# Zone Statistics

The Zone Statistics tool in HOLOPLOT Plan gives you a fast and clear overview of how well your sound system design meets SPL and delay spread targets across your selected coverage areas. This feature is available in both **SPL simulation** and **delay spread simulation** modes.

#### Overview

Zone statistics help quantify **how much of a selected zone** meets your defined performance thresholds. It’s a quick way to assess coverage uniformity (in SPL mode) or clarity (in delay spread mode) without manually inspecting the simulation maps.

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#### How it works

**SPL simulation mode**

In SPL mode, you define a dB range (e.g., **±6 dB**) around a reference value. The tool calculates what **percentage of the selected zone(s)** falls within that range.

* **Reference value**: Based on the selected beam's simulation data.
* **Range input**: Set using the `±` input field (editable via direct input or arrow keys).
* **Result**: Displayed as a percentage (e.g., "97% of the zone is within ±6 dB").

This lets you evaluate the **uniformity of level distribution** across a zone at a glance.

**Delay spread simulation mode**

In delay spread mode, you define a **threshold in milliseconds** (e.g., **under 50 ms**), and the tool shows what percentage of the selected zone meets this clarity criterion.

* **Reference**: The tool considers each grid point’s delay spread value.
* **Threshold input**: Set in milliseconds.
* **Result**: Percentage of the area with delay spread below the chosen value.

This helps you evaluate **temporal clarity** and potential intelligibility issues.

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#### Multi-zone support

You can apply zone statistics to **one or more zones at the same time**:

* Select multiple zones in the Plan viewport.
* Adjust the dB or millisecond range as needed.
* The displayed percentage reflects the **aggregate result** for all selected zones.

This is especially useful when comparing different areas of a venue or validating design performance across a wide audience area.