Doobie

The tape is a single loop, and four playback heads sit along it. Each has its own level, its own pan, its own time, and a nudge of up to two hundred milliseconds either side for the kind of micro-timing that opens a stereo image without touching a width control.

In sync each head snaps to a musical division, so the taps land on the grid; free-running they sit at any continuous fraction of the repeat. A four-pad matrix switches heads in and out while it plays, and switching is silent — heads ramp rather than cut, so you can rearrange the rhythm live without a click.

Times run from twenty milliseconds to eight seconds free, or from a sixty-fourth up to four bars locked to the host, dotted and triplet included. The buffer goes out to sixteen seconds, so a slow ambient drone fits with room to spare. Change the division while it is running and the pitch glides like a capstan spinning up, because that is what a capstan does.

Digital keeps the repeat clean. Tape adds wow, flutter and saturation. BBD is the dark, narrowing bucket-brigade sound, losing top end every time round. Diffuse smears the repeats into a wash rather than a rhythm. And Pitch moves every repeat by an interval you choose.

Over the top of all of that sits AGE, which wears the tape down: hiss, slow level dropouts, progressive high-frequency loss and extra transport instability, compounding a little more on every pass. Turn it up and the twelfth repeat is a different creature from the first.

The Pitch character is not a fixed octave trick. The interval is a chip row running from twenty-four semitones down to twenty-four semitones up, so the repeats can climb into shimmer, fall into a sub-octave drone, or move by a fifth and turn a single note into a chord that builds itself as it decays.

It has its own on-off switch, separate from the character selector. That sounds like a small thing and it is the control I use most: it lets you A and B the shifter against itself without changing the delay character underneath, so you can hear exactly what the interval is doing rather than what switching modes is doing.

Both the pitch shifter and the shimmer reverb can be driven from a keyboard. Turn on note mode and C3 is unison, C4 is an octave up, and every interval in between is under your fingers while the track runs. Pitch bend is always live at a couple of semitones, and there is optional portamento up to two seconds, so moving between chords glides instead of stepping. The plugin registers as a MIDI effect so hosts route notes into it cleanly.

This is the part that makes it a dub machine rather than a delay with extras. Nearly every colouring stage can be placed before the delay, after it, or inside the feedback path — and the three positions do genuinely different things.

Take the six-stage phaser: a classic all-pass cascade with feedback, rate, depth, mix and an offset between the channels for stereo movement. Put it before the delay and the phased signal is what gets recorded to tape. Put it after and it sweeps the wet echoes while your dry signal stays put. Put it inside the feedback loop and every repeat goes through the cascade again, sinking deeper each pass — at high feedback that stops sounding like a phaser and starts sounding like a flanger eating itself.

The reverbs route the same three ways. After the echo you get an ordinary ambience. Before it, the reverb tail is what the tape records, so the repeats are of a space rather than of a note. Inside the loop, each pass adds more reverb to a signal that is already reverb, which is the washing, blooming texture dub records have been chasing since the seventies.

The tone shaping is split in two for the same reason. An input filter — low cut, high cut, bass and treble — shapes only what reaches the tape, leaving the dry output clean. A separate feedback filter with the same four controls darkens each repeat as it comes round, which is what makes a real tape echo dissolve instead of merely repeating. On top of that sits a resonant multimode filter before the tape — low-pass, high-pass or band-pass, with its own resonance, sweepable into self-oscillation.

Two LFOs and an envelope feed an eight-slot modulation matrix, and any control being modulated shows its range as an arc with a moving dot, so you can see what is pulling on what.

A dispersive spring tank, with the boing a real one has. A modulated plate. A dense sixteen-line hall. Spring into plate in series, and spring and plate in parallel, which are different sounds and not a preset of each other.

A shimmer, whose interval is switchable: octave up by default, or fifths, fourths, an octave down, or two octaves for something much darker or much brighter than the usual shimmer patch. And an eighties gated reverb — a bright plate behind an envelope-keyed gate, for the bloom-then-snap that every snare on every record from 1984 has.

Then convolution, which ships with forty-eight impulse responses: thirty-eight from the Voxengo set plus ten real spaces from the OpenAIR library, including York Minster, Hamilton Mausoleum and a nuclear reactor hall. It will load any impulse of your own as well.

A feedback path this deep will find unity gain eventually, and a tape echo screaming into a mix bus is not a charming accident when it happens during a take. So there is a slow, programme-dependent leveller on the output — the kind of gentle 2:1 you would put across a bus — followed by a fast ceiling catcher just under full scale. It keeps runaway under control without flattening transients, and it is one click to bypass if you want the mess.

The feedback knob turns red as it approaches self-oscillation, so you can see where the edge is before you hear it. Freeze holds the loop indefinitely so you can play over it. Kill feedback empties it on command. Ping-pong throws the repeats across the stereo field, and there is wet ducking so the echoes get out of the way of the dry signal.

And a bypass toggle silences the tape while leaving the whole character chain running — saturation, head bump, high-frequency loss, AGE, the phaser and the reverbs — which turns Doobie into a tape colouration insert with no delay in it at all.