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Stereo to Surround

Upmix a stereo file to a surround sound format

Upmixes stereo audio into a 5.1-style layout. Front left/right are preserved, while center, surround, and LFE channels are synthesized with adjustable strength. Useful for creating immersive playback from stereo sources or prepping content for multi-speaker setups.

Click to upload file or drag and drop file here

Maximum file size: 200MB Supported formats: audio/*

0 0.6 1

Strength of the synthesized dialog/center channel.

0 0.5 1

Ambience sent to surround speakers.

0 0.4 1

Amount of low end routed to the LFE channel.

Key Facts

Category
Media
Input Types
file, range, select
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

The Stereo to Surround tool converts stereo audio files into a 5.1 surround sound format. It preserves the original front channels while synthesizing center, rear, and LFE channels with adjustable levels, ideal for enhancing audio for immersive playback or multi-speaker systems.

When to Use

  • •To create a surround sound experience from stereo music or audio tracks.
  • •When preparing audio content for multi-speaker setups like home theaters.
  • •To upmix stereo files for immersive listening on surround sound systems.

How It Works

  • •Upload your stereo audio file in a supported format.
  • •Adjust the center, rear, and LFE channel levels using the provided sliders.
  • •Select your desired output format from options like WAV, MP3, or FLAC.
  • •Process the file to generate the surround sound version.

Use Cases

Enhancing stereo music tracks for a home theater system.
Converting podcast audio to surround sound for immersive listening.
Preparing audio for video games or VR applications that require multi-channel audio.

Examples

1. Upmixing a Music Album for Home Theater

Audiophile
Background
You have a favorite stereo music album that you want to experience in surround sound on your home theater system.
Problem
The stereo mix doesn't utilize the full potential of your 5.1 speaker setup.
How to Use
Upload the stereo audio file, set Center Level to 0.7 for clear vocals, Rear Level to 0.6 for ambient effects, and LFE Level to 0.5 for bass. Choose FLAC as the output format for high quality.
Example Config
Center Level: 0.7, Rear Level: 0.6, LFE Level: 0.5, Output Format: FLAC
Outcome
The resulting surround sound file provides an immersive listening experience with enhanced center channel for vocals and ambient rear channels.

2. Preparing Podcast Audio for Immersive Playback

Background
A podcast producer wants to offer a surround sound version of their episodes for listeners with multi-speaker setups.
Problem
Standard stereo podcasts lack spatial depth and immersion.
How to Use
Upload the stereo podcast episode, adjust Center Level to 0.8 to emphasize dialogue, Rear Level to 0.3 for subtle background ambiance, and LFE Level to 0.2 for minimal bass. Output in MP3 format for compatibility.
Outcome
The podcast is converted to a 5.1 surround format, making it more engaging for listeners with surround sound systems.

Try with Samples

audio, file
Copyright-Free AAC Audio Samples
High-quality AAC encoded audio samples for testing and development, featuring nature sounds and meditation music with excellent compression
preferred input family audio
audio
WebRTC Real-Time Communication Samples
Comprehensive WebRTC samples for peer-to-peer audio/video communication, data channels, screen sharing, and signaling server implementation
preferred input family audio
audio
Copyright-Free MP3 Audio Samples
Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
preferred input family audio
audio
Copyright-Free WAV Audio Samples
Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
preferred input family audio
audio

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FAQ

What audio file formats can I upload?

The tool accepts any audio file format supported by your browser, such as MP3, WAV, AAC, and more.

How do I adjust the surround channel levels?

Use the sliders for Center Level, Rear Level, and LFE Level to set values between 0 and 1.0.

What is the maximum file size allowed?

The audio file must be under 200 MB.

Can I choose the output format?

Yes, you can select from WAV, MP3, AAC, M4A, OGG, Opus, or FLAC.

Does this tool work with mono audio files?

No, it is designed for stereo audio files to upmix to surround sound.

API Documentation

Request Endpoint

POST /en/api/tools/stereo-to-surround

Request Parameters

Parameter Name Type Required Description
audioFile file (Upload required) Yes -
centerLevel range No Strength of the synthesized dialog/center channel.
rearLevel range No Ambience sent to surround speakers.
lfeLevel range No Amount of low end routed to the LFE channel.
outputFormat select No -

File type parameters need to be uploaded first via POST /upload/stereo-to-surround to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-stereo-to-surround": {
      "name": "stereo-to-surround",
      "description": "Upmix a stereo file to a surround sound format",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=stereo-to-surround",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]