How to Convert Stereo to Mono MP3
By Alexander Grouch
Updated September 22, 2017
Items you will need
Although we often think of stereo recordings as a technological step forward over the mono format, certain producers have historically preferred mono over stereo. Especially in the early days of stereo, many producers viewed stereo as a bit of a gimmick and spent most of their time perfecting the mono mix. Take a listen to Brian Wilson's production work on The Beach Boys' PET SOUNDS in both mono and stereo and you're likely to hear the more forceful impact of the mono recording over the stereo recording. Plus, if you know you'll be listening to music on only one headphone, it's nice to have all instruments mixed in a single speaker. Learn how to take your stereo MP3s and convert them to the mono format.
Download Audacity. Audacity is a free music editing program you will need to convert your music from stereo to mono. Once you download Audacity, install it on your hard drive.
Run Audacity and import the music you want to convert. To do this, click on "File" and select "Open." Then select the file you want to convert to mono. Make sure the file you are converting is already in stereo.
Look at the box that appears after you import your file. You should see blue waveforms. To the left of the waveforms, you will see a bunch of numbers and other settings in a box. In the top left corner of the box, locate the arrow (which is to the left of the 1.0 number).
Click the arrow and select "Split Stereo Track" from the drop-down menu. Now you will notice that track has been split into left and right channels that you can control.
Click the arrow by the top (Left channel) waveform (this will also be to the left of top waveform's 1.0 marking). Select "mono" from the drop-down menu.
Click on the lower (Right channel) arrow. This will be located to the left of the lower waveform's 1.0 marking. Select "mono" from the drop-down menu. At this point, the boxes to the left of the top and bottom waveforms should both say "mono." If either still says "right" or "left," ensure that you followed the above steps and switched each channel to mono in the drop-down menu.
Export your now mono song by clicking on the File tab and selecting one of the export options. Choose the directory you want to export the file to and you're done.
Audacity cannot export music as MP3's on its own because MP3 is a patented format that can't be used in free programs. However, Audacity does recognize and work in tandem with other MP3 encoders. To export your mono file as MP3s, download one of these recognized encoders: for Windows users, download LAME and find the file entitled lame_enc.dll, for Linux users, download LAME and find the fine entitled libmp3lame.so, for Macintosh users, download LAMElib. You can download all these encoders at Audacity's website (see Resources below). Once installed, you'll see "export as MP3" as an option under File. Click "Export as MP3," find the directory you want to save it to and export.
Since you'll be taking sounds that are spread between two channels and merging them into a single channel, certain sounds could become quite loud in the mix. You can adjust the intensity of the left and right channels before converting them to mono to compensate for unpleasant results.
Alexander Grouch is a freelance screenwriter, journalist and children's book author. He currently writes music reviews for "The Red Alert." Grouch has visited all 48 contiguous states and plans to document his journeys in a travelogue. He earned a Bachelor of Arts in Africana studies from Brown University.