Absolute Zero

Contact

• Discord: https://discord.gg/9yb7hcEsmG
• Beta Feedback: beta@altitude.audio
• General: contact@altitude.audio
• Website: https://altitude.audio

AUTHORIZATION — Sign Up, Log In, and Register

Authorize Absolute Zero for free beta access by creating an account (or signing in) and registering. Your license does not expire, but builds do. If you encounter authorization issues after updating, simply renew your license—no purchases required.

Quick start

1. Open Absolute Zero. The Authorization overlay appears automatically on first launch.
2. Choose Sign Up (first time) or Log In (existing account).
3. After signing in, press Register to activate your license and unlock.
4. You're authorized. If a new build requires re‑authorization, sign in and press Renew License.

Sign Up

• Enter Full Name, Email, and Password.
• Submit to create your account.
• You’ll be prompted to sign in next.

Log In

• Enter your Email and Password and sign in.

Register for Beta

• After signing in, press Register.
• Your license is issued and activated automatically.
• The bottom bar status updates to confirm authorization is active.

Renew License

• If you experience authorization issues after updating, open the Account view while logged in.
• Press Renew License to re‑authorize.
• To authorize additional machines, log in and press Renew License on each one.

Email Updates (Optional)

• You may opt‑in to receive beta updates and announcements via the Email Updates toggle.
• This can be adjusted during registration or from the Account view.

Quick Start Guide

Getting Started in 5 Minutes

• 1. Install & Authorize

  • Install Absolute Zero with the provided installer.
  • Launch your DAW or the standalone app.
  • Complete the authorization flow when prompted.

• 2. Load a Preset

  • Open the preset browser.
  • Choose any factory preset.
  • The preset loads the full limiter configuration automatically.

• 3. Play & Adjust

  • Start playback through Absolute Zero.
  • Watch the meters and gain reduction.
  • Turn the Drive control up/down to shape limiting intensity.
  • Keep an eye on output level for healthy headroom.

• 4. Explore

  • Try different presets and sidechain combinations to hear the range.

Installation & Resource Locations

Overview

Absolute Zero includes both a standalone application and a VST3 plugin for macOS and Windows.

Installation Paths

• macOS

  • Installed resources: ~/Music/altitude/

• Windows

  • Installed resources: C:\ProgramData\Altitude\
  • Application binaries: C:\Program Files\Altitude\

Authorization

After installation, authorize the product via the built‑in login and beta registration flow.

Log In Interface

If you encounter any issues, contact contact@altitude.audio.

Architecture Overview

Modular Research Platform

Absolute Zero is a modular limiter designed for research and real‑world production. It supports a large matrix of configurations and can achieve deep gain reduction (down to roughly −2 to −3 dB RMS) while preserving clarity and musicality.

Core Architecture

Dual‑Sidechain Processing

Two independent sidechains analyze the signal in parallel:

• Sidechain 1 (Primary)
  Computes the main gain reduction based on the input signal.

• Sidechain 2 (Secondary)
  Analyzes how the signal would look after Pass 1 (the “limited” view) and computes a second gain reduction.

Both gain reductions are then combined and applied to the original signal in a single stage. You get the analytical benefits of cascaded limiting—without the cumulative artifacts and phase shifts of literally chaining two hard processors.

Sidechain Technologies

• ARIA PASS1
  Advanced envelope detection with configurable max filtering; transparent, musical response; strong stereo image retention.

• SIMPLE
  Clean, efficient, and CPU‑light; configurable knee; ideal for transparent peak control.

• STANDARD
  Feature‑rich with auto‑envelope detection, crest‑factor awareness, and smoothing; balanced between transparency and control.

• ENHANCED
  Maximum configurability; advanced max filtering with running averages, holds, and long windows; built for extreme scenarios.

Multiband Mode

Frequency‑dependent limiting with:

• Four bands and independent thresholds.
• Configurable crossover reconstruction methods.
• Tone balance controls.
• Multiple reconstruction strategies to suit program material.

Adaptive Gain Systems

• Input Adaptive Gain
  Pre‑conditioning that optimizes the drive into the limiter.

• Output Adaptive Gain
  Post‑processing that stabilizes level without flattening dynamics.

Safety & Monitoring

• Safety Limiter
  Independent brick‑wall protection that prevents output from exceeding 0 dBFS.

• Real‑Time Monitoring
  Comprehensive meters and visualizations to validate behavior quickly.

Processing Flow

1. Input stage (conditioning)
2. Input Adaptive Gain
3. Limiter Pass 1 (single or multiband)
4. Limiter Pass 2 (optional secondary wideband)
5. Soft Safety (configurable)
6. Output Adaptive Gain
7. Hard Safety (final brick‑wall at 0 dBFS)

Peak Detection Modes

• Instant
  Zero‑latency peak detection for the snappiest response.

• Windowed (Lookahead)
  Smoother, predictive behavior for more transparent control.

User Interface Layout

Plugin Overview

Absolute Zero is organized into modular panels so you can work quickly at the surface, then dive deeper when needed.

Navigation System

Use the left‑side Navigation Panel to open or hide the main areas:

• GRAPHS — Visualization and metering tools
• LIMITER — Primary control surface
• MULTI — Multiband curve editing
• DATA — Performance monitoring
• INPUT — Input adaptive gain with power toggle
• TEST — Limiting verification tools
• HELP — Context help strip (shows hints for the control under your mouse)
• METER — Integrated input/output meters and DRIVE/GR with sliders

Bottom Bar

The bottom status bar provides quick access to session-wide controls and status:

• Language — Select the UI language. Changes apply instantly and persist with the session.
• Account — Open the Authorization/Account overlay to sign up, log in, or renew the beta license.
• Tooltips (TOOLTIP toggle) — Enable or disable popup tooltips near the mouse.
  • Backed by parameter tooltip_enabled (default: ON)
  • Disabling popup tips does not affect the HELP panel (see below).
• Status — License status indicator (Licensed / Unlicensed).

Help & Tooltip System

Absolute Zero provides two complementary ways to view control hints:

• Popup Tooltips — Small popups near the cursor appear after a short delay when TOOLTIP is enabled in the Bottom Bar.
• HELP Panel — A persistent help strip at the bottom of the interface that mirrors the hint for the control under your mouse.

Notes

• Popups are controlled by TOOLTIP (parameter: tooltip_enabled).
• The HELP panel works independently of TOOLTIP and can remain visible even when popups are disabled.
• Tips are localized. Changing the language in the Bottom Bar updates both popup tips and the HELP panel immediately.

Workflow suggestion

• Keep TOOLTIP ON while learning. Disable popups later and rely on the HELP panel for an uncluttered workflow.

Main Interface Panels

GRAPHS

Standalone visualization windows for in‑depth analysis:

• Vectorscope
• Polar Sample
• Polar Level
• Five FFT windows
• Metering
• Waveform
• Loudness

LIMITER

Where you spend most of your time. Exposes the technical parameters that shape how the sidechain is built and responds.

• Dual‑pass configuration (Pass 1 & Pass 2)
• Algorithm selection (ARIA, SIMPLE, STANDARD, ENHANCED)
• Timing controls (attack, release, lookahead)
• Channel link and bypass
• Soft Safety and Hard Safety controls
• Multiband mode for Pass 1 (tone balance, reconstruction power, frequency‑dependent controls)

Note: Drive is part of the metering workflow rather than this panel.

MULTI

Curve editing for mapping threshold vs. drive when raw math doesn’t give the musical result you want.

DATA

Real‑time performance metrics.

• CPU usage
• Buffer performance
• (Future) Optimization helpers

INPUT

Input adaptive gain with power toggle:

• Automatic level detection
• Intelligent gain staging
• "Perfect drive" estimation
• Content‑aware analysis

TEST

Diagnostic tools to validate limiting and inspect envelopes:

• Limiting effectiveness
• Envelope behavior
• Signal verification
• Performance benchmarks

HELP

Context‑sensitive documentation strip.

