Simulating Delay Spread
Use Delay Spread simulation mode to visualize how direct sound energy from multiple beams arrives over time. This mode displays the time dispersion of arriving signals, rendered as heat maps on your Audience Zones. The simulation results help you assess whether the direct sound contributions from different beams arrive within an acceptable time window.
Delay Spread is calculated from the arrival times and relative sound energies of each beam at every simulation point. The result is a single metric per grid point that expresses the width of the energy-time distribution i.e. how much the direct sound is spread out in time. In this context, lower values are better: a Delay Spread below 10 ms generally indicates very coherent arrival, while values above 50 ms often suggest audible echoes and degraded intelligibility.
The Delay Spread metric used in HOLOPLOT Plan is derived from the mean absolute deviation of arrival times, weighted by signal energy. Importantly, this simulation only accounts for direct sound and does not simulate room reflections.
Delay Spread mode uses a fixed color scale to provide consistent reference across simulations. This ensures that a given value (e.g., 20 ms) is always shown using the same color, regardless of the overall range in the view. For clarity, the color map is different from that used in SPL simulations.
Delay Spread simulation provides powerful insight when working with distributed beam layouts or long-throw configurations, helping identify regions that may benefit from beam adjustments or additional time alignment.
Environmental Conditions
When Delay Spread simulation is enabled, environmental conditions can be used to test how a preset will perform under certain atmospheric circumstances, which can be done using the Env. Condition drop down.
All the environmental conditions in your project will be visible in the dropdown. Selecting an environmental condition will allow you to view how the environmental condition in the selected preset will perform. If it's the same as active, you will view the simulation under the same conditions the preset has been optimized for. If you select a different environmental condition, you will be able to see how the environmental condition of the selected preset will perform under different temperature, humidity, and atmospheric pressure conditions.
Acoustic Shadowing
In Delay Spread simulation mode, you can activate acoustic shadowing to account for obstructions between the array and listening positions. When enabled, the simulation ignores contributions from beams that are occluded by geometry—such as walls, ceilings, or other structures—at each grid point. This provides a more realistic representation of how sound actually propagates in complex spaces, especially when working with indirect sightlines or distributed arrays. Activating acoustic shadowing can reveal zones where time dispersion improves due to blocked late arrivals, or conversely, where missing early energy leads to poor coherence.
Zone Resolution
Activating the Zone Resolution button allows you select a specific resolution for the simulation. Available options are High (0.2 meters), Medium (2 meters), Low (4 meters), and Minimum (8 meters), giving control over the level over speed of simulation vs. level of detail. Lower resolutions can significantly speed up the simulation process, making them ideal for quickly assessing designs or running early simulations before finalizing a setup. This feature is particularly beneficial for intricate, large-scale projects.
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