# Cone Velocity

> Read peak cone speed, distinguish it from excursion and air speed, and recognise the slowing cone around a vented box’s tuning.

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

This is the cone’s motion shown as speed. Use it to see where the cone is doing the work, then use Excursion to decide whether its travel is acceptable.

- **Shows:** How fast the cone moves, at its peak, at each frequency: m/s, or mm/s below 1 m/s.
- **Healthy when:** It has no limit line. It is the same motion as **Excursion**, shown as speed; the limit to watch is on that tile.
- **If it is not:** Bring it down the way you bring excursion down: less power, a filter, or a different box.

## The tile

_Figure: The cone’s peak speed at two powers, with a dip around tuning._

Vented example at 100 W, half space, 1 m. Simulated when this page was built.

| Cone Velocity | Peak | At |
| --- | --- | --- |
| 100 W | 1.1 m/s | 59 Hz |
| 50 W | 0.8 m/s | 59 Hz |

[Open this example](https://simulator.00aud.io/app?template=vented&power=100). The tile labels small speeds in mm/s and larger ones in m/s. There is no maximum-speed line: it is a diagnostic view of motion, not a separate driver rating.

## Speed is not travel

For a sinusoid, peak cone speed is peak excursion multiplied by 2π and frequency. The same travel therefore means more speed at a higher frequency. A low-speed reading at a very low frequency can still exceed Xmax.

| Frequency in this run | Peak travel | Peak speed |
| --- | --- | --- |
| 20.0 Hz | 8.86 mm | 1.12 m/s |
| 31.6 Hz | 1.80 mm | 0.36 m/s |
| 80.6 Hz | 2.15 mm | 1.09 m/s |

The dip around tuning is where a vented box’s port takes over from its cone. Compare **Port Volume Velocity** to see the volume flow through the port. Multiplying cone speed by the driver’s Sd gives the cone’s own volume flow.

## What moves it

| Change | Result |
| --- | --- |
| Halve the power | 0.71 times the cone speed at the same frequency in this run. |
| Move the tuning | Moves the loading dip and changes the speed on either side. |
| Add a filter | Changes speed in the frequencies where the filter changes voltage. |
| Change listening distance | Changes the SPL at the listener, not the motion at fixed drive. |

## What to try

| Try | What it changes |
| --- | --- |
| [Find the tuning](https://simulator.00aud.io/docs/boxes/vented) | In a vented box the cone slows to a dip at the tuning, where the port takes over. |
| [Read travel from speed](https://simulator.00aud.io/docs/reference/tiles/excursion) | Speed is travel times 2π times frequency, so a slow cone at a low frequency can still be travelling a long way. |
| [Compare with the port](https://simulator.00aud.io/docs/reference/tiles/port-volume-velocity) | Times the driver’s Sd, it is the air the cone moves. Put it beside **Port Volume Velocity**. |

## Ask your AI

**Ask your AI**

> Using 00 Simulator, simulate my vented enclosure at its current power and compare cone velocity, excursion and port velocity around tuning. Explain where the port takes over and whether cone travel exceeds Xmax below it.