# Horn Particle Velocity

> Inspect peak air speed at a horn station, find narrow passages, and compare both sides of driver entries without confusing it with cone speed.

Source: https://simulator.00aud.io/docs/reference/tiles/horn-particle-velocity

This tile shows peak air speed at a chosen point inside the horn. Inspect the narrow passages and the stations around driver entries, not only the mouth.

- **Shows:** Peak air-particle speed in m/s at a chosen station inside the horn.
- **Healthy when:** Speed is acceptable for the passage and output you intend to use; the tile has no automatic speed limit.
- **If it is not:** Inspect narrow stations, then compare a larger area or lower drive and recheck SPL.

## The tile

_Figure: Horn Particle Velocity at Main H1 throat, Main H2 mouth, Main H4 mouth in the tapped-horn example._

Tapped-horn example at 100 W, half space, 1 m. Stations are measured from the closed end. Simulated when this page was built.

| Station | Position | Area | Peak | At |
| --- | --- | --- | --- | --- |
| Main H1 throat | 0.00 m | 400 cm² | 0.00 m/s peak | 10.7 Hz |
| Main H2 mouth | 0.95 m | 600 cm² | 5.78 m/s peak | 38.3 Hz |
| Main H4 mouth | 2.50 m | 2,400 cm² | 3.33 m/s peak | 42.2 Hz |

At Main H2 mouth, the 600 cm² passage peaks at 5.8 m/s near 38.3 Hz. The mouth peaks at 3.3 m/s. The closed-end throat is almost stationary, so leaving the selection at its default would miss the faster air farther along this horn.

The value is local volume flow divided by local area, expressed as sine-peak speed. It is neither the cone’s speed nor a sum over the horn’s radiating outputs. The tile has one magnitude view and no port-style warning line.

## Read both sides of a connection

Station names identify path, span and end. Where a driver enters or a branch joins, locations may distinguish the side toward the throat from the side toward the mouth. Pressure can be continuous while flow differs because a source or branch adds or removes flow there.

| Try | Check afterwards |
| --- | --- |
| A larger area at the constriction | The new speed and the changed SPL. Geometry changes the loading as well as the opening area. |
| Less drive | Lower speed and lower output at the same geometry. |
| A filter outside the useful band | Whether the speed peak falls without losing wanted output. |
| A different station | That it exists in every comparison enclosure. Missing stations are left out. |

> **The model stays linear** There is no simulated turbulence or air-speed compression and no universal horn speed limit applied here. Judge the passage shape and intended use, and validate a real build with measurements.

## What to try

| Try | What it changes |
| --- | --- |
| [Inspect the constriction](https://simulator.00aud.io/docs/horns/diagnostics) | Choose a station at a narrow part of the path, not just the mouth. |
| Compare both sides of an entry | Flow changes where a driver or branch enters, so check the stations either side. |
| [Test more area](https://simulator.00aud.io/docs/reference/tiles/horn-editor) | Preview a larger passage and compare its response as well as its speed. |

## Ask your AI

**Ask your AI**

> Using 00 Simulator, find the highest particle velocity across every station of my horn at its current power. Report its station, local area and frequency, then preview a larger passage there and compare the new velocity and SPL before saving.