• Shows a concise description of the control currently under your mouse.
• Lives at the bottom of the interface (above the status bar).
• Toggle with the left‑side HELP navigation button.
• Localized: text changes with the Bottom Bar language selector.
• Works independently of the TOOLTIP toggle (the HELP panel can show hints even if pop‑up tooltips are disabled).

When you want fewer pop‑ups on screen, turn off TOOLTIP in the Bottom Bar and leave HELP enabled for continuous guidance.

METER

Integrated metering column with input/output controls and drive/gr display.

• Three sections: INPUT, OUTPUT, and DRIVE (gain reduction).
• Each section includes responsive meters (peak and RMS) and a dedicated slider:
  • INPUT — Pre‑limiting trim.
  • OUTPUT — Post‑limiting level.
  • DRIVE — Controls overall compression intensity; GR meters fill top‑down for easy reading.
• Uses internal visualization for smooth ballistics and accurate readouts.
• Toggle with the left‑side METER navigation button.
• Layout toggle: Click the up/down arrow in the DRIVE section to switch between vertical column layout and horizontal row layout.

Interface Workflow

• Quick Operation — Start in the LIMITER panel.
• Deeper Control — Use MULTI when you need frequency‑dependent mapping.
• Monitor — Open GRAPHS and DATA to verify performance and behavior.
• Optimize — INPUT features assist with drive staging.
• Verify — TEST helps confirm limiting quality before print.

Panel Controls and Parameters

Navigation Panel

The Navigation Panel lets you build a clean workspace by showing only the panels you need. Each button toggles a panel on/off, remembers its state, and highlights when active.

Buttons

• GRAPH — Toggle standalone visualizers (Vectorscope, FFT, Polar, etc.)
• LIMITER — Toggle the primary control surface
• MULTI — Toggle the curve editor
• DATA — Toggle performance metrics
• INPUT — Toggle input adaptive gain (power toggle enables/disables)
• TEST — Toggle verification tools
• HELP — Toggle the help strip at the bottom of the window
• METER — Toggle the integrated meters and I/O/DRIVE sliders (right column)

Tips

• Start simple — Work in LIMITER first.
• Add as needed — Enable MULTI, DATA, and TEST for specialized tasks.
• Performance — Hiding unused panels keeps the UI snappy.

LIMITER Panel — Modular Signal Processing Architecture

The LIMITER panel is a modular surface that scales from simple to advanced. Enable only what you need, and the panel lays itself out intelligently—columns appear, scroll, and resize so you always have a clear view of your chain.

Layout and navigation

• Dynamic columns
  Columns arrange themselves as you enable modules. The panel scrolls horizontally when needed and adapts from compact to full width.
• Navigation controls
  Six toggle buttons control column visibility. Each limiter slot has its own Algorithm dropdown.
• State persistence
  Your column states and configurations are saved with presets.

Workflow patterns

• Minimal (2 columns)
  Limiter Slot 1 + Output/Tone.
  Ideal for quick limiting, low CPU, clean workflows.
• Standard (3 columns)
  Global + Limiter Slot 1 + Output/Tone.
  Ideal for mastering and enhanced peak behavior.
• Advanced (4–5 columns)
  Global + Limiter Slot 1 + Output/Tone + Limiter Slot 2 + Safety.
  Ideal for complex material, broadcast, demanding masters.
• Maximum (6 columns)
  Everything enabled with Auto Output for intelligent chains.
  Ideal for automated, template‑driven sessions.

Like assembling a studio rack, you can build exactly the chain your material needs—from transparent single‑pass limiting to sophisticated dual‑stage dynamics with intelligent protection.

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Column Parameters Reference

GLOBAL Column (Column 0)

The GLOBAL column sets system‑wide behavior—threshold reference, channel linking, and peak detection strategy. These choices shape how every downstream stage behaves.

• Threshold
  Master reference level for the entire system.
• Ch Link (Channel Link)
  How much left/right influence each other during gain reduction.
• Peak Detect
  Choose the detection style:
  • INSTANT — Fast, low‑latency, great default.
  • WINDOW — Windowed analysis for smoother, more predictive response.
    Enables extra controls when selected:
  • Buffer Length — Size of the detection window (larger = smoother, higher latency).
  • Hold Samples — Hold time to stabilize detection and avoid flutter.
• Buffer Defense
  Additional buffer‑safety logic for stability on stressed systems.
• Animation
  UI animation processing; disable to save a little CPU during heavy sessions.

Global settings apply to both limiter slots and establish the system’s overall character.

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LIMITER SLOT 1 Column (Column 1)

The first limiting stage. Choose the algorithm that fits the material; the column adapts to show only the relevant controls.

• Algorithm (Dropdown)
  ARIA PASS1, SIMPLE, STANDARD, or ENHANCED.

ARIA PASS1

Original ARIA behavior with refined peak analysis and envelope filtering.

• Attack / Release — Response timing.
• Lookahead — Predictive smoothing.
• LOW PASS (toggle) — Enables envelope low‑pass filtering with:
  • Cutoff — Filter cutoff frequency.
  • Slope — Roll‑off steepness (e.g., 6–48 dB/oct).

SIMPLE

Straightforward, efficient limiting with musical knee.

• Attack / Release — Response timing.
• Knee — Softer/harder onset around threshold.
• Lookahead — Transparent peak anticipation.

STANDARD

Feature‑rich with content‑adaptive timing.

• Lookahead / Attack / Release — Core timing.
• Smooth — Overall GR smoothing.
• Auto Atk / Auto Rel (toggles) — Content‑aware timing.
• Auto Trans — Transition time for auto logic.
• Auto Env Mode — Where the auto analysis happens:
  • AUTO PRE — Before limiting.
  • AUTO POST — After limiting.

ENHANCED

Maximum control with running averages and deep analysis windows.

• Lookahead / Attack / Release — Core timing.
• Avg Size — Running average window (larger = steadier).
• Avg Weight — Emphasize recent vs historical samples.
• Max Length — Depth of max‑filter analysis.
• Max Hold — Hold time for detected maxima (reduces flutter).

Slot 1 shapes the program’s character first; your choice here colors every stage that follows.

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L1 MULTIBAND Column (Column 2)

Frequency‑dependent control for Slot 1’s output—tone shaping, band behavior, and reconstruction.

• Tone Balance — Overall tonal tilt/weighting.
• Freq Response — Contour of the resulting spectrum.
• K Power — Reconstruction power factor.
• Intensity — Global processing intensity.
• Freq Attack / Freq Release — Timing scales across bands.
• METHOD — Reconstruction strategy:
  Minimum, Weighted, RMS, Peak‑Aware, Energy Conservation.
  Weighted is a solid default; Energy Conservation for added punch.
• TONE (toggle) — Enable multiband/tone processing.
• SOFT OUT (toggle) — Gentler output behavior.
• Safety (toggle) — Extra protection against overs and artifacts.

Usage notes:

• Use for complex material that needs frequency‑aware behavior.
• Correct tonal shifts introduced by limiting.
• Prepare the signal cleanly if you plan to enable Slot 2.

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LIMITER SLOT 2 Column (Column 3)

A second limiting stage for the most demanding material. It operates after L1 MULTIBAND and uses the same algorithm family as Slot 1.

• Algorithm (Dropdown)
  ARIA PASS1, SIMPLE, STANDARD, or ENHANCED.
• PASS 2 (toggle)
  Master enable for the second stage.

ARIA PASS1 (Slot 2)

• Attack / Release / Lookahead — Secondary timing.
• LOW PASS (toggle) with Cutoff and Slope — Same envelope filtering approach as Slot 1.
• PASS 2 (toggle) — Stage on/off.

SIMPLE (Slot 2)

• Attack / Release / Knee / Lookahead — As in Slot 1.
• Threshold — Independent threshold just for Slot 2.
• PASS 2 (toggle) — Stage on/off.

STANDARD (Slot 2)

• Lookahead / Attack / Release / Smooth / Auto Trans — As in Slot 1.
• Auto Atk / Auto Rel (toggles) — Content‑aware timing.
• Auto Env Mode — AUTO PRE vs AUTO POST for the second stage.
• PASS 2 (toggle) — Stage on/off.

