Widen a stereo track or narrow it toward mono with one slider, from 0% to 200%, and hear the change live before you export. Free, no upload.
The stereo widener changes how wide a stereo track sounds with a single control. It splits the audio into what the two speakers share (the middle) and what differs between them (the sides), then turns the sides up or down. At 100% the track is unchanged, 200% doubles the difference for a wider image, and 0% removes it entirely, leaving mono. You hear the change as you move the slider, and the export is kept below clipping automatically.
Settings between 120% and 150% open up a mix that feels crowded in the centre without obvious side effects. Push further and the middle — usually the lead vocal, kick, and bass — starts to sound thin, and the track may lose body on a phone speaker or anything else that plays in mono. A file that is already mono has no side signal, so there is nothing to widen; the tool tells you when that is the case. Your audio never leaves your device. Mono vs stereo audio covers the basics, and for movement around the head rather than width, try 8D audio.
It uses mid/side processing. The audio is separated into the part both speakers share and the part that differs between them, and the differing part is turned up to widen the image or down to narrow it. No delay, reverb, or other effect is added.
Up to about 150 percent is usually safe. Beyond that the center of the mix, where lead vocals and bass sit, becomes weaker relative to the sides, so the track can start to sound phasey or hollow in stereo, especially on headphones. On a phone speaker or anything else that plays in mono, the extra width simply disappears, so check that the mix still works without it before sharing.
Not with this tool. A mono file has identical left and right channels, so there is no difference between them to increase. The tool will tell you if the file you load is mono. Creating a stereo impression from mono needs a different technique, such as a short delay on one side.
In the strict sense, yes. The widener changes only the side part, which cancels out when left and right are summed, so a mono speaker plays the same mid signal it did before. What does not survive is the extra width itself: the wider the setting, the bigger the difference between what you hear in headphones and on a mono speaker. The exported file can also be a little quieter overall if its level was lowered to prevent clipping.
It can. Turning up the side part raises the peaks in each channel, most of all on tracks with a lot of stereo difference. If any sample would go past full scale, the export lowers the whole file just enough to stay below it, so nothing distorts, and it never turns anything up. Narrowing toward mono cannot raise the file's highest peak. The live preview skips this step, so an extreme setting can sound a little louder there than in the exported file.