Understanding console fader laws: log, linear, and taper curves
A mixing console fader is not simply a volume slider with a scale printed beside it. Its gain law decides how much level change each millimetre of travel produces. Understanding console fader laws starts with separating position, gain and attenuation: a desk can offer log, linear or manufacturer-specific motion while keeping the same marked level at 0 dB. That choice shapes how quickly an engineer can find a balance, repeat it and automate it.
The terminology is slippery. Potentiometer taper describes a resistive relationship; fader law describes the intended relationship between travel and level. Both affect the movement under the hand. The useful question is not which law is best, but how much resolution is needed around unity, how the desk behaves under automation and whether the control surface agrees with its internal gain structure. Australian engineers often call this “fader feel”, a practical expression covering leverage, spacing and sensitivity.
Why fader law changes the mix
In its simplest form, a linear law makes output amplitude follow travel directly. Equal distances do not produce equal changes in decibels: a large reduction near unity can look the same on the scale as a small reduction much lower down. Specifications sometimes use “linear” differently, so check whether a manufacturer means amplitude, attenuation or decibels per millimetre.
A logarithmic law changes gain exponentially with travel, allowing equal distances to give nearly constant decibels per millimetre. With an illustrative 100 mm throw spanning +10 to -90 dB, unity would be reached at 90 mm, leaving the final 10 mm for boost. Actual consoles often mark unity at another point or switch to a separate boost section, so this example describes the principle rather than a universal specification.
Where log and linear feel different
Even spacing gives a log fader its familiar behaviour. Much of the usable range is devoted to attenuation, with finer control around quiet program material and a shorter boost range near the top. A linear law can offer finer travel around unity on some desks, but requires a longer movement for a large cut. Neither curve delivers infinite resolution; the useful question is where the engineer needs the most control.
Mechanical construction changes that feel independently of the printed scale. Long-throw faders can place more millimetres between important positions, while short travel, fader cap design and wipers affect leverage and repeatability. Wear is especially noticeable around heavily used areas. Gentle cleaning and replacement wipers can restore a smooth action, whereas oil left on a track may attract debris.
Calibration also needs to be kept separate from other console variables. This distinction matters when comparing console EQ curves: equalisation changes frequency balance, whereas fader taper controls gain over distance. Two faders can therefore feel different without their frequency response being the cause.
Taper families and signal position
Square-law attenuators are another historical family. Here the output amplitude is roughly proportional to the square of wiper travel, producing a different relationship between position and perceived level. A component sold as an audio or log taper does not, by itself, prove that the finished console follows a particular decibels-per-millimetre law. Manufacturer calibration and the surrounding circuit determine the result.
Most studio desks use a modified logarithmic law rather than a textbook endpoint, often adding gain above unity or changing spacing around frequently used positions. Term names can differ between service manuals and console folklore. It is worth checking the travel scale, whether the top position is passive unity or active boost, and what happens at maximum attenuation.
Position is only one part of the result. A closer look at console signal flow should be read alongside the fader law: a correctly calibrated control can still alter the sound if it sits before or after the active gain stage. An input attenuator and an output attenuator may have the same scale while producing different headroom, noise and channel-balance behaviour.
Passive, active and virtual controls
Passive consoles divide into two broad approaches. A resistance attenuator removes level without an active control element, usually at the input or output of a channel. Voltage-controlled amplifier designs use the fader to command a gain stage, so the mechanical law and the electronic law can be combined. Moving a fader may therefore change not just level but the operating point of a summing amplifier.
Motorised and virtual faders replace that analogue complexity with encoders, position sensors or software. The ASP8024 console places a patchbay-equipped workstation beside a DAW ecosystem, where a visible fader may control a DAW parameter, an input trim or a monitoring route rather than one summing bus. Read the documentation for that control before assuming its 0 dB position matches an older desk.
