Can you play audio from two apps at once?
The ability to play audio from multiple apps simultaneously is a useful feature that many smartphone users wish they had access to. With people increasingly using their phones for multimedia activities like listening to music or podcasts while also needing to take calls or get notifications, there is demand for true multi-tasking when it comes to audio on mobile devices.
This article will explore the current capabilities and limitations of playing audio from two different apps at the same time on smartphones. We’ll look at which apps do and do not support background audio, different workarounds people use, and what future developments may enable true simultaneous audio playback from multiple sources.
Multi-Tasking Capabilities
Modern devices like smartphones and tablets are designed for multitasking with the ability to run multiple apps simultaneously. According to Computer multitasking on Wikipedia, multitasking refers to “the concurrent execution of multiple tasks (also known as processes) over a certain period of time” [1]. Operating systems like iOS and Android include features to enable efficient multitasking between apps.
For example, both operating systems allow apps to run in the background so you can switch between different apps seamlessly. This allows you to listen to music from a streaming app while responding to messages in another app. Some devices also offer split-screen modes that divide the screen to show two apps side-by-side [2]. This enables advanced multitasking by interacting with multiple apps at the same time.
Playing Audio in the Background
Android allows apps to continue playing audio even when the app is no longer in the foreground. This is enabled through the concept of “audio focus” in Android’s audio architecture. Apps request audio focus when they want to output audio, which allows Android to manage audio streams from different apps.
By implementing an ongoing notification and requesting audio focus, apps can continue playing audio in a background service even when other apps are in the foreground. Some common examples are music apps and video streaming apps that play audio when minimized or multi-tasking.
As noted in the Android developer documentation, apps should contain audio playback functionality in a separate MediaSessionService to enable seamless background audio playback. This service allows the audio to persist independently of the app’s UI lifecycle.
Mixing Audio Streams
Mixing the audio output from two different apps into one combined audio stream is possible on some operating systems, but can be challenging. Modern desktop operating systems like Windows, macOS, and Linux offer audio architectures that allow multiple audio streams to be combined into a single output using audio mixing software or virtual audio cables.
On Windows 10, third party virtual audio cable software like VB-Audio Cable or VoiceMeeter Banana can be used to patch audio streams from different apps together so they get mixed into one output device. This requires configuring each app’s audio output to use the virtual cables rather than the default audio device. The virtual cable outputs are then routed to a mixing application to produce the combined audio stream.
Linux systems using PulseAudio have native support for audio stream mixing. The pavucontrol GUI audio mixer allows combining multiple application audio streams by selecting the output device for each. ALSA also supports mixing via the asym plugin, but requires more complex configuration.
On macOS, applications like Blackhole or Loopback can create virtual audio devices to facilitate routing and mixing audio from multiple sources. The audio streams are mixed internally and output as a single combined device.
So in summary, mixing two audio streams into one output is possible on most desktop OSes, but requires third-party tools and careful audio routing configuration to combine outputs into a single mixed stream.
Apps with Background Audio Playback
Many popular apps allow you to keep listening to audio even when you switch to another app or lock your screen. This is especially common for apps focused on playing music, podcasts, videos, and other audio content. Some examples include:
Spotify – The music streaming app lets you keep listening to songs, playlists, albums etc. in the background across iOS and Android devices (1).
YouTube Music – Google’s music app supports background playback for both free and paid subscribers on iOS and Android (2).
Pandora – The internet radio app allows you to keep listening to stations in the background on iOS and Android unless you’re on the free ad-supported tier (3).
Apple Podcasts – You can listen to podcast episodes in the background across iPhone, iPad, Mac and Apple Watch (4).
Overcast – This popular third-party podcast app has background audio support on iOS (5).
Audible – Amazon’s audiobook app lets you keep listening to books even when you lock your phone or switch apps on iOS and Android (6).
So most major audio apps designed for music, podcasts, radio etc. allow you to keep listening even when you multitask or lock your device. This makes it easy to mix and match different audio sources.
Using Multiple Apps Simultaneously
Most modern smartphones allow you to play audio from multiple apps simultaneously in some capacity. For example, you can play music from a streaming service like Spotify while also playing a podcast from an app like Pocket Casts or a navigation app like Google Maps for turn-by-turn directions. The Spotify music will continue playing quietly in the background while the podcast or navigation instructions play overtop.
