Using your smartphone as an external speaker for your computer may seem like a waste of time until you need to output sound to a high-quality Bluetooth speaker connected to your phone, or you simply want to listen to music in another room with only your mobile device. Modern technology makes it possible to organize wireless transmission of audio streaming with minimal latency, turning your gadget into a fully-fledged remote speaker. This solution is especially useful when your laptop's built-in speakers are crackling and connecting wires to external speakers is inconvenient or impossible.
The main advantage of using a Wi-Fi connection over classic Bluetooth is the channel throughput and connection stability over distance. While Bluetooth often cuts off sound quality and is highly dependent on obstacles between devices, Wi-Fi allows for transmission lossless Uncompressed audio formats. You don't need to be a technical expert to set up such a connection, but understanding the basic principles of network protocols will help you avoid common configuration errors.
In this article, we'll explore proven methods for implementing this feature, using both specialized software and built-in operating system capabilities. We'll explore the nuances of router setup that are critical for minimizing latency and offer solutions for the most popular platforms. The key to success is that both devices are on the same subnet (same network segment), which is often overlooked when there are guest networks or split 2.4 GHz and 5 GHz frequencies.
How Wireless Audio Works
Fundamentally, the audio transmission process is based on client-server technology, where the computer acts as the signal source (server), and the phone receives this data stream. Software encodes the audio signal into a digital packet, which is then routed through a router to the recipient. The speed of this process directly depends on the quality. Wi-Fi signal and airtime congestion from neighboring networks.
There are several protocols used for streaming, each with its own characteristics. Some applications use proprietary compression algorithms to reduce latency, while others rely on standard network data transfer protocols. Understanding how your router processes these packets can help with troubleshooting.
⚠️ Note: If your router has the "Client Isolation" (AP Isolation) feature, audio transmission between devices will not be possible, as this setting prohibits data exchange between devices within the local network.
A stable connection is critical to ensure smooth playback without buffering interruptions. Even a brief packet loss can cause audible artifacts or even a complete loss of playback. Therefore, before beginning setup, ensure both devices are within range of a strong signal.
Using specialized applications: AudioRelax and similar ones
The most effective way to organize a broadcast is to use specialized software developed specifically for this purpose. The leader in this niche has long been the app AudioRelax (formerly known as AudioRelay), which offers low latency and support for various codecs. The principle is simple: you install the server component on your PC and the client component on your smartphone.
After installing the server component on your computer, the program creates a virtual audio device that becomes selectable in the system. This allows you to redirect all system audio or audio from specific applications directly to the network. Setup takes just minutes and doesn't require extensive knowledge of network infrastructure.
- 📱 Cross-platform: Support for Windows, Linux, macOS, and Android/iOS allows you to create a unified audio system from diverse devices.
- 🎚️ Flexible customization: Ability to adjust bitrate, buffering and choose between audio quality and response speed.
- 🎙️ Microphone: Some versions allow you to broadcast not only the output sound, but also the input signal from the PC microphone.
It's important to note that free versions of such programs often have limitations on runtime or audio quality. Professional use, where every millisecond of latency matters, may require a premium subscription. However, for everyday needs, the basic functionality is usually more than sufficient.
Broadcasting via media servers and UPnP/DLNA protocol
If your goal is to play music files stored on your computer's hard drive, rather than broadcasting system audio in real time, then the ideal solution is DLNAThis standard allows devices on a local network to exchange multimedia content without the need to install additional server software other than the standard Windows media server.
Windows has built-in media streaming that's easy to activate. You don't need third-party software if you simply want to listen to a collection of MP3 or FLAC files stored on your PC. Your phone acts as a renderer, reading data directly from your computer's hard drive.
Control Panel → Network and Internet → Network and Sharing Center → Media Streaming SettingsAfter activating the feature, you need to find your phone in the list of devices and allow it access. Most modern music players on Android (for example, VLC, BubbleUPnP) and iOS (for example, 8player) will automatically detect an available server and allow you to control playback.
| Parameter | Description | Impact on sound |
|---|---|---|
| Bitrate | Data per second | High bitrate improves quality, but requires a stable Wi-Fi connection. |
| Buffering | Preloading data | Increasing the buffer removes jerkiness, but adds latency. |
| Codec | Compression algorithm | AAC and Opus provide better quality at a smaller size. |
| Frequency | Hertzovka signal | Standard 44.1 kHz or 48 kHz for most applications |
This method places virtually no load on the computer's processor, as the file is simply transferred over the network, and decoding occurs on the phone's end. This makes DLNA a power-efficient solution for long music listening sessions.
