User Manual
Beat Sync
Everything in music demands a synchronized beat... the metronome click, a drum groove, a delay slap, tremolo pulse, an arpeggio, etc. OnSong accounts for this through a shared beat clock that is constantly in-the-know about tempo, time signature, and when each measure starts. Beat Sync is what starts and synchronizes multiple components in OnSong so you're always in the pocket.
One Tempo, One Clock
There's a single clock for the whole app. It knows three things: the tempo, the time signature, and where you are in the bar — which beat, and which subdivision of that beat. The tempo of the beat clock is usually set by the underlying song being played, but it can be driven by other internal and external factors. These include:
- Song Tempo is the most common way the tempo and time signature is set in lieu of other inputs.
- Ableton Link lets you connect OnSong to other apps or equipment so OnSong can stay in beat and phase with Ableton, a metronome app, or a wrist worn watch.
- MIDI Clock can now hear the difference between each beat and downbeat and use that to update the tempo.
- Backing Tracks are processed when played through the AuxDock to determine their beat grid, changing tempo as needed throughout the track.
Following The Beat
Everything in the OnSong® app now subscribes to the beat clock. The first component to use the beat clock can set the down beat. For instance, if you start the metronome, the downbeat is heard right away and everything else synchronizes with the metronome. If you are actively received beat and phase information through something like Ableton Link or MIDI Clock, the metronome will start on the next beat, but align downbeats to the beat clock. First in wins and everything else follows.
Metronome
This is the most obvious integration of the beat clock including the count-in.
AuxDock Atmosphere
This plays a canvas of sound that can be started, stopped and changed with those changes synchronized to the current beat.
AuxDock Pedalboard
What if your guitar effects could stay in sync with every aspect of the song? The AuxDock features timed pedals that can have time parameters set to a musical subdivision. Quarter, dotted eighth, and so on, following tempo changes as they happen on: - Delay - Tremolo - Phaser - Wah
AuxDock Chordboard
This lets anyone play chords in the song. It uses an arpeggiator and strum system. Beat sync ensures each chord change and note is played at the right time.
AuxDock Drum Rack
Is a full drum machine that ensures the groove, fills, and ending land where you'd expect rather than where you tapped.
AuxDock Virtual Instrument
This is a guitar that can strum or pick to the chords in your song. Beat sync lets it all play in time rather than whenever you touch it.
The clock only runs when something is listening. Nothing is being kept in time, nothing is ticking.
Dynamic Tempo and Meter
A song doesn’t have to hold one tempo anymore. Each sections can carry its own directives and the beat clock is updated when each section is selected:
- {tempo: 72} changes the tempo to the new BPM value.
- {time: 6/8} changes the time signature meter to 6/8. The new meter starts on a clean downbeat rather than part-way through a bar.
- {ramp: 4} glides from the current tempo to new tempo over a number of measures, beats, or seconds rather than immediately. Typing just a number specifies the number beats. Using a syntax like 1,2 would change it over a measure and two beats. Appending an "s" to the end like 2s would define the number of seconds independent of the tempo.
These are live changes, not edits! They move the tempo of everything without rewriting the song's own tempo.
Enabling Beat Sync
Beat Sync appears wherever it's relevant, as a small pulsing LED with the current BPM beside it. The LED blinks on the beat, so you can see at a glance both that sync is on and what tempo it's on.
Tapping it toggles that surface's sync. When you do, a chip floats briefly in the dock — armed, it offers Ableton Link… as the way of sharing the tempo with other devices or that it's been disarmed, confirming that beat sync is off.
Where It Counts
When the metronome counts you in, beat-synced instruments stay silent through the count and start on the first real downbeat. They don't play along with the count and they don't come in late — the first beat is scheduled ahead of time so it lands exactly.
Why It Doesn’t Drift
Two details do most of the work, and they're worth knowing because they explain why beat-synced audio in the OnSong® app stays tight where other approaches wander.
The clock’s grid is anchored to the device's monotonic hardware clock, not to a repeating timer. A timer accumulates a little error on every tick; an anchored grid computes when each beat should happen, so beat ten thousand is as accurate as beat one.
Beat-synced audio is scheduled ahead of time rather than played when the tick arrives. The clock can say precisely when an upcoming beat will occur, so a drum hit is handed to the audio engine in advance with that timestamp attached. If the app is busy for a moment, the audio has already been scheduled and still lands on the beat.
If something sounds like it’s drifting, check whether its Sync is actually on — an effect with Sync off is running on its own rate knob, which is a legitimate setting and looks identical from across the stage.
