# Tempo & Signature Change
The Tempo and Signature tracks are global tracks that control the project's overall tempo and time signature. They are unique, always docked at the top of the track list.
To show or hide the Tempo and Signature tracks, click the BPM/SIG button in the track list header. This button toggles the visibility of both tracks simultaneously.
## Tempo Changes
The Tempo Track allows you to create dynamic tempo changes throughout your project using an automation lane. It consists of tempo points and the lines that connect them.
### **Tempo Points**
A tempo point is a node that defines a specific BPM value at a specific point in time.
* Adding Points:
* Click on the curve to create a new tempo point at that position.
* Click and drag to create a point and immediately adjust its position and BPM value.
* Adjusting Points:
* Drag a point vertically to change its BPM value, or horizontally to change its timing. A point cannot be moved past its adjacent points.
* By default, points snap to the grid when moved horizontally. Hold Ctrl / ⌘Command while dragging to disable snapping.
* You can also type in a value in the context menu by right-clicking on a point.
* Deleting Points: Double-click a point, or right-click it and select 'Delete' from the menu.
{% hint style="info" %}
Note: Every project starts with a default tempo point of 120 BPM at the beginning. This initial point cannot be moved or deleted, but you can change its BPM value.
{% endhint %}
### Adjusting Tempo Curves
The line between two tempo points represents the tempo transition. By default, this is a linear (straight line) change.
* Hover over the line segment to reveal a curve handle at its center.
* Drag this handle vertically to adjust the curve, creating a smoother or more abrupt tempo transition.
* Double-click the curve handle to reset the transition back to a straight line.
### Tempo Brush
The Tempo Brush offers a different way to edit tempo by "drawing" it.
* Click the Tempo Brush icon on the Tempo Track's header to enable it.
* With the brush active, you can click and drag directly on the track to draw a continuous tempo curve. This process creates a series of fine-grained tempo points automatically.
### Adjusting Tempo Curve Limits
By default, the tempo curve operates within a display range of **60-180 BPM**.
Should you adjust a tempo point beyond this default range, the upper and lower limits of the display will automatically adapt to accommodate your new tempo point.
For manual control, you can expand the [Mixer](/project/mixing/mixer.md) panel and directly input your desired upper and lower limits for the tempo curve's display.
{% hint style="info" %}
ACE Studio's supported tempo range for a project is **10-360 BPM**.
{% endhint %}
## Time Signature Changes
The Signature Track uses markers to set the time signature for different sections of your project.
Signature Markers are represented as cards that must be placed at the beginning of a measure.
* Adding Markers: Hover your mouse over the start of a measure that doesn't have a marker. A translucent + icon will appear. Click it to add a new signature marker, which will initially copy the value of the previous marker.
* Adjusting Markers:
* Drag a marker to move it to a different measure.
* Click a marker to select it. Once selected, you can copy, paste, or delete it.
* Editing Marker Values:
* Double-click a marker to enter edit mode.
* You can edit the numerator and denominator separately. Press Tab to switch between the two input fields.
* Press Enter or click elsewhere to confirm the change.
{% hint style="info" %}
Note: Every project starts with a default 4/4 signature marker at the beginning. This marker cannot be moved or deleted, but its value can be edited.
{% endhint %}
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