ENHANCED (Slot 2)

• Lookahead / Attack / Release — Core timing.
• Avg Size / Avg Weight / Max Length / Max Hold — Same advanced analysis controls, tuned for the second stage.
• PASS 2 (toggle) — Stage on/off.

Column Type System

Absolute Zero’s LIMITER panel is built from fixed and optional columns. Keep the essentials visible, and add optional stages as your material demands.

Fixed Columns

• Column 1 — LIMITER SLOT 1
  Always present. Core limiting stage with selectable algorithm type.
• Column 2 — L1 MULTIBAND
  Always visible. Essential tone and frequency‑dependent controls for Slot 1’s output.

Optional Columns

• Column 0 — GLOBAL
  System setup and peak detection strategy. Enable for enhanced control and stability.
• Column 3 — LIMITER SLOT 2
  Secondary limiting stage. Enable for complex or demanding program material.
• Column 4 — AUTO OUTPUT
  Intelligent output management and level matching. Enable for automated workflows.
• Column 5 — SAFETY
  Final brick‑wall protection. Enable for critical prints and absolute peak control.

Algorithm Selection Matrix

Each limiter slot supports four algorithms, tuned for different use cases.

ARIA PASS1 — Transparent Peak Control

• Characteristics: Ultra‑transparent, minimal coloration, strong stereo image retention.
• Core controls: Attack, Release, Lookahead, Low‑pass (Cutoff, Slope).
• Best for: Mastering, clean program material, invisible control.

SIMPLE — Musical Dynamics Control

• Characteristics: Soft‑knee, efficient, musical response.
• Core controls: Attack, Release, Knee, Lookahead (Slot 1); Threshold (added in Slot 2).
• Best for: Mix bus work, gentle shaping, vintage‑style limiting.

STANDARD — Advanced Envelope Control

• Characteristics: Program‑adaptive behavior with auto envelope detection.
• Core controls: Attack, Release, Lookahead, Smooth, Auto Atk/Rel, Auto Trans, Auto Env Mode (PRE/POST).
• Best for: Complex material, broadcast applications, adaptive processing.

ENHANCED — Maximum Flexibility

• Characteristics: Running‑average analysis with extended max filtering.
• Core controls: Attack, Release, Lookahead, Avg Size, Avg Weight, Max Length, Max Hold.
• Best for: Demanding masters, surgical control, creative effects.

Interface Modularity

Dynamic Column Management

• Automatic Layout: Columns arrange dynamically based on enabled modules
• Intelligent Scrolling: Interface scrolls horizontally to reveal newly enabled columns
• Adaptive Width: Panel width adjusts from 280px (minimal) to 630px (full configuration)

Navigation Controls

• Column Toggles: Six navigation buttons control column visibility
• Algorithm Dropdowns: Independent algorithm selection for each limiter slot
• State Persistence: All column states and configurations save with presets

Workflow Optimization

• Quick Access: Common configurations require minimal column management
• Progressive Complexity: Advanced features appear only when needed
• Visual Feedback: Color-coded columns and clear signal flow indicators

Practical Applications

**Minimal Setup** (2 Columns)

• Limiter Slot 1 + Output/Tone
• Perfect for: Simple limiting tasks, CPU efficiency, clean workflows

**Standard Setup** (3 Columns)

• Global + Limiter Slot 1 + Output/Tone
• Perfect for: Professional mastering, enhanced peak detection

**Advanced Setup** (4-5 Columns)

• Global + Limiter Slot 1 + Output/Tone + Limiter Slot 2 + Safety
• Perfect for: Complex program material, broadcast compliance, demanding mastering

**Maximum Setup** (6 Columns)

• All columns enabled with Auto Output for intelligent workflows
• Perfect for: Automated mastering chains, template-based processing

The LIMITER panel's modular architecture provides unprecedented flexibility while maintaining intuitive operation. Like connecting hardware modules in a professional studio rack, you can craft the exact processing chain your material demands, from simple transparent limiting to complex multi-stage dynamics control with intelligent automation.

Column Parameters Reference

GLOBAL Column (Column 0)

The GLOBAL column sets the tone for the entire system: it defines your threshold reference, how channels interact, and how peaks are detected. Set it once to match your session style, and every downstream stage follows suit.

• Threshold
  Master reference level for limiting across the system.

• Ch Link (Channel Link)
  How much left and right channels influence each other during gain reduction.

• Peak Detect
  Choose the core detection style:

  • INSTANT — Fast, low‑latency, a solid default for most material.
  • WINDOW — Windowed analysis for smoother, predictive behavior.
    When WINDOW is selected, two supporting controls appear:
  • Buffer Length — Size of the analysis window (larger = smoother, higher latency).
  • Hold Samples — Short hold to stabilize detection and avoid flutter.

• Buffer Defense
  Additional buffer‑safety logic for extra stability on stressed systems.

• Animation
  UI animation processing. Turn it off to reclaim a bit of CPU during heavy sessions.

Tip:

• Use INSTANT when tracking or for percussive, low‑latency work. Switch to WINDOW when you want smoother behavior and can afford a little more lookahead/latency.

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LIMITER SLOT 1 Column (Column 1)

The first limiting stage. Select the algorithm that fits the material, and the column adapts to show only the relevant controls.

• Algorithm (Dropdown)
  ARIA PASS1, SIMPLE, STANDARD, or ENHANCED.

ARIA PASS1

Original ARIA behavior with refined peak analysis and optional envelope filtering.

• Attack / Release — Response timing.
• Lookahead — Predictive smoothing for cleaner peak handling.
• LOW PASS (toggle) — Adds envelope low‑pass filtering with:
  • Cutoff — Filter frequency.
  • Slope — Roll‑off steepness (e.g., 6–48 dB/oct).

Best for:

• Clean, transparent control with minimal coloration.

SIMPLE

Straightforward, efficient, and musical—great when you want results fast.

• Attack / Release — Core timing.
• Knee — Softer/harder onset around threshold for musical shaping.
• Lookahead — Transparent peak anticipation.

Best for:

• Mix bus work, gentle shaping, and low‑CPU sessions.

STANDARD

Feature‑rich with content‑adaptive timing.

• Lookahead / Attack / Release — Core timing.
• Smooth — Global GR smoothing (higher for less chatter).
• Auto Atk / Auto Rel (toggles) — Content‑aware timing.
• Auto Trans — Transition time for auto logic.
• Auto Env Mode — Where the auto analysis happens:
  • AUTO PRE — Before limiting (default).
  • AUTO POST — After limiting.

Best for:

• Complex program material and broadcast‑style consistency.

ENHANCED

Maximum control and stability via running averages and deeper analysis windows.

• Lookahead / Attack / Release — Core timing.
• Avg Size — Running average window (larger = steadier).
• Avg Weight — Emphasize recent vs historical samples.
• Max Length — Depth of the max‑filter analysis.
• Max Hold — Hold time for detected maxima (reduces flutter).

Best for:

• Demanding masters and surgical, highly controlled results.

Note:

• Slot 1 sets the character for everything that follows—choose the algorithm here with intention.

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L1 MULTIBAND Column (Column 2)

Frequency‑dependent control for Slot 1’s output—tone shaping, band behavior, and reconstruction. Use it to correct tonal shifts, shape the spectrum, and prepare a clean signal for dual‑stage workflows.

• Tone Balance
  Overall tonal tilt/weighting across the spectrum.

• Freq Response
  Fine contouring of spectral balance.

• K Power
  Power factor for reconstruction (energy distribution).

• Intensity
  Global processing intensity.

• Freq Attack / Freq Release
  Attack/release scaling across frequencies—how quickly bands respond and recover.

• METHOD
  Reconstruction strategy tuned to program material:
  Minimum, Weighted, RMS, Peak‑Aware, Energy Conservation.
  Weighted is a strong default; Energy Conservation tends to feel punchier.

• TONE (toggle)
  Enables multiband/tone processing.