☑️ Setting up DLNA on Windows
Streaming via OBS and RTMP server
For users who require maximum control over the audio stream or who broadcast audio within a video stream, using OBS StudioAlthough this is a professional streaming tool, its capabilities allow you to stream audio to your phone via a local RTMP or NDI server with minimal latency.
The method involves creating a local server that receives the audio signal from OBS and broadcasts it over the network. A player that supports network streams (for example, VLC Player), where the local stream's address is entered. This method is more difficult to configure, but it offers incredible flexibility.
You can mix audio from different sources, apply noise reduction filters or equalizers before sending it to your phone. This makes this method popular among podcasters and musicians who use their phones as monitor mixers.
⚠️ Note: Setting up a local RTMP server requires a static IP address for your computer or proper DHCP reservation settings so that the source address does not change after a router reboot.
Additionally, using the NDI (Network Device Interface) protocol allows for high-quality audio and video transmission over a local network with very low latency. To do this, you will need to install NDI Tools on a PC and a corresponding application on a smartphone.
Delay problems and their solutions
The most common problem with wireless audio transmission is audio and video desynchronization (if the video is playing on a PC) or simply a noticeable delay in response to actions. A latency of 200-300 ms may be unnoticeable for music, but it's critical for gaming or video viewing. The main cause is always a congested wireless channel or insufficient signal strength.
To minimize lag, it's important to prioritize audio traffic. Many modern routers support QoS (Quality of Service), which allows you to allocate network resources to specific devices or traffic types. Configuring QoS can dramatically improve performance when other devices are using the network.
- 📡 5 GHz band: Switch both devices to the 5GHz frequency, as it is less noisy and provides higher data transfer rates.
- 🔌 Cable connection: If possible, connect your computer to the router via Ethernet cable while leaving your phone connected to Wi-Fi. This will reduce the load on the wireless interface.
- 🚫 Disabling background downloads: Make sure that there are no heavy downloads or updates running on your devices while you are broadcasting.
It's also worth checking the power-saving settings of your laptop's Wi-Fi adapter. Power-saving mode can artificially reduce signal strength or interrupt the connection during quiet periods, resulting in audio "hiccups" when playback resumes.
How to check the delay?
Launch the stopwatch on your phone and sync it with the timer on your PC using the click sound. The time difference will show the actual latency of your configuration.
Alternative methods: Bluetooth and virtual cables
Classic Bluetooth is also worth mentioning. Despite its limitations, it remains a built-in solution that doesn't require network configuration. However, for tasks where synchronization or quality are important, it falls short of Wi-Fi. Nevertheless, for simple notifications or podcasts, it may be sufficient.
There are also solutions based on virtual audio cables, such as VB-Audio Virtual Cable In conjunction with network mixers. This method allows you to create complex audio routing within the system and send a specific channel to a network address. This is the choice of advanced users willing to spend time on fine-tuning.
Before installing such software, it is recommended to create a system restore point.
⚠️ Note: Program interfaces and codec algorithms may change with developer updates. If the menu path described differs, look for sections with similar names or refer to the official documentation for the specific application.
The method you choose depends on your specific needs: DLNA is sufficient for music, specialized low-latency applications are better for games and videos, and OBS and NDI are better for professional work.
Frequently Asked Questions (FAQ)
Is it possible to stream audio from a PC to a phone via the Internet instead of local Wi-Fi?
Theoretically, this is possible if you set up port forwarding on your router and have a static IP address, or use programs with remote access capabilities (for example, TeamViewer in audio mode). However, latency will be significantly higher, and the quality depends on your provider's upload speed.
Why doesn't the phone see the computer in the broadcast program?
Most likely, the devices are on different networks (for example, one on guest Wi-Fi, the other on the main Wi-Fi) or the Windows Firewall is blocking incoming connections. Check the network type (it should be "Private") and add the app to the firewall exceptions.
Does playing audio affect my phone's battery life?
Yes, active Wi-Fi data reception and audio stream decoding consume power. With prolonged use, the phone may become noticeably warmer and drain its battery faster than in standby mode.
Is high-definition (Hi-Res) audio supported?
This depends on the app's capabilities and the phone's hardware. Protocols like DLNA and NDI support lossless streaming, while some proprietary apps may compress the stream to reduce latency.