluetooth, AirPlay, AirPlay Audio, Google Cast, Spotify Connect

Nowadays streaming music has two meanings; either you stream content from the internet to your device or you stream music from your device to your wireless speaker or headphone. In both cases there is a source and a destination. Until recently the source has been a audio player (medium: vinyl, cassette, CD or media: flac, mp3…) and the destination were stereo speakers/headphones connected via an auxiliary audio cable (3.5mm headphone jack). But with the introduction and evolution of home audio streaming solutions, this has changed and the cable is replaced by a wireless connection. With the recent hype in multi-speaker setups, let’s take a look at the existing wireless audio solutions, how they evolved and how they compare.


Bluetooth logo blueprint and deconstruction.

Like USB, Bluetooth is standard that can be used for many different purposes such as document transfer as well as audio playback. In case of both technologies, their respective protocols have evolved over the years while staying backwards compatibly. Bluetooth uses the A2DP (Advanced Audio Distribution Profile) to support different audio codecs such as SBC (Low Complexity Subband Coding) and aptX. The aptX codec uses a better real-time audio data compression algorithm that delivers audio quality comparable to CD’s all while maintaining an unnoticeable audio latencies (40 ms), thus the traditional arguments of bluetooth delivering bad, out-of sync audio do no longer apply. Without going into further details of the protocol, let’s say that the Bluetooth protocol enables audio transmission to speakers and headphone while also being able to send media controls from the receiver to the transmitter such that you can control volume and play/pause from your headphones for instance.

Analogous to USB, Bluetooth seem like an invisible cable between two devices, which is exactly what it is; a direct wireless connection between two endpoints without an intermediate hub. This means that you can only connect two devices with Bluetooth and audio splitting/sharing is not possible. Thus Bluetooth is a valid option for headphones but multi-room speaker setups can only be achieved using Wifi. One advantage of Bluetooth over Wifi stays that it is more power efficient and it works without an existing network, which comes in handy when using your mobile Bluetooth speaker on the beach.

Using Wifi brings all of the advantages of wide and local area networking (WAN/LAN). This means access to the internet but also home and office networks can be used to share data such that music can be stored on a local server and be accessed using DLNA. We will further explore the options to stream audio to wifi enabled speaker on the same local network.


AirPlay is a wireless technology developed by apple which allows to transmit Audio and Video from your iDevice or Mac computer to other devices such as the apple TV. Initially released as AirTunes in 2004 it only supported audio and it was only possible to stream music from iTunes and iPhone to apple branded devices such as the AirPort Express. This in turn can be connected to any speaker via its combined analog–optical audio mini-jack such that you can turn any speaker into an AirPlay-enabled unit. AirPlay transmit the audio over wifi meaning that both devices need to be connected to the same local network. It wasn’t until 2010 that 3rd party speaker manufacturers released speaker with an AirPlay receiver built-in such as the iHome. Since September 2010 AirPlay can also be used to send video from your apple devices to an apple TV and since June 2011 display mirroring is also supported. AirPlay works with any audio sources (online/local) as it supports system wide audio streaming on any apple manufactured devices.

To avoid lagging audio, due to a congested or slow network, the AirPlay protocol introduces a buffer time of about 2 seconds before the audio is played on the speaker. This delay would of course make video audio play out of sync, however apple manage to fix this problem by delaying the video playback by the same amount of time. This is only possible due to apple’s tight control over the each system that is able to output Airplay audio. Due to apple’s ecosystem AirPlay works best with iTunes and apple music as well as the iPhone and the apple watch.


Sonos is one of the first speaker manufacturers to build wireless enabled speaker combined with their app and ecosystem. They released their first Digital Music System (SP100) in 2005 which was composed of a hub and a controller with a screen (before smartphones and apps even existed). Nowadays the music playback needs to be controlled via their app which in turn can be connected to music streaming services such as Spotify, Deezer, TuneIn and others. Sonos speaker are also multi-room capable meaning that the same audio can be played synchronously by different Sonos units in different rooms connected to the same wireless (or wired) network. The app thus forwards the audio from any of the available services to one of the Sonos speakers. This speaker then acts as the controller, connected via a mesh network to all the other speakers, to distribute and synchronize the audio playback between them.

Since their tight ecosystem between the speaker and app, customers tend to acquire multiple Sonos speaker to extend their home audio setup. Due to this very successful business strategy, many companies started copying the app + multi-room wireless speakers strategy such as Denon (Heos) , Bose (SoundTouch) , Teufel (Raumfeld) , Samsung , Bluesound … The resulting market fragmentation pushed some of these manufacturer to support additional streaming options such as Bluetooth, Spotify Connect, AirPlay or Google Cast in addition to their own wireless solution.

Spotify Connect

Spotify , the popular music streaming service that launched in 2008, has introduced Spotify Connect in 2013. This is a feature that allows you to play and control your Spotify playback on your computer with your phone, or vice versa, by choosing a playback destination in the Spotify app. It also supports the streaming of music to Spotify Connect enabled speakers. As Spotify has all of its 30 millon songs readily available on its server they can stream them to any internet connected device. When “streaming” music to your speaker using Spotify Connect from your phone or computer, the songs are effectively streamed directly to your speaker without passing through your device. This leaves your phone to be only the remote of the music such that, when you battery dies or you leave the house, the music continues playing on your speaker! Spotify has not yet announced plans for multi-room support of Spotify Connect but considering the heavy competition they are probably working on it . You can also add Spotify Connect support to any of your existing dumb speaker using devices such as the the Gramofon or even the Amazon Echo Dot .

Google Cast

More recently Google has been working on their own solution of audio and video streaming with the advantage of system integration into Android as well as Google Chrome. Opposite to apple, Google introduced Google Cast (in 2013) first as a video-only streaming dongle to attach to your TV.

It wasn’t until 2015 that they announced the Chromecast Audio, which also has a combined analog–optical audio mini-jack, to add music streaming capabilities to yours speakers. In 2016 they started rolling out cast enables speakers through partnerships with different manufacturers. Through the development of Android, Google already has the tools and APIs in place to make it easy for app developers to streaming support to their app. Cast support is already existing in apps such as youtube, Netflix, Spotify, Deezer etc. on both Android and iOS.

An interesting outcast from this list is Amazon with services such as Amazon Music and Amazon Prime Video, it would make sense to have streaming support for those as well. However due to the ongoing conflicts between Amazon and Google over Amazon using their own App Store on their Fire tablets instead of the Play Store, they came up with their own streaming solution called Fling with SDKs available for Android and iOS.


Even more so than with headphones, I believe that the future of speakers is wireless and we will see a lot of innovation in this area in the near future. Between the outlined systems there is no clear winner but it comes down to your own priorities for your home audio setup;

  • Do you want to go wireless, even when no wifi network is around; choose Bluetooth.
  • Do you want to stream audio from any source without using a dedicated app; choose AirPlay (iPhone & Mac) or Google Cast (Android & apps).
  • Do you want multi-room support; use Sonos (or similar) or Google Cast.
  • Do you use Spotify a lot and don’t want to control your music through yet another app; use Spotify Connect.

To turn any of your existing speakers into smart/connected units you can use a Bluetooth dongle , Airport Express (for AirPlay), Chromecast Audio (for Google Cast) or the Gramofon (for Spotify Connect).

How does your current home audio setup look like? Please comment and share your opinion and advice!

P.S.I have created the Logo decomposition myself in illustrator, feel free to contact me if you want the vector files.