Panning, Stereo Width and Mono Compatibility

Panning places each sound between the left and right speakers. Done well, it gives every part its own space and makes the mix feel wide and clear. Done carelessly, it creates a mix that collapses on a phone or a club's mono system.

What goes in the centre

Analyses of commercial mixes agree on a stable core: kick, snare, bass and lead vocal sit in the centre in practically every one. These are the most important elements, and keeping them central means they are equally loud in both speakers and survive any playback system.

Everything else can be spread out:

Typically centre	Typically spread
Kick, snare	Hi-hats (slightly off-centre), toms (across the kit)
Bass, sub, 808	Rhythm guitars (one left, one right)
Lead vocal	Backing vocals, doubles
Main hook (often)	Keys, pads, synth layers
	Percussion, shakers, effects returns

Balance the sides. If a busy guitar is panned left, put something of similar weight on the right — another guitar, a keyboard, a percussion part. Two parts doing the same job, like double-tracked guitars, should mirror each other: 70% left and 70% right.

Keep the low end mono

Bass frequencies carry most of a mix's energy. If they differ between left and right, the mix will sound lopsided, and a vinyl cutter or a club system may not reproduce them correctly. Measured mixes get wider as frequency rises: bass is central, the low mids slightly wider, the top widest.

A common practice is to make everything below roughly 100–150 Hz mono, either by panning bass parts to the centre or with a utility or imager that collapses the lows. There is no single correct number; listen for where the low end stops feeling solid.

Widening techniques and their risks

The Haas trick

Delaying one side of a mono sound by a few milliseconds makes it sound wide. Between about 2 and 30 ms, the brain hears one sound coming from the earlier side, even if the later copy is louder.

The problem is mono. When left and right are summed, the delayed copy combines with the original and cancels at regular frequencies — comb filtering. The first notch sits at 1 ÷ (2 × delay):

Delay	First notch	Then every
1 ms	500 Hz	1 kHz
5 ms	100 Hz	200 Hz
10 ms	50 Hz	100 Hz
20 ms	25 Hz	50 Hz

That's why Haas-widened parts sound thin, hollow or phasey on a phone or in mono.

Mid/side processing

A mid/side tool splits a signal into the mid (what's the same in both channels) and the side (the difference). Boosting the side widens the image; in mono, the side cancels out cleanly and the mid remains, so the sound gets narrower rather than damaged. This is a safer way to widen than Haas delay.

Keep widening off the bass and off the whole mix. Widen individual elements — pads, backing vocals, effects returns — where it helps.

Real stereo sources

The most mono-safe width comes from genuinely different parts: two separate guitar performances panned apart, two different synth layers, a stereo-recorded room. They don't cancel, because they aren't copies of each other.

Checking mono compatibility

• Mono button: switch the master to mono regularly. Parts that vanish or change tone have phase problems.
• Correlation meter: reads +1 for mono, around 0 for very wide, −1 for inverted polarity. Brief dips below zero are normal; a sustained negative reading is a fault — often a polarity-flipped mic or an over-widened part.
• A phone speaker: the final, honest check.

Pan laws differ

When you pan a sound, the DAW adjusts its level so it doesn't jump in loudness. Different DAWs use different rules — some cut the centre by 3 dB, some boost the sides instead — so the same pan settings can sit a few dB apart in different software. If you move a session between DAWs, re-check the balance.