Stereo Field
Pan laws, width, and mono compatibility.
You have two ears roughly 17 centimetres apart. That tiny gap is enough for your brain to build a complete spatial map of every sound around you. Stereo audio exploits this by sending slightly different signals to a left speaker and a right speaker, creating the illusion that sounds exist at specific positions in space. The entire stereo field lives between those two speakers.
Pan is the simplest spatial tool: it moves a sound toward the left or right speaker by changing the volume balance between them. There is a subtlety here called a pan law. If you just turn down the left channel and turn up the right, a sound panned dead centre will actually seem louder than one panned to a side - because both speakers are contributing. Pan laws compensate for this by reducing the centre level slightly, usually by about 3 dB or 4.5 dB, so that a sound maintains the same perceived loudness wherever you place it.
Hit play and sweep the Pan control. Notice how the sound moves across the stereo image. Then try Width and Mono together to hear the difference between a wide spread and a collapsed single point.
Drag the dot to place the sound around your head. Best on headphones.
Mono vs stereo
Mono sends the same signal to both speakers. Stereo sends a different signal to each. Your brain reads the difference between left and right as spatial position - that's where "width" comes from.
Width and the Haas effect
Width controls how spread out the sound feels between the speakers. At zero width, both channels carry the same signal - this is mono. As width increases, differences appear between the left and right channels: slightly different timing, pitch, or tone. Your brain interprets these differences as spaciousness.
The Haas effect is one of the most powerful spatial tricks in audio. If the same sound arrives at your left ear just 1 to 30 milliseconds before your right ear, you perceive it as coming from the left - but it still sounds like a single source, not an echo.
Producers use this constantly: duplicate a track, delay one side by a few milliseconds, and the sound seems to widen dramatically. Below about 1 ms the effect vanishes. Above about 30 ms your brain starts hearing two separate events.
Mono compatibility
Mono compatibility matters more than most people realise. Phone speakers are mono. Many club PA systems sum to mono for the dance floor. Festival sound rigs often run mono for the crowd beyond the first few rows.
If your mix relies on stereo tricks that cancel when summed to one channel, large parts of your audience will hear something broken. Always check your mix in mono. The Mono slider above lets you hear what happens when the stereo information collapses.
Pan vs balance
Pan changes the position of a mono signal in the stereo field. Balance adjusts the relative volume of the left and right channels without repositioning them.
If you have a wide stereo recording, pan would collapse it to one side. Balance would keep its width intact while making one side quieter. Think of balance as a volume relationship between existing left and right content.
Mid/side processing
Placing sounds in the mix
Stereo placement is one of the most satisfying parts of mixing. Every sound gets a position: vocals and bass in the centre, guitars and keys spread wider, percussion scattered across the field. A well-panned mix feels three-dimensional. A poorly panned mix feels flat and crowded, like everyone in a band standing on the same spot.
1. Sweep the Pan control slowly from left to right. Notice how the sound moves across the stereo image.
2. Set Width to 100% and then drag it to 0%. Hear the space collapse to a single point.
3. Set Mono to 100%. This is what your mix sounds like on a phone speaker. Does anything disappear?
4. Try the Orbit control and close your eyes. The sound should seem to circle around your head (best on headphones).
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