Smartphones achieve this by assigning audio streams different priority levels through a system called “audio focus” (1). Music apps are usually set to have a low priority audio focus that gets ducked under higher priority streams. This allows short audio cues like navigation prompts to play overtop music without stopping it completely.
On Android, apps like Samsung SoundAssistant provide more control over audio focus and allow you to choose to play multiple streams at equal levels simultaneously (2). This could allow you to play music while also listening to a sports broadcast, for example. On iPhone, limitations in iOS mean you are more restricted in playing true simultaneous audio from multiple sources.
Limitations
As multiple users have pointed out, there are technological limitations that prevent smartphones from playing audio from two different apps simultaneously (Why can’t smartphones play multiple audio sources at once?). This is due to the audio architecture on mobile operating systems like iOS and Android, which only allow one app to have control of audio output at a time. This is known as “audio focus.”
When multiple apps try to play audio at the same time, the OS will prioritize one app while muting or ducking audio from the other apps. There are also limitations when streaming audio from cloud services. Platforms like Amazon Music only allow streaming on a certain number of devices concurrently per account, such as 6 devices at once on the family plan (Amazon Music Unlimited Streaming Limits). YouTube Premium similarly restricts simultaneous music streaming to just one device (YouTube Premium streaming limits).
Workarounds
There are a few potential workarounds to play audio from two different sources simultaneously, though their effectiveness may depend on the specific device and apps being used:
On Windows 10, it’s possible to use the “Stereo Mix” feature to combine audio streams from multiple apps into one device in the sound settings. This allows playing audio from two apps at once, though adjusting their volumes independently may be difficult.[1]
On mobile devices like iPhones or Android phones, using multiple physical devices can allow playing two audio sources simultaneously. For example, listening to music on your phone while using a Bluetooth speaker for navigation instructions from Google Maps.
Some apps may have workarounds built directly into their settings, like allowing audio playback in a small pop-out window. This could work for combining a music app with a podcast or audiobook app, though experience may vary across platforms.
While imperfect, these workarounds can help approximate the ability to play two audio sources together when full native support is lacking.
Future Possibilities
Mobile operating systems may add better support for simultaneous audio playback in the future. Apple and Google have both introduced new wireless audio transmission protocols – LE Audio and Auracast – that allow for synchronized playback across multiple devices and connections.
According to Energy5, future wireless audio connectors will likely support multi-room audio streaming that allows users to play audio on multiple speakers simultaneously. As mobile devices adopt LE Audio and Auracast, they may gain the ability to mix and synchronize audio from multiple apps.
Immersive and spatial audio is another area of innovation. As described in this Analog Devices article, future audio systems may leverage computer vision and head tracking to create more realistic 3D soundscapes. Mobile OSes could integrate these technologies to provide an immersive audio experience using multiple audio streams.
Overall, simultaneous multi-app audio playback seems technically feasible with emerging wireless protocols. As these new standards are implemented, mobile OS developers may choose to expose mixing and synchronization capabilities to apps and users. This could allow seamless blended audio from different sources, unlocking new creative possibilities.
Conclusion
In summary, the ability to play audio from multiple apps simultaneously varies across devices, platforms, and apps. While true audio mixing is limited, it is possible to play audio from one app in the background while using another app in the foreground. Apps like music streaming services often have background audio playback capabilities, allowing you to listen while using other apps. However, background audio may pause if resources are constrained. There are some workarounds like using multiple devices, but full multi-app audio mixing remains constrained by hardware and software limitations. As mobile operating systems continue to evolve, we may see enhanced multi-tasking audio abilities in the future. But for now, seamless audio mixing across apps remains somewhat elusive. The key takeaways are:
- Background audio playback is possible but may be interrupted
- Music streaming apps often support background audio
- True mixing of audio across apps is limited
- Workarounds exist using multiple devices
- OS and hardware restrictions constrain capabilities
- Multi-app audio mixing may improve in the future
In conclusion, while playing audio from two apps at once has some limitations currently, we can expect improvements in multi-tasking audio functionality over time across mobile platforms.
