MIDI Clock BPM
Documentation & User Manual
Introduction
MIDI Clock BPM is a free Mac app that reads MIDI clock and shows its tempo, whether it's playing, and where it is in the song. It's made for anyone who syncs drum machines, sequencers, synths, lighting or video to one clock: to check the tempo that really arrives, to find out why something drifts, or simply to see the BPM on stage.
- macOS 13 Ventura or later (Apple Silicon & Intel)
- A MIDI clock source: a DAW on the same Mac, or a device connected over USB, a MIDI interface or a network session
Download & Installation
Download the latest version from the product page. The app is signed with a Developer ID and notarized by Apple.
- Open the downloaded
.dmgfile. - Drag MIDI Clock BPM.app to your Applications folder.
- Open it. It listens to every MIDI input straight away; no setup or permissions needed.
MIDI Inputs
With Input on All inputs, MIDI Clock BPM follows whichever input sends clock, and shows its name next to the status. It stays with that input while its clock runs, and moves to another one only when that clock stops. Devices you plug in later are picked up automatically.
To follow one source only, choose it in the Input menu. The choice is remembered, also when the device is unplugged.
When more than one input sends clock at the same time, an orange warning names the others. Two clocks are a common cause of sync trouble: devices that listen to both get double ticks. Choose one input to follow it, and switch off the clock you don't need at its source.
Clock from a DAW
MIDI Clock BPM adds a virtual MIDI input called MIDI Clock BPM. A DAW on the same Mac can send its clock there, with no IAC bus or cable needed. It shows up in the app as Virtual port.
- Ableton Live: Settings → Link, Tempo & MIDI. Under MIDI Ports, switch on Clock for the output MIDI Clock BPM.
- Logic Pro: File → Project Settings → Synchronization → MIDI. Tick Clock for the destination MIDI Clock BPM.
- Other DAWs: look for MIDI clock or sync output in the MIDI or sync settings, and choose MIDI Clock BPM as the destination.
Already sending clock to an IAC Driver bus or a hardware port? Then there's nothing to change: MIDI Clock BPM reads those inputs too.
Tempo & Jitter
MIDI clock sends 24 ticks per quarter note. MIDI Clock BPM fits a straight line through the arrival times of up to eight beats of ticks, using the time stamps macOS gives every MIDI message. That makes the tempo exact to a hundredth of a BPM, even when single ticks are a millisecond early or late.
- Big number: the tempo in quarter notes per minute, with one decimal, as in a DAW. It shows a quarter of a beat after the clock starts and is grey until one full beat has arrived.
- Below it: the tempo with two decimals and the jitter: how far the ticks wander from a perfectly steady clock, in milliseconds (RMS).
- Tempo changes: a jump shows within a beat; a small change or a ramp within two to three beats.
- Copy: the copy button puts the tempo on the clipboard.
| Jitter | Typical for |
|---|---|
| Under 0.5 ms | A DAW on the same Mac, or good hardware over USB. Tight. |
| 0.5–2 ms | DIN MIDI with other data on the same cable, USB hubs, network MIDI. Usually fine. |
| Over 2 ms | A busy or overloaded connection. Arpeggiators and synced delays can start to sound loose. |
Transport & Status
| Status | Meaning |
|---|---|
| Waiting for clock | Nothing received yet from the chosen input. |
| Playing (green) | The sender sent Start or Continue and the clock runs. The light pulses on every beat. |
| Stopped (orange) | The sender sent Stop. Many devices keep their clock running while stopped; the tempo then stays live. |
| Clock running (orange) | Clock arrives, but no Start, Continue or Stop has been seen yet, for example because the app was opened mid-song. Tempo only; the bar count starts at the next Start. |
| No clock (red) | The clock stopped without a Stop message: a cable, a crashed app or a device that lost power. The last tempo stays on screen. |
Bar Count & Time Signature
While playing, MIDI Clock BPM counts the bar, beat and sixteenth from the sender's Start, and follows Continue and Song Position messages when you locate in a DAW. The bar below shows a light per beat: orange on the first beat of the bar, blue on the others.
MIDI clock doesn't carry a time signature, so enter it in the two Signature fields, like in a DAW: beats per bar (1–99) over the note value of a beat (1, 2, 4, 8 or 16). In 6/8 a beat is an eighth note, so a bar has six beats. The tempo stays in quarter notes, as in a DAW.
Troubleshooting
“Waiting for clock”
Check that the sender actually sends clock: in a DAW, clock output has to be switched on per port (see Clock from a DAW); on hardware it's often a setting like Clock out or Sync out. If you chose a single input, try All inputs.
No bar count
The status says Clock running: the sender hasn't sent Start since the app opened. Stop and start the sender once.
The bar count is off
Check the time signature fields. Some devices don't send Song Position when you jump around; press stop and play from the start to get back in step.
The tempo is slightly different from the DAW
Compare with the two-decimal value under the big number. A DAW rounds what it shows, and some devices run their clock a tiny bit off the tempo they display; MIDI Clock BPM shows what actually arrives.