• SOFT OUT (toggle)
  Gentler output behavior and smoother transitions.

• Safety (toggle)
  Extra protection against overs or reconstruction artifacts.

Usage notes:

• Reach for L1 MULTIBAND when the program calls for frequency‑aware control—e.g., taming sibilance while preserving low‑end power.
• If you plan to add Slot 2, use this stage to hand off a balanced, well‑behaved signal.
• Start with METHOD = Weighted, then explore Peak‑Aware or Energy Conservation if you want different energy profiles.

LIMITER SLOT 2 Column (Column 3)

A second limiting stage for demanding material. Slot 2 runs after L1 MULTIBAND, analyzing the already‑shaped signal and applying additional control where needed. Use it when a single pass doesn’t fully tame transients or when you want a distinct second character.

• Algorithm (Dropdown)
  ARIA PASS1, SIMPLE, STANDARD, or ENHANCED (same family as Slot 1).

• PASS 2 (toggle)
  Master enable for the entire second stage.

Notes:

• Keep PASS 2 off until you’ve balanced tone and dynamics with Slot 1 + L1 MULTIBAND.
• Enable PASS 2 when you need extra headroom control, stricter compliance, or a contrasting envelope character.

ARIA PASS1 (Slot 2)

Clean, refined control with optional envelope filtering—mirrors Slot 1’s ARIA approach, but voiced for post‑multiband material.

• Attack / Release — Secondary response timing.
• Lookahead — Predictive smoothing for cleaner peak handling.
• LOW PASS (toggle) — Adds envelope low‑pass filtering with:
  • Cutoff — Filter frequency.
  • Slope — Roll‑off steepness (e.g., 6–48 dB/oct).
• PASS 2 (toggle) — Stage on/off.

Best for:

• Polishing “nearly there” results without adding weight or grit.

SIMPLE (Slot 2)

Efficient, musical behavior with an additional threshold for independent level control in the second stage.

• Attack / Release — Core timing for the secondary pass.
• Knee — Softer/harder onset around threshold.
• Lookahead — Transparent peak anticipation.
• Threshold — Independent threshold for Slot 2 (decoupled from global/Slot 1).
• PASS 2 (toggle) — Stage on/off.

Best for:

• Fine‑tuning overall loudness handling after tone is set; glue without fuss.

STANDARD (Slot 2)

Feature‑rich, program‑adaptive timing—ideal when the post‑multiband signal is complex and you need controlled consistency.

• Lookahead / Attack / Release — Core timing.
• Smooth — Global GR smoothing (higher for less chatter).
• Auto Atk / Auto Rel (toggles) — Content‑aware timing.
• Auto Trans — Transition time for auto logic.
• Auto Env Mode — Where the auto analysis happens:
  • AUTO PRE — Before second‑stage limiting (default).
  • AUTO POST — After second‑stage limiting.
• PASS 2 (toggle) — Stage on/off.

Best for:

• Broadcast‑style reliability and material with mixed transient/sustained content.

ENHANCED (Slot 2)

Maximum stability and control via running averages and deep analysis windows—tuned for the second stage’s role.

• Lookahead / Attack / Release — Core timing.
• Avg Size — Running average window (larger = steadier).
• Avg Weight — Emphasize recent vs historical samples.
• Max Length — Depth of max‑filter analysis.
• Max Hold — Hold time for detected maxima (reduces flutter).
• PASS 2 (toggle) — Stage on/off.

Best for:

• Surgical refinement and maintaining a tight envelope under stress.

Parameter interactions

• PASS 2 dependencies

  • PASS 2 = OFF: Slot 2 is fully bypassed; signal passes through.
  • PASS 2 = ON: The selected algorithm’s controls become active.

• Algorithm consistency

  • Each variant shows only its relevant controls (plus PASS 2).
  • Switching the dropdown swaps parameter sets, but the stage position stays fixed.

Workflow tips

• Shape first, control second
  Use Slot 1 + L1 MULTIBAND to get the spectral and macro‑dynamics right; use Slot 2 for stricter headroom and envelope polish.

• Pick complementary characters
  Pair a transparent Slot 1 with an adaptive Slot 2 (e.g., ARIA → STANDARD) for musical yet consistent results.

• Threshold strategy
  If you need level separation between stages, use SIMPLE in Slot 2 for its independent threshold.

• Latency and feel
  Favor INSTANT‑style behavior (via algorithm/timing choices) when immediacy matters; use lookahead, smoothing, and ENHANCED‑style windows for more graceful behavior when latency is acceptable.

AUTO OUTPUT Column (Column 4)

An intelligent post‑processing stage that keeps output levels consistent while adding a gentle safety net. It analyzes the already‑limited signal and applies adaptive gain to keep things steady without flattening the mix. Labeled “SOFT SAFETY” in the UI.

• SOFT OUT (toggle) Master enable for the entire stage.

• Block Size Analysis window size for automatic gain.
  Larger = steadier decisions; smaller = faster reaction.

• Overlap Window overlap for smoother transitions.
  Higher = smoother, slightly more CPU.

• Peak Smoother Smoothing for peak tracking.
  Higher = cleaner, less twitchy gain changes.

• RMS Smoother Smoothing for RMS tracking.
  Higher = more consistent loudness behavior.

• Limiter Release Recovery time for the built‑in soft safety limiter.
  Fast = transparent; slower = silkier return.

• Max Gain / Min Gain Bounds for automatic adjustment.
  Max Gain caps upward boosts; Min Gain caps downward attenuation.

• Crest Comp (Crest Compensation) Balances peak vs RMS influence.
  Higher = more transient‑aware; lower = more sustained‑level focus.

Interactions:

• SOFT OUT must be ON for any processing here to apply.
• Block Size and Overlap work together to define the “feel” of the analysis window.
• Peak vs RMS Smoothers let you tune response to transient vs sustained energy.
• Limiter Release only affects the soft safety behavior at this stage.
• Max/Min Gain define the playground—auto gain never goes beyond these limits.

When to use:

• You want level consistency without a hard ceiling.
• You’re printing stems or references and need reliable loudness across tracks.
• You want a soft “auto trim” after creative limiting is set.

Tips:

• Start with moderate Block Size (e.g., mid‑range) and low‑to‑medium overlap.
• Increase Peak/RMS smoothing when material feels too “nervous.”
• Use a conservative Max/Min range for critical prints; widen it for creative bounce‑downs.

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SAFETY Column (Column 5)

Final, transparent brick‑wall protection at the output. This is your “HARD SAFETY” stage—an absolute ceiling so nothing escapes above 0 dBFS.

• SAFETY (toggle) Master enable for the stage.

• Attack How quickly the hard safety reacts to overs.
  Faster = stricter peak control.

• Release How quickly gain returns after an event.
  Faster = more transparent; slower = smoother but more audible.

• Knee Shapes the transition around the fixed safety threshold.
  Softer knee for less abrupt behavior.

Design notes:

• Threshold is fixed at 0.0 dBFS for true brick‑wall behavior.
• This stage sits at the very end of the chain and should normally be inaudible.

When to use:

• Final prints, broadcast compliance, and any deliverable where clipping is not an option.
• Projects with variable upstream gain where occasional spikes might slip through.

Tips:

• Keep Attack fast and Release moderate for “set and forget” transparency.
• If you hear the safety working often, reduce upstream output or revisit Slot 1/Slot 2.

MULTI Panel — Threshold vs Drive Curve Editor

Shape how threshold behaves as you turn up Drive in multiband mode. The MULTI panel lets you draw an adjustment curve so the limiter responds exactly how you want across the 0–20 dB Drive range. Use it when the default math is close but not quite musical for your material.

Panel structure

• Mode tabs ARIA PASS1, SIMPLE, STANDARD, ENHANCED.
  Each tab has its own independent curve and settings.

• USING UI / MATH ON toggle

  • USING UI: Edit the curve directly by dragging points.
  • MATH ON: Use built‑in math instead of the UI curve (editor is dimmed and disabled). When MATH ON is active, the graph overlays “USING MATH FUNCTIONS” as a reminder.