Gain staging and headroom
Headroom is where position law becomes engineering rather than preference. If an attenuator follows a summing amplifier, reducing the output cannot undo clipping that occurred earlier. Pulling a channel down before the summing stage can reduce overload risk, but may also change noise and interaction with other sources. Unity gain simply means the control passes its reference level; it does not guarantee that every circuit is operating below its distortion threshold.
Australian studios restoring vintage desks also need to account for the local 230 V, 50 Hz supply and the console’s intended internal rails. A replacement power supply should match the original design rather than merely provide the right connector. Digital channels offer a different limit again: 0 dBFS has no analogue-style boost above full scale, so a software fader may centre unity at the top even when its visual scale resembles an analogue law.
Automation and DAW workflows
Moving between hardware and a DAW creates another layer of mismatch. Virtual faders may use a logarithmic or linear amplitude mapping, and some hosts or control surfaces let the engineer choose. The same nominal 0 dB can appear at a different percentage of travel. Gain trim, a unity-gain plug-in and the monitor controller may each alter the apparent level, so matching fader positions is not the same as matching calibrated output.
Recall systems add their own constraints. Absolute mode restores a physical position; relative mode moves the fader by a calculated distance. Both need the correct law, motor calibration and channel gain reference, otherwise a scene can land on a different level even though the console reports the same number. When an engineer down under says they are “riding the fader” or “chasing the vocal”, automation is often the real subject, regardless of the curve.
Choosing and testing a curve
A log law usually suits broad mixing work because it gives repeatable resolution across a wide attenuation range. A linear law can suit a control dedicated to trim, boost or a unity-centred task. The best choice supports the room’s gain structure and the engineer’s habitual gestures, not the one with the most sophisticated label on the faceplate.
For a Melbourne live session or a Sydney mix room moving between a vintage analogue desk and DAW-based production, keep a written reference for unity, -10 dB, -20 dB and -40 dB. That record is more portable than fader position. It also reveals whether a difference comes from the law, the electronics or the monitoring path.
The Australian second-hand market makes this especially practical. Dealers and local classifieds quote Australian dollars, and listings for used mixing gear can provide a price cross-check. Buyers should still verify the travel law, service history, fader wipers, motor operation and local power requirements. Freight and rigging matter for imported SSL and Neve consoles, while regional studios in Brisbane, Perth or Adelaide may value local spares and technician access more than a marginal change in feel.
| Fader law | Position-to-gain relationship | Useful resolution | Typical role | Main trade-off |
|---|---|---|---|---|
| Linear | Amplitude follows travel; decibels per millimetre vary | Around unity or boost on unity-centred layouts | Trim, boost and predictable position mapping | Large attenuation can demand excessive travel |
| Logarithmic | Amplitude changes exponentially; decibels remain nearly even across the working range | Broad mixing range, especially during attenuation | General mixing and long-throw control | Unity and boost positions vary between manufacturers |
| Square-law | Output roughly follows the square of travel | Midrange attenuation | Passive channel attenuators | Perceived response differs from a fixed decibel scale |
| Modified console law | Manufacturer-defined mapping, often based on a log curve | Depends on marked endpoints and hardware | Matching a familiar room or desk | A shared name does not guarantee identical travel |
| Digital or motorised | Implemented through encoders, motors or software | Set by the control surface and host | DAW workflows, recall and automation | On-screen positions may not match analogue hardware |
Make the next fader move deliberate. Choose one channel, set a repeatable source at a conservative peak level, and compare the travel required for -10, -20 and -40 dB on each law available to you. Automate a short passage, save the positions, reset the session and check whether the balance returns. That practical test will reveal more than a specification sheet and give you a reference your whole team can use.
Keep the lesson close when evaluating a console, a motorised recall or a DAW fader. A curve should make the control easier to understand, not hide the signal path. Follow MixingConsole.org for more practical histories and technical explanations of the equipment behind recorded music, then carry the comparison into your next session.