Audio Forge Pro

Free Stereo to Mono Fixer & Left-Ear Audio Repair Online

A free browser-based channel fixer that repairs recordings where audio plays in one ear only, or converts stereo into a centered mono track. Fix single-mic Zoom, OBS, and Skype recordings, or downmix uneven stereo audio — all in your browser without uploading audio files.

Why Is My Audio Only Playing in the Left Ear?

When a single microphone records into a stereo track (Zoom calls, OBS, Skype, or a solo XLR interface input), the voice is written to the left channel only and the right channel stays silent. Audio Forge Pro duplicates the left channel to the right with 100% phase-aligned fidelity so the voice plays out of both ears — or merges both channels into one centered mono file.

Key Features

  • Copy Left Ear to Both: 1-click repair for single-mic Zoom, OBS, and Skype recordings where the right channel is silent.
  • Copy Right Ear to Both: Mirrors the fix for right-channel-only recordings.
  • Stereo to Mono Downmix (Center Panning): Combines left and right into one centered track with 0.5 gain attenuation to prevent clipping and phase comb filtering.
  • Folder Batch Processing: Drag in an entire folder of call or stream recordings — every file is channel-balanced automatically.
  • Zero Server Uploads: 100% private in-browser processing. Your files never leave your device.

How to Fix Single-Ear Audio

1. Drag a file or a whole folder of recordings into the drop zone (MP3, WAV, M4A, OGG, FLAC, AAC). 2. Choose "Copy Left Ear to Both" for one-ear recordings, "Copy Right Ear to Both" for the opposite case, or "Downmix L+R to Mono" for a centered mono file. 3. Process and download instantly — no DAW install, no re-export workflow.

Who Needs the Stereo to Mono Fixer?

  • Zoom & Skype Interviewers: Balance mic audio that only plays from the left headphone.
  • Podcasters with Solo XLR Interfaces: Fix recordings where a single mic is wired to input 1 of a Focusrite or Behringer interface.
  • OBS Streamers: Correct commentary recorded as stereo in Windows audio settings instead of mono.
  • Video Editors: Standardize wireless-lapel-mic camera audio before importing into Premiere Pro or CapCut.

Frequently Asked Questions

Why does my microphone audio only play in my left earphone?

This happens when recording a single mono microphone (like a USB mic or XLR mic plugged into Channel 1 of an audio interface) into software configured for stereo recording (like Zoom, OBS Studio, or Audacity). The software records your voice into the Left channel and leaves the Right channel completely silent. Audio Forge Pro fixes this in 1 click by duplicating the Left audio channel to both ears.

Is the Stereo to Mono Audio Fixer completely free?

Yes — 100% free with no sign-up, no account creation, no watermarks, no file size limits, and no monthly caps. All audio processing runs locally inside your browser memory.

What is the difference between 'Copy Left to Both' and 'Stereo to Mono Downmixing'?

'Copy Left to Both' takes the left channel sound and copies it to the right channel — ideal for fixing single-mic recordings where the right channel is completely silent. 'Stereo to Mono Downmixing' combines both left and right channels into a single centered audio track — ideal for stereo recordings that sound uneven or wide.

Will downmixing stereo to mono degrade my audio quality or cause phase cancellation?

No. For single-ear fixes ('Copy Left to Both'), the left channel signal is copied with 100% mathematical fidelity. For mono downmixing, Audio Forge Pro averages the left and right channels at equal 0.5 gain each, which keeps the result within safe digital range and avoids phase comb filtering.

Does my audio file get uploaded to a remote server?

No. Audio Forge Pro operates 100% client-side using in-browser audio buffers and background threads. Your files stay on your computer and are never transmitted across the network, ensuring complete confidentiality.

How do I fix left-only audio in OBS Studio for future recordings?

In OBS Studio, open 'Advanced Audio Properties' from the Edit menu or gear icon next to your Mic/Aux input, and check the 'Mono' checkbox. This tells OBS to route single-mic input to both left and right channels automatically.

Can I fix multiple single-ear audio files in batch at once?

Yes. You can drag and drop multiple audio files or an entire folder into Audio Forge Pro. A background thread works through every file in the batch, so you can fix dozens of Zoom or podcast recordings in one go.

What file formats can I fix and export?

You can import MP3, WAV, M4A, OGG, FLAC, AAC, and WMA files. All processed files are exported as high-fidelity MP3s ready for YouTube, podcasts, and video editing timelines.

Can I normalize loudness or remove silence after fixing channel balance?

Yes! After fixing the channel balance, you can seamlessly run AI Silence Removal or YouTube -14 LUFS Loudness Normalization directly within Audio Forge Pro without re-uploading your file.

Can I normalize loudness or remove silence after fixing channel balance? Yes — continue into the AI Silence Remover or the -14 LUFS Normalizer in the same session without re-uploading. Read the full pacing and loudness guide.

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