Graph layout

• X‑axis (Drive)
  0 to 20 dB
  Grid every 2 dB, labels every 4 dB (0, 4, 8, 12, 16, 20)

• Y‑axis (Adjustment)
  −1.0 to +1.0
  Grid every 0.2; zero line highlighted for reference
  Above zero = threshold boost (less limiting)
  Below zero = threshold reduction (more limiting)

Control points

The curve is defined by 6 points:

• Point 0 (Blue) — fixed at 0 dB Drive
  Vertically draggable (−1.0 to +1.0)

• Points 1–4 (Purple → Orange) — fully draggable
  Horizontal and vertical movement with left‑to‑right order preserved

• Point 5 (Blue) — fixed at 20 dB Drive
  Vertically draggable (−1.0 to +1.0)

Visuals:

• Endpoints = Blue (with vertical guide lines)
• Middle points = Purple → Dark Orchid → Orchid → Orange
• Clear outlines and hover feedback for precise edits

Workflow

1. Select the tab for the sidechain algorithm you’re using.
2. Set the toggle to USING UI to enable editing.
3. Drag points to shape the curve; audio updates in real time as you move them.
4. Switch tabs to tune curves for other algorithms as needed.
5. Save as part of your preset when you like the response.

Shaping guidelines

• Threshold boost (points above zero)
  Less limiting at that Drive region; useful for keeping openness at low/moderate Drive.

• Threshold reduction (points below zero)
  More limiting at that Drive region; useful for reining in high Drive without harshness.

• Keep curves smooth
  Avoid abrupt zig‑zags; smooth transitions produce more predictable musical results.

• Align with multiband goals
  Use the curve to complement L1 MULTIBAND METHOD and tone choices—e.g., let low Drive remain neutral, and only push harder as Drive approaches 12–20 dB.

Advanced techniques

• Drive‑dependent compensation
  If multiband reconstruction adds perceived loudness at certain Drive ranges, pull points slightly below zero there to keep loudness natural.

• Mode‑specific tuning

  • ARIA PASS1: Subtle curves work best—preserve transparency.
  • SIMPLE: Use a gentle S‑shape for musical glue.
  • STANDARD: Pair with Auto modes; keep the curve moderate to avoid fighting auto timing.
  • ENHANCED: Longer windows benefit from thoughtful shaping—avoid extremes, emphasize consistency.

• Handoff to Slot 2
  If you plan to use LIMITER SLOT 2, leave headroom—don’t push the curve too far negative at high Drive, so Slot 2 has space to work gracefully.

Visual feedback

• Color‑coded points for quick identification
• Live numeric values for each point while dragging
• Cursor change on hover to confirm what’s draggable

This panel gives you fine control over how Drive translates into limiting behavior in multiband. When the default math is close but not perfect for your program material, a few well‑placed points here can make the limiter feel effortless.

DATA Panel — Performance Monitoring

A real‑time health dashboard for Absolute Zero. Use it to spot bottlenecks, confirm stability, and diagnose issues quickly. The panel title appears as rotated text on the left: “OPTIMIZATION.”

Panel layout

Two clear columns:

• CPU Metrics (left)
• Audio Status (right)

CPU Metrics (left)

• CPU Load
  Current real‑time CPU usage.
  Color coding: Green (<50%), Orange (50–80%), Red (>80%).
  Updates ~10×/sec for responsiveness.

• Peak CPU
  Highest CPU usage since last reset.
  Use the reset button to baseline before tests.

• Avg CPU
  Running average for trend insight.
  Smooths out momentary spikes.

• Block Time
  Processing time per audio buffer (ms, 2‑decimal precision).
  Watch this relative to your DAW’s buffer duration.

• Buffer Usage
  Percentage of available audio buffer consumed.
  Helps identify when you’re approaching real‑time limits.

• Reset CPU Metrics
  Clears CPU statistics (Peak/Avg/etc.) to start fresh measurements.

Audio Status (right)

• Audio Status
  Overall indicator:

  • OK (Green): No issues detected
  • ISSUES DETECTED (Orange): Minor dropouts/spikes present
  • GLITCH DETECTED (Red): Serious overruns affecting audio

• Dropouts
  Count of brief interruptions in audio processing.
  White (0), Red (>0).

• Spikes
  Count of momentary CPU usage peaks.
  White (0), Red (>0).

• Overruns
  Count of critical processing overruns impacting audio.
  White (0), Red (>0).

• Reset Glitch Counters
  Clears dropout/spike/overrun counts to re‑baseline while troubleshooting.

INPUT Panel — Input Adaptive Gain

An intelligent pre‑conditioning stage that levels your input before it hits the limiter—so Drive lands in the sweet spot every time. Use the power toggle to enable/disable input leveling.

Panel structure

• Input Leveling Enabled (toggle) Master enable for the entire input‑adaptive system.
  Present for preview; leave OFF in production until the feature ships.

• Processing controls (rotary) Eight dials to tune the upcoming algorithm. Values are saved with presets.

Controls

• Block Size
  Analysis window for gain calculation (e.g., 16–4096 samples).
  Larger = steadier decisions; smaller = quicker reaction.

• Overlap
  Overlap between analysis windows (e.g., 16–2048×).
  Higher = smoother transitions, slightly more CPU.

• Peak Smoother
  Smoothing for peak detection (0.00–1.00).
  Higher = cleaner, less twitchy reaction to transients.

• RMS Smoother
  Smoothing for RMS detection (0.00–1.00).
  Higher = more stable loudness behavior.

• Limiter Release
  Recovery time for adaptive gain (e.g., 0.001–1.000 s).
  Faster = more transparent; slower = silkier but slower to settle.

• Max Gain
  Upper bound for automatic boost (e.g., 0.0–12.0 dB).
  Prevents over‑elevating quiet passages.

• Min Gain
  Lower bound for automatic attenuation (e.g., −12.0–0.0 dB).
  Prevents over‑reducing loud passages.

• Crest Comp
  Balances peak vs RMS influence (0.00–1.00).
  Higher = more transient‑aware; lower = more sustained‑level focus.

Development status

• Current state

  • UI and parameters are complete and saved with presets.
  • Real‑time parameter changes are visible in the UI.
  • Integration points to the main limiter chain are in place.

• What’s coming

  • Automatic level detection tuned to program content.
  • Intelligent, content‑aware input gain staging.
  • “Perfect Drive” estimation to land ideal limiter response.
  • Musical, content‑aware behavior that adapts during playback.
  • Real‑time optimization with robust safeguards.

Guidance for now:

• Keep the toggle OFF for critical work—treat this panel as a preview of the workflow.
• You can set and store your preferred parameters in presets today; behavior will activate in a future update without breaking your saved sessions.

TEST Panel — Limiting Verification and Analysis

Verify your limiting and inspect envelope behavior with a purpose‑built test harness. The TEST panel generates a controlled signal, runs it through your current chain, and visualizes the results with peak markers and an RMS envelope.

Panel structure

• Test controls (top)

  • TEST button
    Starts the verification run. Shows “TESTING” and disables while running; re‑enables on completion.
  • Channel Mode
    STEREO (both channels), LEFT (expanded left), RIGHT (expanded right).

• Waveform display (center) Dual, high‑resolution views with grid overlays:

  • Left channel: Purple/magenta waveform + white RMS envelope.
  • Right channel: Pink/magenta waveform + white RMS envelope.
  • Grids: Time (horizontal, ms) and amplitude (vertical, −1.0 to +1.0).

• Navigation (bottom)

  • Zoom
    1%–100% time‑axis zoom for macro ↔ micro inspection.
  • Pan
    Enabled when zoomed; scrolls the time window.

• Configuration and results (right or bottom, depending on layout)

  • Carrier Freq
    Test tone center frequency (20 Hz–20 kHz; default 4 kHz).
  • Peak Level Indicators (L/R)
    Post‑test peak readouts (dBFS, 0.1 dB precision).

