THE INVERTER CYCLE

Audio Production Specifications

Technical Standards & Creative Guidelines

Version: 1.0
Date: March 13, 2026
Applies to: All three audiobooks (WILDFLOWER, TALLY, COGITO)

TECHNICAL SPECIFICATIONS

Recording Standards

Parameter	Specification	Notes
Sample Rate	48 kHz	Broadcast standard for recording
Bit Depth	24-bit	Headroom for editing
Format (Recording)	WAV	Uncompressed, archival quality
Format (Delivery)	MP3	Compressed for distribution
Sample Rate (Delivery)	44.1 kHz	CD standard
Bit Rate (Delivery)	192 kbps	Audible minimum
Channels	Mono or Stereo	Narrator preference

Platform-Specific Requirements

Audible (ACX) - PRIMARY PLATFORM

File Format: MP3
Bit Rate: 192 kbps or higher
Sample Rate: 44.1 kHz
Channels: Mono or Stereo

Audio Levels:
- RMS: -20dB to -23dB (average)
- Peak: -3dB maximum (no clipping)
- Noise Floor: -60dB or lower (silent sections)

File Naming: [ISBN]_[BookTitle]_[Chapter].mp3

Spotify

File Format: MP3 or WAV
Bit Rate: 192 kbps minimum
Sample Rate: 44.1 kHz

Additional: 
- Chapter markers embedded
- Metadata complete (see below)

Apple Books

File Format: M4B (AAC) or MP3
Bit Rate: 128-256 kbps
Sample Rate: 44.1 kHz or 48 kHz

Additional:
- Supports enhanced audio (images, links)
- Chapter artwork possible

Library Platforms (OverDrive, hoopla)

File Format: MP3
Bit Rate: 256-320 kbps (higher quality preferred)
Sample Rate: 44.1 kHz

Note: Libraries often prefer higher quality

CHAPTER STRUCTURE

File Breakdown

Each book should be delivered as:

Individual chapter files (preferred by platforms)
OR single file with embedded chapters (M4B)

Recommended Structure:

WILDFLOWER_Audiobook/
├── 01_Opening_Credits.mp3
├── 02_Dedication.mp3
├── 03_Epigraph.mp3
├── 04_Preface.mp3
├── 05_Chapter_01.mp3
├── 06_Chapter_02.mp3
├── ...
├── 14_Chapter_09.mp3
├── 15_Acknowledgments.mp3
└── 16_Closing_Credits.mp3

Chapter Length Guidelines

Book	Chapters	Est. Runtime/Chapter	Total Runtime
WILDFLOWER	9	20-25 min	~3.5 hours
TALLY	8	18-22 min	~2.7 hours
COGITO	8	18-22 min	~2.6 hours

Note: Chapters should not exceed 120 minutes (platform limit).

METADATA SPECIFICATIONS

ID3 Tags (MP3)

Every file must include:

Title: Chapter X: [Chapter Title] / [Book Title]
Artist: [Narrator Name]
Album: The Inverter Cycle: [Book Title]
Album Artist: [Author Name]
Year: 2026
Genre: Audiobook / Science Fiction
Track Number: X
Comment: [Brief description]
Composer: [Author Name]
Publisher: [Publisher Name]
ISBN: [ISBN-13]

Example (WILDFLOWER Chapter 1):

Title: Chapter 1: The Discovery / WILDFLOWER
Artist: [Narrator Name]
Album: The Inverter Cycle: WILDFLOWER
Album Artist: [Author Name]
Year: 2026
Genre: Audiobook
Track Number: 5
Comment: Helena Voss makes a breakthrough in quantum biology that will change everything.
ISBN: 978-XXX-XXXXXX-X

AUDIO QUALITY STANDARDS

Recording Environment

Room Requirements:

Reverb time (RT60): < 0.5 seconds (dead room)
Background noise: < -60dB
No audible HVAC, traffic, or electronics
Isolation from external sounds

Microphone Technique:

Distance: 6-12 inches from mic
Pop filter: Mandatory
Angle: Slight off-axis to reduce plosives
Consistent positioning throughout

Editing Standards

What to Remove:

Mouth clicks (de-click plugin)
Heavy breaths (reduce, don’t eliminate)
Room tone inconsistencies
Page turns (if using paper)
Long pauses (>3 seconds, unless dramatic)

What to Keep:

Natural breaths (humanizes narration)
Character-appropriate pauses
Performance energy
Authentic page turns (if in character)

Transitions:

Crossfade: 10-20ms between edits
Room tone: Match levels carefully
No audible edit points

Mastering Chain

Recommended Processing:

EQ (subtle)
- High-pass: 80 Hz (remove rumble)
- Low shelf: +1-2dB at 100-200 Hz (warmth)
- Presence: +1-2dB at 3-5 kHz (clarity)
- Air: +1dB at 10+ kHz (if needed)
Compression (gentle)
- Ratio: 3:1 to 4:1
- Threshold: -20dB to -24dB
- Attack: 5-10ms
- Release: 50-100ms
- Gain reduction: 3-6dB maximum
Limiter (safety)
- Ceiling: -3dB (prevent clipping)
- Threshold: -6dB to -9dB
- Release: Auto or 50ms
Normalization
- Target: -20dB RMS (ACX standard)
- True peak: -3dB maximum

THE 77 Hz AUDIO QUESTION

The Creative Dilemma

The trilogy features a 77 Hz frequency that unifies the story:

Scientific: Quantum coherence frequency
Mechanical: Bus engine harmonic (TALLY)
Tidal: Ocean resonance (COGITO)

Question: Should the audiobook incorporate this frequency?

Options Analysis

Option 1: No 77 Hz (RECOMMENDED)

Implementation:

No sub-bass frequency added
Focus on clean narration
Mention 77 Hz in liner notes only

Pros:

Cleanest audio experience
No speaker distortion risk
No listener fatigue
Widest compatibility

Cons:

Misses potential immersive element

Verdict: SAFEST CHOICE

Option 2: Chapter Transition Tones

Implementation:

77 Hz sine wave at chapter breaks only
Duration: 2-3 seconds
Level: -40dB (barely audible)
Fade in/out: Smooth curves

Pros:

Sonic signature for the series
Doesn’t interfere with narration
Creates subconscious continuity

Cons:

May be perceived as “hum” or audio problem
Requires careful level matching

Technical Requirements:

Frequency: 77.0 Hz
Waveform: Sine
Duration: 2-3 seconds
Level: -40dB to -45dB
Fade: 500ms in, 500ms out

Option 3: Subliminal Bed (NOT RECOMMENDED)

Implementation:

77 Hz tone throughout entire audiobook
Level: -50dB or lower
“Felt” more than heard

Pros:

Thematic unity
Experimental audio

Cons:

Speaker distortion (small speakers can’t reproduce)
Listener fatigue over 3+ hours
Potential health concerns (exposure to low frequencies)
ACX may reject (noise floor issues)

Verdict: TOO RISKY

FINAL RECOMMENDATION

Use Option 1 (No 77 Hz) for audiobooks.

Reasoning:

Audiobooks prioritize clarity and comprehension
77 Hz works brilliantly in screenplays (sound design)
Less effective in audiobook format
Risk of technical/health issues

Alternative:

Include 77 Hz in marketing materials (trailers)
Mention in liner notes as “easter egg” for readers
Focus on excellent narration quality instead

MULTI-PERSPECTIVE AUDIO TREATMENT

Each chapter has five perspectives. Consider subtle audio differentiation:

Option A: No Treatment (RECOMMENDED)

Rely on narrator’s voice acting
Cleanest, most professional
No effects to distract

Option B: Subtle Treatments

THE PLAY (Screenplay):

Slight “presence” boost (+1dB at 5kHz)
Most “forward” sounding

Character Interior (Journal):

Slight warmth (+1dB at 200Hz)
Most intimate

Institutional (Reports):

Slight thinness (high-pass at 120Hz)
More “paper” quality

Frame (Nick):

Slight distance (small room reverb)
Memory quality

The Network:

Slight modulation (chorus effect, 5% wet)
Otherworldly but subtle

WARNING: Use EXTREME subtlety if implementing. Effects should be barely perceptible.

QUALITY CONTROL CHECKLIST

Before Submitting Each File

Technical:

File format correct (MP3, 192kbps, 44.1kHz)
RMS level: -20dB to -23dB
Peak level: -3dB maximum
Noise floor: -60dB or lower
No audible edits or clicks
Consistent volume throughout

Performance:

Metadata:

ID3 tags complete
Chapter titles accurate
ISBN included
Cover art embedded (if supported)

Content:

Opening credits present
All chapters included
Closing credits present
No missing sections

DELIVERY SPECIFICATIONS

File Naming Convention

[ISBN]_[BookTitle]_[ChapterNumber]_[ChapterTitle].mp3

Example:
9780123456789_WILDFLOWER_01_TheDiscovery.mp3

Folder Structure

TheInverterCycle_Audiobooks/
├── WILDFLOWER/
│   ├── 01_Opening_Credits.mp3
│   ├── 02_Chapter_01_TheDiscovery.mp3
│   ├── ...
│   ├── cover.jpg (2400×2400px)
│   └── metadata.xml
├── TALLY/
│   ├── 01_Opening_Credits.mp3
│   ├── ...
│   ├── cover.jpg
│   └── metadata.xml
├── COGITO/
│   ├── 01_Opening_Credits.mp3
│   ├── ...
│   ├── cover.jpg
│   └── metadata.xml
└── README.txt

