Air-G Logo

Air-G Tape

User Manual

Version 1.0

Based on the work of Chris Johnson — Airwindows.
Source code published under open license.

Table of Contents

1 — What is Air-G Tape?2
2 — User Interface3
Reels4
Tape Head — Head Bump / Head Freq4
Flutter / Flt Speed5
EQ — Low / Mid / High5
Tonal Controls6
Gain Staging7
VU Meter7
3 — Special Modes8
4 — Usage Tips & Presets8
5 — Credits & Acknowledgements9

What is Air-G Tape?

Air-G Tape is an analog tape emulation based on the ToTape9 engine by Airwindows. Its purpose is to transform audio the way real tape does: adding density, natural compression, high-end smoothness, and a cohesion that makes tracks, buses, or mixes sound larger and less digital.

The processing includes harmonic saturation, low-end reinforcement (head bump), subtle wow/flutter speed variations, and a three-band equalizer applied post-tape. Two stereo image modes —Crosstalk and Stereo Width— allow adjusting the stereo field independently from the rest of the processing.

The result can be used in an almost invisible way —to add glue and air to a bus— or more pronounced to color drums, bass, guitars, or the full master. The depth of the controls allows you to find the exact point between transparency and character.

User Interface — Control Map

Air-G Tape UI
1
Reels — Animated tape reels. Click to pause/resume.
Logo — Click to collapse / expand the reels panel. It lights up on hover.
2
Tape Indicator — LED active while tape is running.
3
Tape Head — Magnetic head simulation.
4
Head Bump — Low-end emphasis/body.
5
Head Freq — Bump resonance frequency.
6
Flutter — Amount of wow/flutter variation.
7
Flt Speed — Flutter effect speed.
8
EQ Low / Mid / High — 3-band post-tape equalizer.
9
Dobly — Tonal character: presence vs. darkness.
10
Tape Bias — Hardness of the transition to saturation.
11
Tape Shape — Personality: vintage vs. modern.
12
ST/CT — Crosstalk (orange) / Stereo Width (green).
13
Input Gain — Input level to the tape.
14
Volume — Overall output level.
15
Clip Level — Saturation/clipping threshold.
16
Menu / Options — Presets and settings.
17
VU Meter — Post-processing level meter.

Mechanical Controls

1 Reels

The reels are the visual representation of the tape spools. They animate when the tape engine is active, spinning in sync with the processing.

Interaction: clicking on either reel stops the animation and pauses the visual movement of the reels. A second click resumes them. This function does not affect audio processing —it is a visual preference.

Collapsing the panel: a click on the logo (on the head, between the reels) hides the top strip with the reels to save screen space; a second click shows it again. The logo lights up on hover to show it is clickable, and the transition is animated. (This is purely visual: it does not affect the audio.)

Reels — detail

Reels — detail

2 Tape Indicator — LED

The small LED located between the reels lights up when the tape engine is active. It remains off when the plugin is in bypass or inactive.


3–5 Tape Head — Head Bump / Head Freq

Head Bump (control ④)

Head Bump models the "punch" of the head on the tape: the way the magnetic head gives the low end more impact and body, rather than leaving it flat or transparent.

  • More Head Bump: greater perceived low-end energy, more "glue". The tape feels more cohesive; bass and kick drum are glued into the mix.
  • Less Head Bump: the audio becomes flatter, with more controlled low end.
  • Interaction with drive: pushing this area enters non-linear behavior faster.

Head Freq (control ⑤)

Determines where in the low end the bump is felt; shifts the impact point toward sub-bass or toward the low-mids.

  • Low Head Freq: the bump sits lower (sub-bass / foundation).
  • High Head Freq: the bump moves upward (more presence in the low-mids).

Workflow: first set Head Bump to define the amount; then use Head Freq to place that energy exactly where you want it.

Tape head sectionHead section


6–7 Flutter / Flt Speed

Flutter (control ⑥)

Flutter introduces the wow/flutter modulation of the transport: small speed variations that make the tape processing less than 100% stable over time. This happens because in a real machine the motor and mechanical system cause the tape to advance slightly irregularly, generating micro-variations of pitch and timing. The flutter combines a slow wow with a faster flutter plus a gentle drift, mirroring how a real tape machine fluctuates at several rates at once.