Visual guides

• Peak markers (green)
  Absolute peak positions in the processed output.
• Pulse markers (orange)
  Start positions of injected test pulses.
• Envelope (white)
  RMS envelope overlay to visualize attack/release behavior.

Running a test

1. Set the desired Carrier Freq (default 4 kHz is a good general check).
2. Choose Channel Mode (STEREO for overview, LEFT/RIGHT for detail).
3. Click TEST. The button shows “TESTING” during capture and processing.
4. Review the waveforms, markers, and the L/R peak readouts when complete.
5. Adjust your chain (e.g., Slot 1, L1 MULTIBAND, Slot 2), and retest as needed.

Interpreting results

• Success criteria:

  • Peaks at or below 0 dBFS.
  • Envelope shows controlled, stable gain reduction.
  • Pulse (orange) and limiting response align logically in time.

• Potential issues:

  • Peaks > 0 dBFS
    Reduce Drive/output, increase lookahead, or adjust thresholds/knee.
  • Irregular/chattery envelope
    Increase smoothing, adjust attack/release, or consider STANDARD/ENHANCED behavior.
  • Misaligned markers vs response
    Revisit lookahead/latency settings; check for heavy upstream processing that shifts timing.

Navigation and inspection

• Macro overview (100% zoom)
  Quick confirmation of general behavior, overall peak safety.
• Micro inspection (<10% zoom)
  Sample‑level view of transient handling; study attack and recovery shape.
• Channel focus
  Use LEFT/RIGHT modes to isolate and compare channel behavior, particularly when Channel Link is low.

Practical tips

• Use a few representative Carrier Freq values (e.g., 1 kHz, 4 kHz, 8 kHz) to see how timing behaves across the spectrum.
• If the safety limiter (Column 5) frequently triggers in the test, reduce upstream output or refine Slot 2 timing/smoothing.
• For broadcast‑style consistency, try STANDARD in Slot 2 with modest Smooth and Auto Trans; confirm with micro inspection.
• When transparency is the goal, prioritize lookahead and gentle knees; verify that envelope transitions are smooth and peak markers sit at or below 0 dBFS.

This panel is your “trust but verify” step: it confirms that Absolute Zero’s limiting behaves exactly as intended before you print or ship.

Graphs & Views Reference

WAVEFORM GRAPHING VIEW

The waveform view gives you a live, zoomable picture of the limiter at work. Toggle which traces to show, zoom time and level to taste, pause to inspect a moment, and use the built‑in peak readouts to confirm headroom and limiting activity at a glance.

What you see

• Input: The raw signal arriving at the processor.
• Output: The post‑processing signal leaving the limiter chain.
• Gain Reduction: How much the limiter is pulling the signal down (around a 0 dB baseline).
• dB Grid: Fixed 2 dB lines and labels for quick level reading.

Core controls

• GRAPH: Master on/off for the display.
• INPUT / OUTPUT / GAIN REDUCTION: Show or hide each trace independently.
• RESET: Clear history and snap back to a sensible time window.
• Y‑AXIS (Range): Choose the vertical scale (tight detail down to broader views, ~−8 to −60 dB).
• Time Window: Horizontal zoom (0.5–60 s). Short for transients; long for envelopes/trends.
• PAUSE: Freeze the graph to inspect a moment without losing context.
• Position (Rewind): When paused, scrub back through recent history in seconds behind live.

Peak detection and readouts

• On‑trace callouts: Small dB labels appear near the right side for prominent peaks, pinned to the exact moment; they move with the scroll and fade as they exit.
• Peak summary table: A compact overlay beneath the graph showing:
  • Top 3 peaks in the current viewport (what you’re looking at now).
  • Top 3 peaks seen over the last second at the live edge (short‑term headroom).

How to work with it

• Understand the limiter: Enable OUTPUT + GAIN REDUCTION to see action vs result.
• Gain staging: Add INPUT to compare pre/post levels directly.
• Detail vs overview: Tighten Y‑AXIS and shorten Time Window for micro‑events; widen both for long‑form behavior.
• Investigate moments: PAUSE, scrub with Position, read the on‑trace peak labels and the 1‑second/viewport peak table to confirm exactly what happened.

Preset System — Libraries, Categories, and the Preset Panel

Absolute Zero’s preset system is modular and fast. You can capture the entire plugin state, or save targeted “subpresets” for specific modules like Limiter Slot 1, Limiter Slot 2, or a single column. The Preset Panel gives you a focused browser and one‑click workflow for loading, saving, resaving, and mirroring presets across limiter stages.

Note on Empty Preset Library (Early Build)

This build is brand new, so the Factory preset library may be empty. That’s expected. The app will still create the preset folders automatically, and you can start saving your own presets right away into the USER library. Factory packs will be added in upcoming updates.

• Preset path (macOS): ~/Music/altitude/product/ABSOLUTE_ZERO/preset/
• Libraries: FACTORY (read‑only, may be empty initially) and USER (your saves)
• Tip: Use SAVE to create Full State or subpresets; they appear immediately in the browser

Where presets live

Presets are stored on disk in a Factory/User library with a mirrored folder structure:

• macOS
  ~/Music/altitude/product/ABSOLUTE_ZERO/preset/
• Windows
  ProgramData/Altitude/product/ABSOLUTE_ZERO/preset/

Within preset/, two libraries exist:

• FACTORY/ — read‑only content shipped with the product.
• USER/ — your personal library. The app creates these folders on first run.

Top‑level categories (folders) mirror the system’s modules:

• FULL_STATE
• LAYOUT
• ARIA_PASS1_L1, ARIA_PASS1_L2
• SIMPLE_L1, SIMPLE_L2
• STANDARD_L1, STANDARD_L2
• ENHANCED_L1, ENHANCED_L2
• GLOBAL_COLUMN
• MULTIBAND_COLUMN
• SOFT_COLUMN (Output/Auto Output)
• SAFETY_COLUMN
• METER_CONTAINER
• DRIVE_REDUCTION

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Preset categories and scope

You can save either the entire system or targeted subsets:

• Full State
  • Captures the complete plugin state.
  • Excludes transient UI bits that shouldn’t be stored (e.g., certain view properties).
• Layout
  • Stores panel visibility/navigation state (e.g., which columns are on).
• Limiter Type subpresets
  • ARIA_PASS1_L1/L2, SIMPLE_L1/L2, STANDARD_L1/L2, ENHANCED_L1/L2
  • Each captures only the parameters for that limiter algorithm/stage.
• Column subpresets
  • GLOBAL_COLUMN, MULTIBAND_COLUMN, SOFT_COLUMN (Auto Output), SAFETY_COLUMN
  • Save column parameters only.
• Component subpresets
  • METER_CONTAINER, DRIVE_REDUCTION (curve editor settings)

Note:

• Some internal UI/control groups (e.g., waveform and window buttons) are included in Full State but not exposed as standalone preset categories.

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Preset Panel — Browser and Actions

A three‑pane browser with integrated filtering and file actions.

Layout:

• Left: ALL PRESETS — every category, grouped with headers.
• Right (top): LIMITER PASS 1 — L1 categories (ARIA/SIMPLE/STANDARD/ENHANCED + MULTIBAND column).
• Right (bottom): LIMITER PASS 2 — L2 categories (ARIA/SIMPLE/STANDARD/ENHANCED).

Controls:

• Search field with live filtering and a clear “X”.
• FILTER button — multi‑select category filter.
• Source filter — ALL / FACTORY / USER.
• Actions — LOAD, SAVE, RESAVE, DELETE, CLOSE.

Behavior:

• Double‑click a row to load it immediately (same as LOAD).
• Category header rows are not selectable.
• Factory presets can be loaded, but cannot be resaved or deleted.

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Loading presets

• Full State preset
  • Replaces the entire plugin state.
  • Good for swapping complete chains quickly.
• Subpreset (Limiter/Column/Component)
  • Applies only the parameters in that group, leaving everything else unaffected.
  • Great for auditioning limiter types, second‑stage variants, or column changes without losing your mix.

