Open the same session in Pro Tools, Cubase, and Reaper. Same audio, same fader, pan all the way to center. Solo each track. They will not be the same loudness. Depending on settings, you can see up to a 3 dB spread between hosts on a center-panned mono source. This is not rounding error and it is not a bug — it is each DAW choosing a different point on a real engineering tradeoff that has no universally correct answer.
If you have ever moved a session between hosts and felt that the balance was suddenly off, you have already heard pan law in action. This is what is happening underneath.
The two-channel problem
A mono signal panned to one stereo position is sent to two output channels with two gain coefficients, gL and gR. The pan law is the function that decides what those coefficients are at every position. Mathematically simple, perceptually hostile.
There are exactly two clean ways to define "panned to the middle":
Equal amplitude: gL + gR = 1. At center, both sides get 0.5. The two channels add up to the original signal level.
Equal power: gL² + gR² = 1. At center, both sides get √0.5 ≈ 0.707, which is -3 dB. The two channels add up to the original signal power.
These two definitions disagree about what "constant loudness across the pan range" means, and they disagree because acoustic reality disagrees with itself depending on the listening context.
Why both definitions are correct (in different rooms)
In a fully reverberant field — think a normal listening room with hard walls — uncorrelated sounds from two speakers sum in power, because the reflections decorrelate the signals before they reach your ears. Two speakers each playing at -3 dB combine to give you 0 dB perceived loudness. Equal-power panning keeps things constant in this world.
In an anechoic chamber, or for highly correlated mono content reaching a listener at the sweet spot, sounds sum in amplitude. Two speakers playing the same signal at -6 dB combine to 0 dB. In this world, equal-amplitude panning keeps loudness constant — and equal-power panning makes the center position 3 dB louder than the sides.
Real mixing happens somewhere between these two extremes. Some content is highly correlated (a snare summed to mono, then panned). Some is decorrelated (a wide stereo synth pad). No single law is correct for both.
What the numbers in your DAW actually mean
The "-3 dB" or "-2.5 dB" label refers to the center attenuation — how much each channel is reduced when a signal is dead center.
- 0 dB pan law (equal amplitude): No attenuation at center. Each channel gets 0.5. Correct for fully correlated content. Sounds 3 dB hot at center on uncorrelated content.
- -3 dB pan law (equal power, also called constant-power): Each channel gets 0.707. Correct in reverberant fields. Sounds 3 dB quiet at center if the playback environment is anechoic and content is correlated.
- -4.5 dB pan law: A compromise between the two, historically associated with SSL consoles. Picks a midpoint that is wrong by 1.5 dB in either direction.
- -6 dB pan law: Each channel gets 0.5 and the gain is squared additionally. Used in some film and surround mixing contexts.
The math for equal-power panning is sin/cos based. For pan position θ ranging from 0 (hard left) to 1 (hard right):
gL = cos(θ × π/2)
gR = sin(θ × π/2)At θ = 0.5, both come out to cos(π/4) = sin(π/4) = √2/2 ≈ 0.707 = -3.01 dB. The identity sin²(x) + cos²(x) = 1 is what guarantees constant power across the entire sweep.
What each major DAW actually does
This is where it gets messy.
Pro Tools historically defaulted to -2.5 dB through version 8, and made it variable from version 9 onwards. The -2.5 dB value is a compromise between -3 dB (equal power) and 0 dB (equal amplitude), tuned by ear over years of feature-film mixing where rooms are not fully reverberant but are not anechoic either.
Cubase defaults to equal power on mono tracks — but here is the catch: stereo tracks in Cubase use a balance control, not a pan control, with 0 dB attenuation at center regardless of the project pan law. Drag a mono file to a stereo track and the law you think you set silently does not apply.
Logic uses -3 dB equal power, configurable in project settings.
Reaper ships with a non-standard curve: 0 dB at center, rising slightly through the sweep before returning to 0 dB at the extremes. It is configurable to anything you want, but the default is not equal-power and not equal-amplitude. It is its own thing.
Ableton Live uses equal-power panning and is not user-configurable.
Same source, same fader, same pan position — different output level, in some cases by several dB. This is also why bouncing stems and reimporting them into a different host can change the balance even when nothing else changed.
The mono-compatibility trap
Equal-power panning has a less-discussed consequence. Take a mono kick drum, pan it center with a -3 dB law. Each channel now contains the kick at -3 dB. Sum to mono — the two correlated signals add coherently and you get back 0 dB. Fine.
Now take a stereo synth pad, decorrelated between L and R, and route it through the same -3 dB pan law as a "mono" signal. Each channel still loses 3 dB at center. But because the content is decorrelated, summing to mono adds incoherently — you get -3 dB in the mono fold-down. The pad gets quieter on a mono speaker, the kick does not. Mix balance changes when checked in mono.
This is not theoretical. Broadcasters and club PA systems still encounter mono playback. If your mix sounds balanced on a stereo monitor but the bass disappears on a mono speaker, pan law on decorrelated low-end content is one of the suspects worth checking.
Practical implications
- When importing sessions across DAWs, the pan law setting is part of the mix. Check it before assuming a mix translated cleanly.
- When designing plugins that do their own panning (anything with a pan knob, autopanner, mid-side widener), pick a pan law and document it. Users will ask which one.
- When mixing for film or surround, be aware that LCR or 5.1 systems use different center-channel logic entirely — the stereo pan law you trust does not extend to multichannel without modification.
- When summing many panned mono tracks, equal-power keeps the perceived overall level stable as instruments move around the field. Equal-amplitude does not. This is why most DAWs ship equal-power as a default — it is the safer bet for most modern mixing workflows.
The fact that "centered" can mean four different gain values across hosts is not a flaw to be fixed. It is each host taking a position on a question with no clean answer: how correlated is your content, and how reverberant is the room it will be played in. Different defaults for different assumed users.
Knowing which assumption your DAW is making is the part that turns it from a hidden surprise into a tool you can use.