Precise LF Alignment Value Prediction
Calculate LF source alignment targets using crowd density and listener location as key model inputs.
Sub Alignment Audience Calculator Alpha 2026.1
Fast estimate for empty-room vs audience sub alignment using Crowd Density & Environmental Conditions
Copyright (c) 2026 Ben Pratico
Setting Descriptions
- Show Temp (deg C)
- Current in-show air temperature used in the speed-of-sound estimate.
- Show Relative Humidity
- Current in-show humidity used with show temperature.
- Inital Alignment Temp
- Temperature when you performed the empty-room alignment.
- Inital Alignment RH
- Humidity when you performed the empty-room alignment.
- Crowd-Correction Distance To Source
- Distance used to evaluate crowd-density impact on alignment. Initial alignment and atmospheric reference remain fixed at 30 m.
- Atmospheric Delay Change
- Shown for reference only. In shared-band source alignment, temperature/humidity are treated as common-mode and are not added to final DSP delay.
- Global Crowd Density
- Default density used when a zone is set to Use Global. Light = sparse audience (~0.5 to 1.5 persons/m2), Medium = typical show occupancy (~1.5 to 3.0 persons/m2), Dense = tightly packed crowd (~3.0 to 5.0+ persons/m2, strongest LF crowd effect).
- Zone Density By Distance
- Set crowd density by predefined distance bands from 0 m to 300 m.
- Relative Zone Density Adjustment
- Shifts all zone densities together by -2 to +2 steps to match real crowd changes.
- Applied Density (Zone Table)
- Final density used per zone after Global/Override selection plus relative adjustment.
- Ground Initial Alignment Delay (@30m)
- Ground sub delay captured in empty room at the known 30 m alignment reference.
- Flown Initial Alignment Delay (@30m)
- Flown sub delay captured in empty room at the known 30 m alignment reference.
- Ground Fine Trim
- Ground sub manual adjustment after measurement or listening.
- Flown Fine Trim
- Flown sub manual adjustment after measurement or listening.
- Refinement Crossover Window
- Frequency range used to include measured points in the refinement-engine best-fit delay calculation.
- Enable Refinement Engine to Final DSP
- When off (default), refinement outputs are hidden and final delay stays model-only. Turn on to apply measured refinement to final DSP.
- Theoretical vs Measured Rows
- `Initial` and `Calculated Pre Align` values are treated as 30 m empty-room reference data. Enter measured show phase/mag at the same 30 m reference to drive refinement fit.
- Crowd Preset Table
- Editable ms-at-30m values used by the calculator for each density and position.
- Baseline vs Zone-Weighted Correction
- Baseline uses only global density at 30 m; Zone-Weighted uses all zone bands up to the selected distance.
- Final DSP Delay To Set
- For each path (Ground and Flown): suggested show delay plus its own fine trim.
- Measured Refinement Correction
- Delay correction solved from measured phase-vs-frequency fitting around the selected crossover window (shown when refinement engine is enabled).
- Save PDF Report
- Exports inputs, zone profile, computed values, and presets to a formatted report.
Crowd Density By Distance Zone
| Distance Band | Density Override | Applied Density |
|---|---|---|
| 0-15 m | - | |
| 16-30 m | - | |
| 31-50 m | - | |
| 51-75 m | - | |
| 76-100 m | - | |
| 101-150 m | - | |
| 151-200 m | - | |
| 201-250 m | - | |
| 251-300 m | - |
`Use Global` follows the main `Crowd Density` selector first, then the relative adjustment is applied to all zones. Distances beyond 300 m continue using the `251-300 m` zone density.
Refinement Engine
| Path | Frequency (Hz) | Initial Phase @30m (deg) | Initial Mag @30m (dB) | Calculated Pre Align Phase (deg) | Calculated Pre Align Mag (dB) | Measured Show Phase @30m (deg) | Measured Show Mag @30m (dB) |
|---|---|---|---|---|---|---|---|
Initial delay/phase/mag references are assumed to come from empty-room alignment at 30 m. Calculated Pre Align columns are preview-only; for true refinement, enter measured show phase/mag at the same 30 m reference, then enable the refinement engine.
Crowd-Correction Distance To Source (m)
SPEED OF SOUND [ C ]
-
Air Propagation to Source
-
Atmospheric Delay Change (Show vs Empty@30m, Info)
-
Inital Alignment Air Delay @30m
-
Baseline Crowd Correction @30m (Ground)
-
Baseline Crowd Correction @30m (Flown)
-
Zone-Weighted Crowd Correction (Ground)
-
Zone-Weighted Crowd Correction (Flown)
-
Suggested Show DSP Delay (Ground)
-
Suggested Show DSP Delay (Flown)
-
Final DSP Delay To Set (Ground)
-
Final DSP Delay To Set (Flown)
-
Measured Refinement Correction (Ground)
-
Measured Refinement Correction (Flown)
-
Refined Final DSP Delay (Ground)
-
Refined Final DSP Delay (Flown)
-
Refinement Fit (Ground)
-
Refinement Fit (Flown)
-
Note: Treat as a starting preset, then confirm by measurement or listening and trim around +/- 1 to 2 ms as needed.
Crowd Correction Presets (ms at 30m)
| Density | Ground | Flown |
|---|---|---|
| Empty | ms |
ms |
| Light | ms |
ms |
| Medium | ms |
ms |
| Dense | ms |
ms |
Future Dev Plan: Smaart Phase Import
- Import MVP: Add drag-and-drop import for Smaart exported phase trace files (CSV/TXT), with a preview table and frequency/phase column mapping.
- Measurement Roles: Let users tag each trace as Ground Empty, Ground Show, Flown Empty, Flown Show, and Main reference so the app can compare like-for-like data.
- Open User Measurement Intake: Add a guided upload path for users to submit real-world traces and measurement notes so calibration datasets can expand and improve model accuracy over time.
- Signal Conditioning: Add optional phase unwrap, coherence/magnitude quality filtering, and smoothing to stabilize noisy live measurements.
- Hybrid Recommendation: Blend predicted correction (density/weather model) with measured correction and expose a confidence score plus residual error.
- Preset Learning: Store accepted measured results per venue profile so crowd-density presets improve over time from your real shows.
- Spatial Crowd Density Mapping: Use Measure Live room geometry and location data to split the audience into zones (front/mid/rear/sections) so non-uniform crowd density can be adjusted quickly by position.
- Workflow Outputs: Add one-click export of final Ground/Flown delay recommendations to CSV and a printable show-note summary.