  • It brings life and movement to the audio, removing it from digital rigidity.
  • The more Flutter, the more pronounced the variation. Taken to the extreme, it creates creative degradation: the exaggerated instability deliberately sought to add character or effect.
  • Works best once you have Input/Clip Level set to the desired point.

Flt Speed — Flutter Speed (control ⑦)

Adjusts the pace of the wow/flutter: controls how quickly the modulation moves the transport. Low values = slow, expressive wow; high values = fast, vibrant flutter.

Flutter section

Flutter section

EQ & Tonal Controls

8 EQ — Low / Mid / High

Based on Airwindows' SmoothEQ3, this section is a three-band equalizer designed to be extremely efficient and high quality. It is applied to the signal after tape processing.

  • Steeper filtering: unlike a standard Butterworth filter, SmoothEQ3 combines a simple IIR with an additional layer for a steeper slope, allowing focus on lows or highs without unnecessarily affecting the mids.
  • Transient optimization: the design seeks a balance so the sound remains natural and transients stay clear.
  • Extreme efficiency: uses only 59 operations per sample per channel, making it suitable for very dense mix configurations even on limited hardware.
3-band EQ

3-band EQ


Tonal Controls

9 Dobly

Dobly works as a tonal tilt control: it tilts the tape's response toward a brighter or darker sound, similar to the calibration adjustments made on real analog tape machines.

Typical use: once the desired saturation has been set with Input/Clip Level, Dobly defines the final tonal character: upward, the tape sounds brighter and more present; downward, more compact, dark, and dense.

10 Tape Bias

Tape Bias adjusts the operating point of the tape: it affects the frequency response and harmonic distortion, and defines the hardness of the transition into the non-linear range when the signal approaches the limit.

  • Toward 0: more punch/character, greater tonal coloration, more pronounced transition.
  • Toward 100: more smoothness and control, more neutral response, more gradual transition.

11 Tape Shape

Global tape character control: defines whether the sound is more classic and defined, or more relaxed and deep —the kind of tone associated with large recording studios.

  • Toward 0: more direct and defined, with saturation more "punch-oriented". The character is felt from the input stage.
  • Toward 100: more relaxed, rounded, and deep. The transformation occurs in the final stage, with a more consistent and blended behavior.
Tonal controls panel

Tonal controls panel


12 Stereo Width / Crosstalk — ST/CT Button

The ST/CT button toggles between two stereo image modes with each click. The button LED indicates which is active:

Crosstalk (orange LED) — simulates inter-channel crosstalk, adding cohesion and analog character. Changes the stereo type to sound more "tape/machine-like" and generally preserves the center better in mono.
Stereo Width (green LED) — activates advanced stereo widening. Widens the stereo perception by "opening up" the sides. To prevent the low end from falling apart in mono, the plugin reduces the side contribution at low frequencies when widening the stereo, keeping the center more stable.

Gain Staging

13 Input Gain

Input Gain defines how much "drive" you give the tape. By pushing the signal harder, the algorithm saturates more, adding natural compression and harmonic coloration. It is the main control for managing the amount of effect.

14 Volume

Volume controls the overall output level of the plugin. Its main use is as a comparison make-up: adjust it so the result stays at the same perceived level as the unprocessed signal while you change the character. It does not affect tape processing.

The small red LED above the Volume knob is the real clip indicator (with persistence). When it lights up, it indicates that the signal is clipping at the output.

15 Clip Level

Clip Level controls how much signal is sent to the final clipper, and its behavior is dual:

  • Higher: you hit the clipping stage harder, which acts as a volume maximizer and adds aggressive presence.
  • Lower: you reduce that output distortion and focus on the pure character of the tape algorithm, without the clipper's effect.

The recommended starting point is 50%, which offers a balance between the two behaviors.

Airwindows' classic strategy applies dither/noise around the final stage and in the clipping area to prevent artifacts from sounding like "hard aliasing". The result integrates as texture within the character.

Quick Gain Staging Rule

  • For cleaner sounds: lower Input Gain and/or Clip Level.
  • For more character: push to the desired point, then use Volume to match the perceived level.
Input Gain · Volume · Clip Level

Input Gain · Volume · Clip Level


VU Meter

17 VU Meter

The VU Meter is not a literal reading of the audio output but a "visual" reading mapped to tape-like behavior. It helps you locate energy and find the balance between character and control.

How to read the scale:

  • For less saturation: keep the VU away from the red zone and reduce Input/Clip Level.
  • For more character: push the level into the red zone. The VU meter's red zone does not imply signal clipping but rather the presence of more harmonic character. The real clip indicator is always the small red LED above the Volume control.

