Air-G Echoes
User Manual
Version 1.0
Tape delay based on the Airwindows TapeDelay2 algorithm.
Original source code released under an open licence (MIT) by Chris Johnson.
User Manual
Version 1.0
Tape delay based on the Airwindows TapeDelay2 algorithm.
Original source code released under an open licence (MIT) by Chris Johnson.
Air-G Echoes is a tape delay: it repeats the signal the way an old tape echo would, with its warmth, its filtering and its unstable character. Under the hood it uses the Airwindows TapeDelay2 algorithm, created by Chris Johnson and released under an open licence.
What makes it special is that it is a «varispeed» delay (variable speed): the echo time is tied to the tape speed. So when you change the time while it plays, the tape speeds up or slows down and you hear that glissando (pitch slide) so characteristic of a real tape echo — not the clean, digital jump of other delays.
On top of Chris's foundation, Air-G Echoes adds four things: independent times for the left and right channels, a LINK button to tie them together, a SYNC button to lock the echo to the project tempo (in note values), and an HPF filter that cleans the low end out of the repeats.
Set the time with DELAY L/R (or lock it to tempo with SYNC), raise REGEN for more repeats, colour it with HPF / FREQ / RESO, and blend the echo with MIX. A touch of FLUTTER adds the living instability of tape.
Air-G Echoes interface.
The plugin is resizable (keeping its aspect ratio). Double-clicking a knob returns it to its default value.
Set the echo time of each channel independently. To the right the echo is longer; to the left it is shorter and faster. With SYNC off the value is shown in milliseconds; with SYNC on, in note values.
Because this is a tape delay, moving the time while it plays produces the glissando of the tape speeding up or slowing down — an intended effect, not a glitch.
Setting different times on L and R (with LINK off) creates stereo echoes and ping-pong effects.
Ties both channels to a single time: with LINK on, moving DELAY L or DELAY R moves the other to match, and both echoes stay equal. It is the classic even stereo delay. It is on by default. Turn it off when you want different times per channel (stereo / ping-pong).
Locks the echo to the project tempo. When enabled, the DELAY knobs stop showing milliseconds and instead select note values: 1/1, 1/2, 1/4, 1/8, 1/16, 1/32 — each in straight, dotted (D) and triplet (T) form. The echo always lands in time, and if you change the tempo, the echo time follows automatically.
DELAY L/R = time of each side (ms or note). · LINK = one shared time for both. · SYNC = to host tempo, in note values.
These three knobs shape the timbre of the repeats. The key thing: they act inside the echo loop, so their effect accumulates — each repeat passes through the filter again and gets more coloured than the last, just like real tape.
A high-pass filter that removes the lows from the repeats. As you raise it, each echo loses more low-end body than the previous one, so the delay tail gradually clears up and thins out — the classic trick to keep many repeats from turning into mud. Fully left it is OFF.
Controls the brightness of the echo. Up, the repeats sound clear and bright; down, dark and dull, like an old slapback. Combined with HPF it lets you frame the exact tone of the echo (HPF cleans the lows, FREQ handles the highs).
Adds resonance (an emphasis) right at the FREQ point. Raising it makes the filter «sing» at that frequency and the echoes become more coloured, narrow and resonant — perfect for pronounced dub sounds. At zero the tone is neutral and open.
Per Chris, this filter is a very wide band-pass: that is why, even in its most «open» position, the echo keeps an analogue character and never sounds fully digital.
Adds the living instability of tape (wow & flutter): a slight wavering and undulation in the pitch of the echoes. At low values it gives a subtle, realistic movement, like a well-kept tape machine; pushed high, the echo turns wobbly and weird, great for creative effects. It is most noticeable with several repeats (REGEN up).
The feedback: how many times the echo repeats. At minimum you hear a single repeat; as you raise it the repeats chain together and last longer, up to very long, near-infinite tails. With REGEN high, the tone controls (HPF/FREQ/RESO) and FLUTTER become very prominent, because their effect accumulates on every pass.
Blends between the dry signal (no effect) and the echo. Raising MIX puts more echo in the mix. It is designed to add the echo without turning down the original signal, so you can place it on a channel or a bus and dial in how much echo you add without upsetting the rest of the balance.
You can also use it on a send/return channel with MIX at maximum, as a separate delay.
The reel in the upper window spins in time with the DAW transport: it turns while the project plays and stops when you stop. A click on it pauses or resumes the animation, in case you prefer to leave it still. It is purely visual: it does not affect the sound.
The panel lights up softly when the plugin is processing audio, and dims when signal stops passing through. It is a visual cue that the effect is active and working.
Under the hood, Air-G Echoes runs the «tape» always at the same internal resolution and makes it spin faster or slower depending on the time you choose. That is why changing the time sounds like speeding up or slowing down a real tape (with its glissando), and why FLUTTER and time changes have that particular organic flavour.
Short time, low REGEN (one or two repeats), FREQ down for a dark, vintage echo. Adds depth without muddying the vocal.
High REGEN, HPF up and FREQ down with RESO up: long, dark, resonant tails. Add FLUTTER to make it «breathe».
Turn LINK off and set different times on DELAY L and DELAY R (for example 1/8 and 1/4 with SYNC): the echoes bounce between the two sides and widen the image.
Enable SYNC and pick a note value (1/4, dotted 1/8, etc.): the echo always stays in tempo, even if you change the project BPM.
For an echo that doesn't cover the mix: raise HPF to remove the lows and lower FREQ a little to darken the repeats. That way the delay is felt without fighting the main signal.
Air-G Echoes was developed by Air-G Audio as part of the line of plugins based on the work of Airwindows.
The TapeDelay2 algorithm is the work of Chris Johnson (Airwindows), whose original source code is released under an open licence (MIT). Air-G Echoes is a reimplementation of the original algorithm with its own additions: independent L/R times, LINK, tempo sync (SYNC, in note values) and an HPF filter in the feedback.
To Chris Johnson, for his tireless work at Airwindows and for sharing decades of audio-processing research completely openly.
Air-G Echoes v1.0 — Air-G Audio. The TapeDelay2 algorithm is the work of Chris Johnson / Airwindows and is used under the terms of his open licence (MIT).