Multi-Track Gain Curve Laboratory

AuraGainCurveLab 50-Engine Rack

Fifty independent gain-scaling engines, each with a unique curve algorithm. Switch to Align Mode for flat descending gains, or invert polarity on every Nth engine. All processing is local — no audio leaves your browser.

Master Controls

Idle · 50 engines ready

Global Transport

Master Source (all engines)

Master Duration (all engines)

Engine Mode

Align Step Size

Polarity Invert (every Nth)

Master Monitor Volume (per-engine)

20%

Master App Volume (overall mix)

80%

Master Output: −∞ dB

⚙️ Safety Settings

All safety features are enabled by default. Uncheck to disable. These protect against clipping, feedback, and sudden loudness spikes.

Master Limiter A hard dynamics compressor on the master bus with a −6 dB ceiling. Prevents output clipping no matter how many engines run simultaneously.

Mic Safety Interlock When any engine uses Live Mic: caps master volume at 30%, disables Start All, and shows a persistent headphone warning banner.

Concurrent Engine Cap Limits Start All to a maximum of 8 simultaneous engines. Prevents the worst-case 50× stack that can overwhelm speakers and the audio thread.

Aggregate Loudness Meter Displays the summed RMS level of all running engines in the master panel. Flashes amber near −6 dB and red above −1 dB.

Soft-Start Ramp Each engine fades its monitor volume from 0 to target over 100 ms when starting. Eliminates sudden pops and spikes on engine start.

Solo Mode Only one engine audible at a time. Starting a new engine automatically stops all others. Ideal for A/B comparison without stacking loudness.

Auto-Ducking When multiple engines run simultaneously, each engine's monitor volume is proportionally reduced using a square-root law so total perceived loudness stays roughly constant.

Feedback Detection Analyses mic input for persistent tonal peaks in the 2–8 kHz feedback zone. If detected for 12 consecutive frames, all mic engines are auto-muted and switched to tone.

Session Volume Memory Remembers your last Master App Volume for each source type (tone, mic, noise) in localStorage. Automatically restores it when you switch sources.

Feature	Default	What it protects against
Master Limiter	ON	Clipping & distortion from stacked engine outputs
Mic Safety Interlock	ON	Acoustic feedback loop when using microphone input
Concurrent Engine Cap	ON (8 max)	Audio thread overload and speaker damage from 50 parallel sources
Aggregate Loudness Meter	ON	Unintentional cumulative loudness creeping above safe levels
Soft-Start Ramp	ON	Transient pops and sudden volume spikes on engine start
Solo Mode	OFF	Prevents loudness stacking by allowing only one engine at a time
Auto-Ducking	ON	Proportional volume reduction prevents the "50×20% pile-up"
Feedback Detection	ON	Auto-mutes mic engines when tonal ringing (feedback) is detected
Session Volume Memory	ON	Recalls safe volume levels per source type to reduce repeated user error

📱 Mobile Background Audio

These features keep audio playing when you switch tabs or apps on mobile (Android Chrome / iOS Safari). They cannot be disabled — they are core to the engine runtime.

Feature	How it works
Silent Keeper	A near-silent looping buffer source prevents the browser from optimising away the audio thread when the tab is backgrounded.
Media Session API	Registers the page as an active media session with the OS, reducing the chance the browser kills audio on background.
Visibilitychange Handler	When the tab becomes hidden, requests a screen wake lock. When visible again, auto-resumes a suspended AudioContext.
2-Second Heartbeat	A background interval checks AudioContext state every 2 seconds and force-resumes if the browser suspended it.
iOS Touch Unlock	Listens for the first touch/click/key on the page to unlock the AudioContext, which iOS Safari requires before playback.
Pageshow Event	On iOS, the pageshow event fires when returning from the app switcher — used to detect and resume a frozen AudioContext.

🚫 Intentionally Excluded

The following feature was considered but deliberately not implemented because it provides false confidence rather than real safety.

Feature	Why excluded
Hardware Headphone Check	Browsers cannot reliably detect whether headphones are connected. The `devicechange` event only reports enumeration changes, not headphone state. On mobile, this is even less reliable. A "headphones detected" message would give users false confidence and could encourage unsafe mic use without headphones.