State sync:

• After loading, the panel updates the current preset name/category in the top bar.

Parameter Protection During Preset Loading

Absolute Zero includes a parameter protection system that prevents certain parameters from being overwritten when loading presets. This allows you to maintain specific settings while exploring different preset configurations.

Automatically Excluded Parameters

The following parameters are automatically excluded from preset loading to preserve session-specific settings:

• UI Layout Parameters — Panel visibility states, navigation settings, and interface configuration
• Language Settings — The current UI language selection is preserved across preset changes
• Window Management — Standalone visualization window positions and states

Lock Button System

Three lock buttons are available in the meter section to manually protect critical parameters:

• Input Lock — Protects the Input Gain parameter from preset changes
• Output Lock — Protects the Output Gain parameter from preset changes
• Drive Lock — Protects the Drive parameter from preset changes

Lock Button Operation:

• Located in the upper-left corner of each meter section (Input, Output, Drive)
• Locked State (Pink) — Parameter is protected and will not change during preset loading
• Unlocked State (White) — Parameter will be updated normally when loading presets
• Lock states are preserved when loading presets (lock buttons are never reset by presets)
• Tooltips display when hovering: "Lock [Parameter] during preset loading"

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Saving presets

Use SAVE to open the Save dialog:

• Choose the preset type (e.g., FULL_STATE, SIMPLE, STANDARD, GLOBAL_COLUMN, etc.).
• For limiter types, choose whether you’re saving for Limiter Slot 1 or Slot 2 (L1 vs L2). This means the parameter source you want saved--L1 or L2.
• Name and description are stored as metadata in the XML.

Destination:

• Saved to your USER/ library under the matching category folder.

Overwrite behavior:

• Full State presets prompt before overwriting.
• Synced limiter presets (see below) overwrite quietly as part of the paired write operation.

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Resaving and deleting

• RESAVE updates the selected User preset file in place.
  • Factory presets are protected; resave is blocked for Factory content.
• DELETE removes the selected User preset from disk (Factory content cannot be deleted).

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Dual‑Sync: Limiter 1 <> Limiter 2 (same algorithm)

When you save or resave any limiter‑type preset for L1 or L2, Absolute Zero automatically creates the paired preset for the other stage using a parameter mapper.

What it does:

• Copies the matching parameters across stages for the same algorithm family:
  • ARIA PASS1, SIMPLE, STANDARD, ENHANCED
• Translates parameter IDs from L1 format to L2 format (or vice versa) using a dedicated mapping:
• Handles L2‑specific behavior automatically:
  • Ensures the L2 stage is enabled in synced L2 presets.
  • For SIMPLE L2, adds the extra Threshold parameter (using a sensible default/current value).

Result:

• Saving a STANDARD L1 preset named “Glue 01” writes:
  • USER/STANDARD_L1/Glue 01.xml (primary)
  • USER/STANDARD_L2/Glue 01.xml (synced)
• Resaving one side updates the matching counterpart too.

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Reference: Categories and what they include

• FULL_STATE — Entire plugin state
• LAYOUT — Panel visibility/navigation
• ARIA_PASS1_L1 / ARIA_PASS1_L2 — ARIA Slot 1 / Slot 2
• SIMPLE_L1 / SIMPLE_L2 — Simple Slot 1 / Slot 2
• STANDARD_L1 / STANDARD_L2 — Standard Slot 1 / Slot 2
• ENHANCED_L1 / ENHANCED_L2 — Enhanced Slot 1 / Slot 2
• GLOBAL_COLUMN — Global detection/link/threshold and related controls
• MULTIBAND_COLUMN — L1 multiband/tone/reconstruction
• SOFT_COLUMN — Auto Output (soft safety stage)
• SAFETY_COLUMN — Final hard safety limiter
• METER_CONTAINER — Input/Output/Drive meters
• DRIVE_REDUCTION — Drive‑reduction curve editor settings

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VECTORSCOPE (LISSAJOUS)

The vectorscope plots Left vs Right as a 2D oscillogram, letting you see stereo width, correlation, and mono compatibility at a glance. Use it to quickly verify that your limiting hasn’t collapsed width or introduced phase issues.

What you see

• Left channel on the X‑axis; Right channel on the Y‑axis.
• Mono content collapses to a straight 45° line.
• Wider stereo appears as a diamond/ellipse.
• Out‑of‑phase content tends to rotate and cross the axes.

Core controls

• Style: Peak vs RMS path (fast vs averaged trajectory).
• Persistence/Averaging: Adjust trail length (short for transients; longer for overall behavior).
• Scale: Zoom the plot for your operating level.
• Channel Focus: Stereo (L/R), or isolate L or R for diagnosis.

How to work with it

• Center/phase check: A consistent 45° line = solid mono compatibility.
• Width sanity: Ellipse widens with intentional width; if it narrows unexpectedly, check Slot 2 timing and Channel Link.
• Problem hunting: Rotating or bow‑tie shapes often indicate phase issues upstream; confirm with Polar views.

POLAR SAMPLE

Polar Sample shows instantaneous samples in polar coordinates: angle = stereo position, radius = amplitude. It’s a high‑speed snapshot of how your content distributes across the stereo field moment to moment.

What you see

• Angle: 0° (Left) to 180° (Right).
• Radius: Instantaneous amplitude.
• Clusters: Reveal dominant panning positions and transient activity.

Core controls

• Mode: Standard vs Party (enhanced color mapping for density/energy).
• Peak vs RMS: Raw sample scatter vs averaged energy trend.
• Persistence: Tail length for cluster inspection.
• Scale: Radius scaling to keep the display readable at different levels.

How to work with it

• Transient localization: Short persistence + Peak mode to see where hits land spatially.
• Width auditing: Distribution should match your mix intent; overly center‑weighted clusters may suggest over‑linking or aggressive lookahead.
• Correlation triage: If clusters hover symmetrically but radius collapses, verify gain staging and GR behavior in the Waveform and Metering views.

POLAR LEVEL

Polar Level integrates energy over angle to show a stable stereo energy map. It’s the “average stereo picture” — useful for verifying width targets and long‑term balance post‑limiting.

What you see

• Angle: Pan position.
• Radius: Integrated energy at that position (averaged over time).
• In/Out distinction: Optional dual‑color to compare pre/post or correlate phase content.

Core controls

• Integration/Averaging: Controls stability vs responsiveness.
• Time Window: Short windows for mastering micro‑moves; longer for broadcast consistency.
• Display Mode: Stereo, or derived fields (Mid/Sides) if needed.
• Scale: Calibrate radius to current mix levels.

How to work with it

• Width target: Use medium averaging to confirm intentional width vs collapse.
• Phase hygiene: If energy skews oddly left/right over time, recheck balance and Channel Link.
• Consistency: For broadcast/podcast, aim for a stable, centered lobe with measured width, verified alongside the Metering panel.

FFT (SPECTRUM) VIEW

The FFT view provides real‑time frequency analysis with stereo and derived fields (L/R, Mid, Sides). Use it to confirm spectral balance before/after limiting and to catch unwanted resonances or harshness.

What you see

• X‑axis: Frequency (log scale).
• Y‑axis: Level (dB), with configurable range.
• Views: Stereo (overlaid L/R), Left, Right, Mid ((L+R)/2), Sides ((L−R)/2).

Core controls

• FFT Size: 1024–16k. Smaller = snappier; larger = more detail.
• Window Type: Choose analysis window (trade‑off leakage vs transient fidelity).
• Averaging: Temporal smoothing to steady the trace.
• Attack/Release: Visual ballistics; adjust for usable readings.
• Y‑Axis Range: Set amplitude span to keep detail visible.

How to work with it

• Tonal balance: Compare INPUT vs OUTPUT to confirm limiting didn’t tilt the spectrum.
• Sibilance/harshness: Watch 4–10 kHz during GR action; pair with Waveform peaks and GR meters.
• Mono compatibility: Mid/Sides comparison helps detect side‑heavy issues that fold poorly.
• CPU tips: If visuals lag, reduce FFT size or averaging.

