Control

Stereo Width Control

Width control runs from 0 (mono) to 1.5. Learn the stereo matrix, why 0 is a mono check, what phone speakers hear, and when widening makes an edit feel bigger.

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Width is the last stage in the chain and the one with the most honest name. It makes the stereo image wider or narrower, from 0, which is mono, to 1.5, which pushes the image beyond where the original mix placed it. The default of 1.0 leaves the file as it was, and the Haze Chamber preset pushes it all the way to 1.5. Most people treat it as a "make it bigger" knob for headphones. It is that, but it is also the editor's mono check, and the mono check is the part that saves edits from sounding wrong on the phone speakers where most slowed + reverb edits will actually be heard. This page explains the maths of the stereo widener, what it does and does not do to mono compatibility, and when widening is worth it.

What Width does in signal terms

The editor splits the stereo signal into left and right, then recombines them with four gains. If the Width value is w, each output channel is built like this:

• Left out = Left x (1 + w) / 2 + Right x (1 - w) / 2
• Right out = Right x (1 + w) / 2 + Left x (1 - w) / 2

Plug in the three landmark values:

Another way to read the same matrix is in mid and side terms. The mid signal, which is what the two channels share, is (L + R) / 2 and the matrix leaves it exactly alone at every Width value. The side signal, which is the difference between the channels, is (L - R) / 2 and the matrix multiplies it by w. Width is a side-level control. At 0 the side is gone and only the mid remains. At 1.5 the side is 50% louder than it was.

Width sits after the reverb mix, so it acts on the finished sound. Because the reverb tail is stereo with different early reflections in each channel, the tail carries a lot of side information, and Width therefore has a larger effect on the reverb than on a centred vocal or a centred kick.

Zero is a mono check

Set Width to 0 and both channels become (L + R) / 2. That is precisely the signal a single phone speaker, a smart speaker or a mono Bluetooth unit produces when it sums a stereo file. Playing your edit at Width 0 on headphones lets you hear what those devices will play, without leaving the editor.

What to listen for at 0:

• Does the reverb shrink? Some of it will, because the side component of the tail cancels. If the edit goes from "huge hall" to "small room" the tail was mostly side information, and phone listeners will never hear the hall.
• Does anything disappear? Elements in the source that were panned hard or recorded with out-of-phase stereo tricks can vanish or turn hollow in mono. Nothing in this editor causes that; the mono check just reveals it.
• Does the vocal get louder relative to the music? Vocals are usually centred, so they survive mono intact while wide elements fall away. The balance can shift toward the voice.

If the mono version sounds acceptable, your edit will survive phones. If it does not, the fix is usually in the source choice or in the reverb mix, not in Width, because Width cannot change what the mid signal contains.

Mono compatibility

Here is the useful consequence of the matrix. Since the mid signal is unchanged at every Width value, the mono sum of your export is the same whether you set Width to 0.5, 1.0 or 1.5. A phone speaker plays the same thing either way. Widening does not break mono compatibility.

What widening does change is the gap between the headphone experience and the phone experience. At 1.5 a headphone listener hears a wide, enveloping reverb while a phone listener hears the mid signal only. If you set the reverb mix by ear at 1.5 on headphones, you may pick a level that feels right because the width is carrying the mood, and that level will sound flatter on a phone. Set the mix at Width 1.0 or even at 0, then widen afterwards.

The other cost of widening is headroom. At 1.5 each output channel is 1.25 times its own side plus a subtracted quarter of the other. When left and right are very different, as with a wide reverb or hard-panned instruments, peaks in one channel can rise by up to a quarter and clip. A loud master with heavy bass boost and Width at 1.5 is the combination most likely to crackle. If clipping appears when you widen, pull Width to 1.2 or 1.3.

When to widen

Widen when the listening context is headphones and the material has stereo information worth exaggerating.

• Reverb-heavy slowed edits for YouTube. Long-form listeners on headphones are the audience that gets the most from 1.2 to 1.4. The Haze Chamber preset uses 1.5 for maximum envelopment.
• Instrumentals and ambient edits. No centred vocal to protect, and pads and reverbs are mostly side information anyway.
• Sources that were mixed narrow. Older recordings and some live mixes have a small image that gains a lot from 1.2.

Keep it near 1.0 when:

• The post is for TikTok, Shorts or Reels. Playback is mostly a phone speaker. Width is inaudible there, and setting the mix at a wide setting can mislead you. Wave Drift at 1.08 is a sensible default for this.
• The source is already very wide. Modern pop masters often use stereo widening already. Pushing further sounds phasey.
• You hear a hollow or swirly quality. That is the subtracted opposite-channel content revealing phase differences in the source.

Narrow below 1.0 when:

• You want a lo-fi, vintage or intimate feel. 0.6 to 0.8 reads as old and close.
• The source has stereo problems. A narrower image hides them.
• You are checking mono. Set 0, listen, then return to your working value.

How Width interacts with the other controls

Reverb and Space. The wet signal is where most of the side information lives. More reverb mix and longer decay both mean more side content for Width to act on. Wide plus long plus wet is enormous on headphones and ordinary on a phone.

Bass. Low frequencies in most mixes are centred, so Width barely touches them. The headroom interaction is the only thing to watch.

Tone. Side information is concentrated in the mids and highs. A dark Tone with a wide image gives an enveloping, soft sound; a bright Tone with a wide image can sound airy or, pushed too far, harsh.

Speed. No direct effect.

Recommended Width by goal

Mistakes with Width

• Setting the reverb mix at 1.5. Width carries the mood on headphones, you under-mix the reverb, and the phone version sounds dry. Set the mix at 1.0, then widen.
• Expecting Width to rescue a mono source. If the file has identical channels there is no side signal to scale. Width does nothing to it.
• Widening a hard-panned source to 1.5. The subtracted opposite channel can clip or sound hollow.
• Skipping the mono check. Thirty seconds at Width 0 tells you more about how the edit will travel than any amount of headphone listening.
• Using it as a volume control. Wider often feels louder on headphones because the side gets louder. The mid, and the mono loudness, has not changed.

Width and the export

The export runs the same matrix as the preview and encodes to MP3 at 96 kbps, 32 kHz, in a web worker in your browser. MP3 joint stereo coding handles wide material reasonably at this bitrate, but very wide, very bright content is the hardest case, so a 1.5 Width with a bright Tone benefits from a good source. The export is fine for YouTube, TikTok and Shorts since they re-encode anyway. For a distribution master, use a WAV source in a DAW. The editor does not export WAV.