# Group Delay

> How to read the Group Delay tile in 00 Simulator: how late each frequency arrives, in milliseconds, and what box, tuning and filters do to it.

Source: https://simulator.00aud.io/docs/reference/tiles/group-delay

How late each frequency arrives, in milliseconds, worked out from how fast the phase turns. It peaks near a box’s tuning and a filter’s corner, so it is the tile for comparing how tight different bass designs are in time.

- **Shows:** How late each frequency arrives, in ms, worked out from how fast the phase turns. EQ and filters are included.
- **Healthy when:** Delay stays low through the band you care about, with no tall, narrow peak.
- **If it is not:** A sealed box or a higher tuning lowers the peak; a high-pass adds to it, more the steeper it is. Compare the options here.

## The tile

_Figure: The Group Delay tile for the vented example, peaking near its 32 Hz tuning._

Ciare 12.00SW in the 55 L vented example tuned to 32 Hz, at any power, half space, 1 m. Simulated when this page was built.

| Group Delay | Peak | At |
| --- | --- | --- |
| Vented example | 26.9 ms | 31 Hz |

The vented example peaks at 26.9 ms near 30.9 Hz, just below its 32 Hz tuning, and falls to 1.9 ms by 100 Hz. At the peak, sound at that frequency arrives as late as if it came from 9.2 m further away.

- [Open this example](https://simulator.00aud.io/app?template=vented) in the simulator and add the tile, then hover the curve for the delay at a frequency.
- Each visible enclosure draws its own line in its colour.
- The delay includes EQ and filters. The time sound takes to reach you does not count: **Listening distance** does not change this tile.

## How to read it

- It is the slope of the [Phase](https://simulator.00aud.io/docs/reference/tiles/phase) tile: where the phase turns fast, that frequency arrives late.
- The peak sits near the tuning of a vented or passive-radiator box and near the corner of a high-pass. A few octaves above them, the delay is small.
- There is no single number that is too much for every system. Compare designs on the same tile, at the frequencies your music uses.
- A box’s line stays between 0 and 100 ms. A horn’s line can dip below 0 ms, and it breaks where the horn’s outputs cancel, because the delay is undefined there.

## Box, tuning and filters

The vented example’s driver in the same 55 L, sealed and vented, and vented with a 25 Hz high-pass.

_Figure: Group delay of the Ciare 12.00SW in 55 L: sealed, vented at 32 Hz, and vented with a 25 Hz high-pass._

Ciare 12.00SW in 55 L, sealed and vented at 32 Hz, the high-pass a Butterworth 24 dB/oct. Half space, 1 m, simulated when this page was built.

| Design | Peak | At | At 30.9 Hz |
| --- | --- | --- | --- |
| Sealed, 55 L | 10.3 ms | 10.0 Hz | 4.5 ms |
| Vented, 32 Hz | 26.9 ms | 30.9 Hz | 26.9 ms |
| Vented with a 25 Hz high-pass | 43.8 ms | 29.4 Hz | 42.9 ms |

- Sealed, the same driver has 4.5 ms of delay at 30.9 Hz against 26.9 ms vented. It pays in bass: F3 is 81.2 Hz sealed against 30.3 Hz vented.
- A high-pass below the tuning protects the cone, and adds its own delay on top: the peak rises from 26.9 ms to 43.8 ms.

## What moves it

A lower tuning reaches deeper, and the bass there arrives later.

| Vented example tuned to | Peak delay | F3 |
| --- | --- | --- |
| 28 Hz | 28.8 ms at 26.1 Hz | 29.6 Hz |
| 32 Hz | 26.9 ms at 30.9 Hz | 30.3 Hz |
| 36 Hz | 25.5 ms at 35.7 Hz | 32.6 Hz |

The steeper the filter, the more delay it adds.

| Vented example with a 25 Hz high-pass | Peak delay |
| --- | --- |
| No filter | 26.9 ms at 30.9 Hz |
| Bessel, 12 dB/oct | 32.0 ms at 30.9 Hz |
| Butterworth, 12 dB/oct | 33.8 ms at 30.9 Hz |
| Linkwitz-Riley, 24 dB/oct | 40.9 ms at 30.1 Hz |
| Butterworth, 24 dB/oct | 43.8 ms at 29.4 Hz |

Power and **Listening distance** leave the tile alone: at 200 W the curve is the same as at 1 W (the largest difference is 0.0 ms).

## Settings and controls

| Control | Where | What it does |
| --- | --- | --- |
| **Y-axis settings** | Tile header | Starts on **Auto**, which fits the lines in 5 ms steps and keeps room below 0 ms. **Manual** takes a **Min** and **Max**. |
| **Add note** | Right-click the chart | A note at the frequency you clicked. |

The tile has no **EQ** button. Edit filters on [SPL (dB)](https://simulator.00aud.io/docs/reference/tiles/spl#eq-on-the-tile), the [EQ Editor](https://simulator.00aud.io/docs/reference/tiles/eq-editor) tile or **EQ / filters** in the Driver panel, and this tile follows.

## What to try

| Try | What it changes |
| --- | --- |
| [Compare a sealed box](https://simulator.00aud.io/docs/boxes/sealed) | The same driver sealed has far less delay near the tuning, and less deep bass. |
| [Try a gentler high-pass](https://simulator.00aud.io/docs/guides/eq-and-filters#slopes) | A 12 dB/oct high-pass adds less delay than a 24 dB/oct one at the same frequency. |
| [Read the phase](https://simulator.00aud.io/docs/reference/tiles/phase) | **Phase** shows the turn this tile is worked out from. |

## Ask your AI

**Ask your AI**

Your assistant runs the same solver on your own designs through the 00 Simulator connector.

> Using 00 Simulator, simulate my open workspace and tell me each enclosure’s peak group delay and the frequency it is at. Then try a 25 Hz high-pass at 12 and at 24 dB/oct on each vented box without saving, and tell me how much each adds to the peak and to F3.