Load audio
Choose a browser-decodable mono, stereo or six-channel file.
Stereo to 5.1 Surround Converter
Convert mono or stereo audio to a real six-channel WAV · Preview and tune each speaker group · Runs locally in your browser
Smart DSP v2.3
Auto 5.1 Detection
Stereo Upmix
16-bit 6-ch WAV
LFE <80Hz
Surround Delay
100% Browser
This is an independent browser-based surround upmixer. The browser preview is a stereo downmix of up to the first 60 seconds of the processed six channels; the downloaded WAV contains the real 5.1 channel layout.
🎷
Drop stereo or 5.1 audio file or click to upload
MP3, WAV, OGG, AAC, FLAC, M4A — mono and stereo files are upmixed; exactly 6-channel files are preserved. Maximum 100 MB and 10 minutes.
Recommended: upload short 15–60 second parts. Long audio creates a very large uncompressed 5.1 WAV and can use substantial browser memory.
📁 File—
⏱ Duration—
🎘 Sample Rate—
🔊 Channels—
📈 Input Waveform
🧮 Auto Processing
Cinema Matrix — Center uses the stereo sum, LFE uses a low-pass filter, and surrounds use the stereo difference signal with adjustable delay.
✨ Smart Surround Processing
Smart Center Focus 70%
Front Stereo Width 110%
Rear Space 70%
Bass Level 85%
Vocal Presence 35%
Smart Center uses stereo coherence to focus common vocals and dialogue. Rear Space uses independent all-pass and multi-tap phase networks for wider, less identical surround channels.
🎘️ Frequency Crossover
LFE Cutoff (Sub) 80 Hz
Center High-Cut 8000 Hz
Center Low-Cut 200 Hz
Surround High-Cut 7000 Hz
Surround Low-Cut 200 Hz
Surround Delay (ms) 15 ms
📦 Export 5.1 Audio
Exports a real 6-channel 16-bit PCM WAV (FL, FR, FC, LFE, RL, RR — standard 5.1 order). Native 5.1 uploads are preserved; stereo uploads are upmixed. Compatible with VLC, DaVinci Resolve, Adobe Premiere, Audacity, and most DAWs. WAV is uncompressed, so it can be much larger than MP3. A final soft limiter and exact -1.5 dBFS safety ceiling are applied before WAV encoding to prevent clipped samples.
Use short clips: long audio creates a very large WAV and may use substantial browser memory.
Estimated download size: Upload a file to calculate size
Estimated download size: Upload a file to calculate size
🔊 Live Speaker Theater
🎘️ Channel Mixer
📡 Signal Flow
FL ← Left Channel (HPF >80Hz)
FR ← Right Channel (HPF >80Hz)
C ← stereo sum × selected matrix level
LFE← stereo sum low-pass at selected cutoff
LS ← stereo difference + adjustable delay
RS ← inverse difference + adjustable delay
Matrix Coefficients
Browser-based 5.1 upmixing
What this stereo to 5.1 converter actually does
This tool creates a six-channel 5.1 WAV from mono or stereo audio by deriving Center, LFE and Surround content from the source. It does not claim to recover an original studio surround mix that was never present in the source file.
Preview & tune
Choose a processing mode and adjust Center, bass, surround and channel levels.
Export 5.1 WAV
Render a six-channel 16-bit PCM WAV in standard 5.1 channel order.
Common questions
Stereo to 5.1 converter FAQs
Does this converter create a real 5.1 audio file?
Yes. The downloaded WAV contains six discrete PCM channels in the order Front Left, Front Right, Center, LFE, Left Surround and Right Surround. With a mono or stereo source, the extra channels are derived by upmix processing rather than recovered from an original studio surround master.
Can I convert MP3, WAV, FLAC, AAC or M4A to 5.1?
The tool accepts audio formats your browser can decode, including common MP3, WAV, OGG, AAC, FLAC and M4A files. Codec support can vary by browser and operating system.
Is the conversion private?
The normal conversion workflow runs in your browser. Your selected audio is decoded, processed and prepared for export on your device rather than uploaded for server-side audio conversion.
What happens if I upload a native 5.1 file?
When the browser exposes the source as exactly six channels, the tool preserves that six-channel layout and lets you adjust channel levels before exporting a new 5.1 PCM WAV.
Why is the exported WAV much larger than the original MP3 or AAC?
The output is an uncompressed six-channel 16-bit PCM WAV. Six uncompressed channels require much more storage than a compressed mono or stereo file, so a larger file is expected.
Can I preview the surround result on normal headphones?
The browser preview is a stereo downmix of the processed channels, so it helps you judge balance but does not turn two-channel headphones into six physical speakers. Use a compatible multichannel player or speaker system to verify the final 5.1 file.
Does stereo-to-5.1 conversion recreate the original movie-studio surround mix?
No. Upmixing derives Center, LFE and Surround content from the available mono or stereo source. It cannot recover separately authored studio stems that are not present in the source file.
What is the Premium Converter (Free)?
Premium Converter (Free) opens the dedicated Upmixify browser converter at upmixify.com. It is a separate free surround-audio workflow for users who want to continue in the Upmixify ecosystem.
Is there an Android app for 5.1, 7.1 and 9.1 conversion?
Yes. The official Upmixify 5.1+ Surround Audio Converter app page lists 5.1, 7.1 and 9.1 workflows, speaker-level controls, recording and supported multichannel export options. Device and format support can vary.