This intentional behavior allows using the VU as an expressive guide —not a peak meter— to work the tape drive musically.

VU Meter

VU Meter

Special Modes

Crosstalk Mode (orange LED)

Analog cohesion, tape character, better mono compatibility. See control ⑫ section for full description.

Orange LED = active.

Stereo Width Mode (green LED)

Advanced stereo widening with low-end control in mono. See control ⑫ section for full description.

Green LED = active.

ST/CT button: toggles between Crosstalk and Stereo Width with each click.


Presets

Button 16 opens the factory presets menu. Air-G Tape includes 48 presets organized in categories:

Mix & Master

  • Airwindows — ToTape9 base configuration; neutral starting point.
  • Just Tape Glue — minimal coloration, maximum glue. For buses.
  • Subtle Bus Glue — nearly invisible glue, no coloration. For master.
  • Clean and Open — subtle character with wide stereo image.
  • Sweet Spot — balance between character and transparency.
  • Modern — controlled saturation with flat response.
  • Chrome — chrome tape type: more brightness, less body.
  • Vintage — vintage tape with soft compression and low-end body.
  • Warm — emphasis on warmth and density.
  • Old Cassette — strong coloration in analog cassette style.
  • Broken Tape — exaggerated flutter and intentional degradation.
  • Lo-Fi Push — high drive, flutter, dark tone. Lo-fi character.

By Instrument

  • Drums — Vintage Punch, Modern Glue, Modern Tight, Room Feel, Hard Hit
  • Electric Guitar — Thick Tube, Wide Chorus, Crunch Vintage, Lead Bite, Clean Shimmer, Tape Chorus
  • Acoustic Guitar — Natural Room, Gentle Spread, Warm Intimate, Open Stage, Vintage Folk
  • Bass — Tight Note, Sub Glue, Vintage Round, Aggressive Drive, Warm Upright
  • Keys — Soft Pad Tape, Cinematic Spread, Bright Sustain, Rhodes Warm, Vintage EP
  • Pads — Wide Wash, Dream Glue, Vintage Nebula, Ethereal Drift, Dark Ambient
  • Vocals — Clean Air, Bus Warm, Presence (vocal bus)  ·  Lo-Fi Tape, Phantom (FX)

Presets that use Crosstalk or Stereo Width activate the mode automatically when selected. Current settings are saved with the DAW session (auto-recall).


Usage Tips

Recommended Workflow

  1. Set Input Gain to achieve the desired level on the VU Meter.
  2. Use Clip Level to add more or less saturation.
  3. Experiment with Tape Bias and Tape Shape to find the ideal character.
  4. Activate Crosstalk for more vintage cohesion.
  5. Activate Stereo Width for a wider stereo image.
  6. Adjust Volume to match the perceived level for A/B comparison.

Typical Use Cases

  • Subtle use (glue): low Input Gain, Clip Level at 50%, moderate Head Bump. Ideal for buses and master.
  • Aggressive coloring: high Input Gain, low Clip Level, Tape Bias toward 0. Ideal for drums and synthesizers.
  • Vintage character: Flutter active, high Dobly, Crosstalk activated.
  • Low-end control: Head Bump at 60-70%, Head Freq according to the material type.

Visual Indicators — Quick Reference

Credits & Acknowledgements

The sonic core of this project is inspired by the work of Chris Johnson of Airwindows, with components drawn from his public code. The saturation and tape emulation engine of Air-G Tape is based on ToTape9, which I consider one of the best tape emulators available. I went a step further trying to make it just a little better.

A user interface was added that, in addition to incorporating useful features (3-band EQ based on SmoothEQ3, Crosstalk, advanced Stereo Width, VU meter), aims to make the experience more pleasant and visual. The result is a sonic behavior very close to the code it is based on, but with extra tools to shape and work the audio with more intuitive visual elements.

All of this with the commitment to maintaining the simple, lightweight, and free philosophy that runs through all of Chris's work.

Airwindows Components Used

Special Thanks

To Juani and Tomi for their ever-present collaboration. Thank you!

* This project draws its sonic foundation and ideas from Airwindows. Thanks to Chris Johnson of Airwindows for his work and for making his code public.

MIT License — Airwindows

Copyright (c) 2018 Chris Johnson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

VERSION 1.0