How to Use Whirl

Whirl is Stem Shovel's looper (Looper in the Tools menu, Whirl in the footer), a loop station that anyone can use, signed in or not: a loop of one to eight bars at a tempo plays round and round while you record layers onto it one pass at a time, from the microphone, the piano or the drum machine. Lay down a beat, add a bass line on the piano, sing over it, and save the whole thing to the Idea Recorder as a take with each layer as its own stem.

The loop

The looper is a device like the drum machine and the piano: a screen with the loop's position, the transport, the source, three settings menus and the volume, with the layers below. Set the tempo (the slider, or Tap it in beside it), the bars (1, 2, 4 or 8) and the beats per bar (4 or 3) in the Timing menu before the first layer; once a layer exists they are fixed until you Clear the loop. The tempo is the session's (and so is the swing), shared with the drum machine, the metronome and the chord player's arpeggiator: change it on any of them, or load a drum preset or a generated beat with a tempo of its own, and the loop follows; once the loop has layers, the session is held to the loop's tempo instead (the drums can still run at half or double it from their own tempo setting). Count in a bar before the first pass gives you a bar of clicks before recording starts; the click can sound on the count-in only, through the loop, or not at all. Both are in the Timing menu.

Play runs the loop (an empty loop runs its transport so you can record the first layer against the click); Stop halts everything. The space bar plays and stops the loop unless the drum machine or the piano panel was the last thing you touched, in which case it works that instrument.

Recording a layer

Choose the source under Input Source: the microphone (it asks for permission the first time), a line in (a second input, for an instrument on an audio interface), the computer (audio from another program), the piano or the drums, each with its own level meter; choosing the piano or the drums opens that instrument if it is not out already. Chords is the chord player (the piano's sounds on a circle of fifths, with its own panel and settings): arm it and the panel opens; it is the same instrument as the piano, so a chords layer is timed and shifted like a piano layer.

Each source but the drums has a small menu button beside it. The microphone's and the line in's choose the device from what your computer has and how it is taken: stereo, or one channel on both sides, which is what an instrument on channel 1 of a stereo interface wants. Computer captures another program through the browser's share picker: pick a tab, a window or the screen and tick "Share audio". Chrome and Edge share a tab's audio anywhere and the whole computer's audio on Windows; on a Mac, only a browser tab's audio can be shared, so route another program through a loopback device such as BlackHole and choose that as the line in instead; Safari cannot share audio. A slider in the computer's menu shifts its layers earlier by the capture's own delay. Each of the three has a Gain slider right under its button, −12 to +24 dB, applied as you play, so the meter and the recording carry it: an interface's line input usually sits well under a microphone's level and wants a boost. The piano and the drums have their own volume under theirs, the same one their panels move. A source's meter runs from the moment it is chosen, so you can check a level before recording. Normalize recorded layers scales each layer from these inputs so its loudest point sits just under full scale, leaving a near-silent one alone. Press Record: from the next bar 1 (after the count-in when the loop was stopped) every full pass of the loop becomes a layer. The button stays lit while recording; press it again and the pass under way is the last layer. Stop halts the loop and drops a pass still recording. A layer appears when its pass ends, so with the default two-bar loop and a count-in the first one lands at the end of the third bar after you press Record; the status line counts it down. Recording the drums starts the drum machine's beat on bar 1 (after the count-in when the loop was stopped) at the loop's tempo, restarting it in step if it was already playing; open the drum machine from the toolbar to choose the beat first. The piano records whatever you play on its panel, keys or MIDI. A loop holds up to 16 layers.

Each layer has a level, a mute and a solo, a waveform with the playhead, and a delete button; Undo removes the last layer.

The inputs' latency

A sung or played layer reaches the computer a little late (the microphone's and the speakers' round trip, usually 10 to 60 ms, more over Bluetooth), which would make it sit behind the beat. The looper shifts microphone and line-in layers earlier by the Input latency setting in the microphone's or the line in's menu. Press Calibrate in the microphone's menu with the speakers on: three clicks play and the microphone measures how late they arrive; the result is remembered in this browser, and the slider nudges it. The drum machine's beat runs on the loop's own clock and needs none. The piano is different: what you play by hand is timed against the loop as you hear it, which your audio output delays a little (the piano's menu shows how much your device reports; Bluetooth adds a lot), so piano layers are shifted earlier by that amount unless you untick Shift piano layers by the output latency there. Hear the microphone through the speakers is off by default, since a laptop's speakers would feed back into its microphone; use headphones if you turn it on.

Save, load and export

Your loop stays in this browser as you work, so a reload or a visit days later brings it back ("back from last time" on the screen); to keep it for good, Save it, which needs an account. The loop's name sits above the screen, like the idea's title in the recorder: a placeholder names it until you type one, and you can change it any time. The Save menu has how many passes the saved mix should run and three buttons: Save stores the loop with every layer, and once saved, saves it again in place; Save as new loop keeps the saved one and starts a separate one; Export to the Idea Recorder lists the loop among your ideas in the recorder, where its layers can go to a song as stems. A saved loop that was not exported lives in the looper only: the Idea Recorder keeps it out of its list unless you tick Show loops there. The screen shows the loop's name and whether it has changed since the save. Saving renders the layers' mix (one, two or four passes long, your choice) and saves it to the Idea Recorder as a new idea's take, with each layer as one of the take's sources, named for what it was. In the recorder, the take's menu then offers Add N stems to song… to put the layers on a song as separate stems, and Add as demo… adds the mix. The loop's tempo, length and layer settings are kept with the idea. New ideas are filed under the account you are currently working in. The Load menu lists every loop you saved, newest first; choose one and it comes back into the looper, layers, tempo and bars, replacing what is there (export that first if you want to keep it). Below the loops, Import a take lists your recent Idea Recorder takes: a saved loop comes in as one layer per source, a recorded take as one layer. With an empty loop the loop's length can follow the take (rounded to 1, 2, 4 or 8 bars at the current tempo); otherwise the take is fitted to the loop's length. Set a start offset for a take that begins before its downbeat. A take only sits on the beat if it was played to the tempo. Below that, Import a stem lists the songs with stems in your accounts: pick a song and press a stem to bring it in as a layer, cut to the loop's length from the same start offset, so a chorus or a riff from a finished song can play under what you record.

Notes and panels

A loop has a note board under the looper, exactly as an idea has in the Idea Recorder: lyrics, chords, what to try next; it saves as you type, and comes back with the loop. On a desktop, the looper and the notes each have a button in their header to pop out into a panel you can drag and resize, and the same button puts them back.

The Practice Amp

Amp under Record from is the Practice Amp (see its own page in these docs): choosing it opens the amp's panel and turns it on, and a layer recorded from it is what you hear through the amp, pedals and all. The slider under the button is the amp's master.