Cover Art Specifications

Platform	Dimensions	Format	Color Space
Audible	2400×2400px	JPG	RGB
Apple	1400×1400px min	JPG	RGB
Spotify	3000×3000px	JPG	RGB
Recommended	3000×3000px	JPG	RGB

File size: Under 5MB per image

REVISION POLICY

What Constitutes a Revision

Minor (can be patched):

Single mispronunciation
Small edit fix
Metadata correction

Major (requires re-recording):

Significant misread
Inconsistent character voice
Technical quality issue

Revision Workflow

Note timestamp of issue
Record corrected section (with room tone)
Edit into original file
Re-master affected section
Re-check levels
Re-deliver file

PLATFORM-SPECIFIC NOTES

Audible (ACX) Quality Check

ACX has strict standards. Common rejection reasons:

Issue	Cause	Solution
RMS too high	Too loud	Lower gain, re-compress
RMS too low	Too quiet	Raise gain, less compression
Peak too high	Clipping	Lower limiter threshold
Noise floor too high	Background noise	Better isolation, noise reduction
Inconsistent levels	Performance variance	Better compression, leveling

ACX Check Tool: Use ACX Check plugin (Audacity) or similar before submission.

Spotify for Audiobooks

Growing platform for audiobooks
Less strict than ACX on technicals
Focus on metadata completeness
Chapter markers important

Library Distribution

Higher quality often expected
Consider 256-320 kbps for libraries
MARC records may be required
Processing time: 4-8 weeks

BACKUP & ARCHIVAL

Master Files

Keep uncompressed masters:

Format: WAV, 48kHz/24-bit
Storage: Cloud + local backup
Retention: Permanent

Session Files

If using DAW:

Save session files with audio
Document settings used
Keep for future revisions

Delivery Files

Keep final delivered MP3s:

Exactly what was submitted
For reference/comparison
For re-distribution if needed

FINAL CHECKLIST

Before declaring audiobook complete:

Technical:

All files meet platform specifications
Quality check passed (ACX or equivalent)
Metadata complete on all files
Cover art correct dimensions

Creative:

Narrator guide followed
Character voices consistent
Pronunciations verified
77 Hz decision implemented (or not)

Production:

Masters archived
Delivery files organized
Documentation complete
Rights clearances obtained

Distribution:

Platform accounts set up
Files uploaded
Descriptions written
Marketing materials ready

CONTACTS

Technical Questions: Audio engineer/producer
Creative Questions: Author/narrator
Platform Issues: Platform support (ACX, Spotify, etc.)
Rights Questions: Publisher/legal

Specifications subject to platform updates. Verify current requirements before final delivery.

END OF SPECIFICATIONS

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Explorer

AUDIO_SPECIFICATIONS

THE INVERTER CYCLE

Audio Production Specifications

Technical Standards & Creative Guidelines

TECHNICAL SPECIFICATIONS

Recording Standards

Platform-Specific Requirements

Audible (ACX) - PRIMARY PLATFORM

Spotify

Apple Books

Library Platforms (OverDrive, hoopla)

CHAPTER STRUCTURE

File Breakdown

Chapter Length Guidelines

METADATA SPECIFICATIONS

ID3 Tags (MP3)

Example (WILDFLOWER Chapter 1):

AUDIO QUALITY STANDARDS

Recording Environment

Editing Standards

Mastering Chain

THE 77 Hz AUDIO QUESTION

The Creative Dilemma

Options Analysis

Option 1: No 77 Hz (RECOMMENDED)

Option 2: Chapter Transition Tones

Option 3: Subliminal Bed (NOT RECOMMENDED)

FINAL RECOMMENDATION

MULTI-PERSPECTIVE AUDIO TREATMENT

Option A: No Treatment (RECOMMENDED)

Option B: Subtle Treatments

QUALITY CONTROL CHECKLIST

Before Submitting Each File

DELIVERY SPECIFICATIONS

File Naming Convention

Folder Structure

Cover Art Specifications

REVISION POLICY

What Constitutes a Revision

Revision Workflow

PLATFORM-SPECIFIC NOTES

Audible (ACX) Quality Check

Spotify for Audiobooks

Library Distribution

BACKUP & ARCHIVAL

Master Files

Session Files

Delivery Files

FINAL CHECKLIST

CONTACTS

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