Automation and Metering
A static mix is rarely the best mix, and ears alone are not enough to trust one. Automation lets controls move over time; metering lets you watch the result with your eyes as well as your ears. This page grounds both in libsonare's automation and meter processors; for the basics see Mixing Basics.
Automation: a mix that breathes
Automation records how a control changes over time — push the vocal up half a dB in the chorus, fade a synth out over four bars, open a filter on a riser. Each control follows a curve between the points you set, and the curve shape changes the feel:
| Curve | Motion |
|---|---|
| Linear | A straight ramp between points |
| Exponential | Fast-then-slow (or slow-then-fast) — natural for fades |
| S-curve | Eased at both ends — smooth, musical transitions |
| Hold | Jumps instantly and stays until the next point |
Automation can target faders, pans, sends, and insert parameters, so the whole strip — not just level — can move.
Metering: trusting your eyes too
Rooms lie and ears tire, so a mix is also judged on meters:
- Peak / true peak — the highest level. A plain sample meter only reads the stored samples, but the waveform reconstructed between them can rise higher; true peak catches those between-sample overs a plain meter misses.
- RMS / LUFS — average level and perceived loudness, which is what listeners actually judge.
- Correlation — whether left and right agree; strongly negative values warn the mix may weaken in mono.
- Goniometer — a dot-plot of the stereo field, with left and right plotted against each other. A tall vertical blob means a mostly-mono signal, a wide horizontal spread means a wide stereo image, and a tilt warns of phase problems — width and phase at a glance.
Meters describe; they do not decide. Use them to catch problems your ears miss, not to chase numbers.
How libsonare models automation and metering
Automation is scheduled on AutomationLanes as sample-accurate AutomationEvents with an AutomationCurve (linear/exponential/s-curve/hold); an AutomationTarget points at a fader, pan, send, or insert parameter, and InsertAutomationLane automates inside an insert. Metering uses a MeterProcessor (MeterConfig) for peak/true-peak/RMS/LUFS and correlation, plus a GoniometerBuffer of GoniometerPoints for the vectorscope. All of this is real-time-safe, so automation plays back and meters update both offline and inside an AudioWorklet, with engine-side telemetry available for UI displays.
Related: Mixing Basics, Channel Strip, True Peak, Reading Mastering Meters