WAVEFORM (POP‑OUT)

The pop‑out Waveform mirrors the main Waveform Graphing View in a detachable window for detailed inspection. Toggle traces, zoom time and level, pause, scrub, and use peak callouts to confirm headroom and limiting activity.

What you see

• Input, Output, and Gain Reduction traces with a fixed dB grid.
• On‑trace peak labels near the live edge.
• Optional peak summary table (top 3 in viewport and last second).

Core controls

• INPUT / OUTPUT / GAIN REDUCTION: Show/hide traces independently.
• Y‑AXIS (Range): Zoom vertical scale (~−8 to −60 dB).
• Time Window: 0.5–60 s horizontal zoom.
• PAUSE + Position (Rewind): Freeze and scrub back through recent history.
• RESET: Clear history and return to a sensible default window.

How to work with it

• Understand the limiter: OUTPUT + GAIN REDUCTION shows action vs result.
• Gain staging: Add INPUT to compare pre/post levels directly.
• Micro vs macro: Tighten Y‑AXIS and shorten Time Window for transients; widen both for envelope trends.
• Investigate moments: PAUSE, scrub, read on‑trace labels and the peak table.

METERING PANEL

The metering panel combines Input, Output, and Drive (Gain Reduction) meters with their respective controls for immediate, trustworthy level management.

What you see

• Input: Left/Right Peak and RMS in dB (fast peak, smooth RMS).
• Output: Left/Right Peak and RMS in dB (matched ballistics).
• Drive (Gain Reduction): Left/Right Peak and RMS reduction, referenced to 0 dB (0 = no reduction).

Core controls

• INPUT slider: Pre‑processing gain (linked to the “input” parameter).
• OUTPUT slider: Post‑processing gain (linked to the “output” parameter).
• DRIVE slider: Drive amount (linked to “drive”; controls how hard the limiter works).
• Visual ballistics: Fast peak + slower RMS for readable, musical metering.
• GR visuals: White numerics and top‑down fills for quick “more = more reduction” reading.

How to work with it

• Gain staging: Set INPUT to hit targets without over‑slamming Slot 1. Confirm with Waveform and GR meters.
• Makeup and level: Use OUTPUT to match bypass loudness or meet delivery specs.
• Drive control: Increase DRIVE while watching GR Peak/RMS; aim for consistent reduction without flat‑topping transients.
• Consistency check: If Output RMS drops while GR spikes erratically, revisit Slot 2 timing/smoothing; confirm via Waveform and FFT.

LOUDNESS METERS

The Loudness Meters window provides ITU-R BS.1770 compliant loudness measurement for broadcast, streaming, and professional delivery compliance. It displays both Input and Output loudness sections so you can monitor how the limiter affects program loudness.

What you see

• Two sections: Input (pre-processing) and Output (post-processing) loudness.
• Momentary (M): Loudness measured over a 400ms sliding window. Captures short-term loudness fluctuations and transient peaks.
• Short-term (S): Loudness measured over a 3-second sliding window. Shows medium-term loudness trends useful for mixing decisions.
• Integrated (I): Loudness measured over the entire program duration with gating. The primary measure for broadcast and streaming compliance (e.g., -14 LUFS for streaming, -24 LUFS for broadcast).
• LRA (Loudness Range): The difference between loud and quiet passages in LU (Loudness Units). Indicates dynamic range; typical targets are 5–20 LU depending on content type.
• True Peak (TP): Inter-sample peak level in dBTP measured using 4x oversampling per channel (L/R). Ensures no clipping occurs during D/A conversion. Broadcast standards typically require -1 to -2 dBTP maximum.
• Delta: The difference between Output and Input loudness (Output − Input). Positive values indicate increased loudness; negative values indicate reduction from limiting.

Audio/MIDI Settings (Standalone)

Absolute Zero Standalone uses the standard JUCE Audio/MIDI Settings panel to configure your audio interface and MIDI devices. These settings do not apply to the VST/AU plugin versions (plugins use the host’s audio/MIDI settings).

Where to find it

• Open the Audio/MIDI Settings panel from the app's menu or gear icon in the standalone application.

Audio device configuration

• Device Type / Driver
  • macOS: CoreAudio
  • Windows: WASAPI (Shared/Exclusive) or ASIO (if an ASIO driver is installed)
  • Select your input interface.
  • Enable/disable input channels (mono or stereo).
  • Optionally map channels if your interface exposes more than 2 inputs.
• Output Device
  • Select your output interface.
  • Enable/disable output channels (typically 1–2 for stereo).
• Sample Rate
  • Choose the operating rate (e.g., 44.1 kHz, 48 kHz, 96 kHz). For best stability, match the rate used by your OS or other apps.
• Buffer Size (Latency)
  • Smaller buffers reduce latency but increase CPU load and risk of dropouts.
  • Larger buffers improve stability at the cost of higher latency.
• Windows Exclusive Mode (WASAPI)
  • Exclusive: Absolute Zero gets full control of the device (lower latency, device locked to the app).
  • Shared: The device is shared with other apps (higher latency but more flexible).

MIDI device configuration (optional)

• MIDI Inputs
  • Enable any MIDI input devices you want Absolute Zero to listen to (if applicable to your workflow).
• MIDI Outputs
  • Enable any MIDI output devices if your setup requires sending MIDI from the app.

Tips and best practices

• Start with 48 kHz / 256–512 samples for a good balance of latency and stability.
• If you hear clicks/pops or see CPU overload warnings:
  • Increase the buffer size.
  • Close other audio apps.
  • On Windows, try WASAPI Exclusive or an ASIO driver if available.
• If there’s no sound:
  • Confirm the Output Device and channel selection.
  • Ensure the sample rate matches your system/interface.
  • Check that the device isn’t already in exclusive use by another app.
• Multi-interface setups (macOS):
  • Use the macOS “Audio MIDI Setup” utility to create an Aggregate Device if you need to combine multiple interfaces.

Persistence

• Your device, channel, sample rate, and buffer selections are remembered by the standalone app and restored on next launch.

Plugin note

• VST3/AU versions of Absolute Zero do not show this panel. The plugin uses the host’s audio engine and follows the host’s device, sample rate, and buffer size.

Technical Specifications

macOS

• Formats
  • VST3, AUv3, Standalone
• CPU/Architecture
  • Apple Silicon (arm64), Intel 64‑bit
• Operating System
  • macOS 10.15 Catalina or newer (Big Sur 11, Monterey 12, Ventura 13, Sonoma 14)
• Memory and Storage
  • Minimum 8 GB RAM (16 GB recommended)
  • 16 GB free disk space on system drive
• Display
  • Minimum: 1280×1024
  • Recommended: 1600×1024 or higher
• Audio/MIDI
  • CoreAudio; MIDI optional
• Plugin I/O
  • Stereo in, Stereo out (2‑in / 2‑out)
• Security/Runtime
  • Hardened Runtime enabled; AUv3 sandbox‑safe
• Notes
  • 64‑bit hosts only
  • AUv3 requires an AUv3‑compatible host

Windows

• Formats
  • VST3, Standalone
• CPU/Architecture
  • 64‑bit x86_64 (Intel or AMD)
• Operating System
  • Windows 10 (64‑bit), Windows 11
• Memory and Storage
  • Minimum 8 GB RAM (16 GB recommended)
  • 16 GB free disk space on system drive
• Display
  • Minimum: 1024×768
  • Recommended: 1280×1024 / 1600×1024 or higher
• Audio/MIDI
  • WASAPI (Shared/Exclusive) and ASIO (if installed); MIDI optional
• Plugin I/O
  • Stereo in, Stereo out (2‑in / 2‑out)
• Notes
  • 64‑bit hosts only

Sample Rates

• Both plugin and standalone support sample rates from 44.1 kHz up to 786 kHz (subject to device/host support).

Supported Hosts

• VST3: Most modern DAWs on macOS and Windows.
• AUv3: macOS hosts that support AUv3 (on macOS only).
• AAX: Not currently provided. But soon!