# Offset-driver horn

> How to model an offset-driver horn in 00 Simulator: the driver entry position, throat and rear chambers, a sealed or ported rear chamber, diagnostics, folding and Hornresp export.

Source: https://simulator.00aud.io/docs/horns/offset-driver-horn

One face of the diaphragm enters the horn partway along, rather than at the throat. The section of path behind the entry is closed, and it works as a side branch that cancels a band of frequencies you choose.

_Figure: The offset-driver horn drawn by the simulator's schematic, with its chambers, paths and outputs._

The default horn path the simulator starts a new horn with, with a 15 L sealed rear chamber, with a B&C 10PS26. Driver entry position: 20 % · 24 cm. Drawn by the simulator when this page was built.

## How it connects

The path starts at a closed end. The front of the cone enters at the driver entry position; the back of the cone loads the rear chamber.

The closed section between the end and the entry puts a notch in the response. Designers use it to cancel an unwanted peak above the working band.

## When to use it

### Good for

- Front-loaded designs whose first upper peak needs taming without stuffing.
- Subwoofer horns that would otherwise have a strong resonance just above the band.

### Watch for

- The further the entry sits from the closed end, the lower the notch. Move it too far and the notch lands inside the working band.
- With the rear chamber at 0 L, the back of the cone radiates directly and shows as a Direct radiator output.

## What you set

Set the enclosure type to **Horn**, then choose **Offset-driver** under **Horn type**, in the enclosure panel or in the **Horn Editor**’s path bar.

### In the horn card

The horn card in the enclosure panel lists each path as a row: click one to open that path in the **Horn Editor**. The card also sets:

| Control | What it sets |
| --- | --- |
| **Throat chamber** | **Volume**, and its **Cross-section** under **Advanced**. |
| **Rear chamber** | **Loading**: **Sealed** or **Port**, and **Volume**. At 0 L the back of the cone radiates directly. |

### In the Horn Editor

The path itself is set on the **Horn Editor** tile. Drag it in the drawing, or switch the tile to **Table** to type each value:

| Control | What it sets |
| --- | --- |
| **Main horn** | The area at the closed end, then up to eight spans, each with a **Flare**, a **Length** and the **Area** where it ends. |
| Driver marker | The driver entry position, in cm from the closed end. Switching to this type from a horn whose entry sits at the closed end moves it a fifth of the way along. |

The driver marker can be dragged along the path. The drawing starts at the closed end. [How the Horn Editor works](https://simulator.00aud.io/docs/horns/editor).

## What the driver entry position does

Only the driver entry moves. Near the closed end there is no notch below 500 Hz. Further along, a deep notch appears and moves down as the closed section grows, while the bottom of the band extends a little.

_Figure: Simulated SPL of the offset-driver horn for 3 values of driver entry position: 10 % · 12 cm, 20 % · 24 cm, 35 % · 42 cm._

The default horn path the simulator starts a new horn with, with a 15 L sealed rear chamber. Only the driver entry position changes between the lines. Simulated when this page was built.

Driver entry position, SPL: B&C 10PS26, Half Space · 1.0 m · 50 W.

| Driver entry position | −3 dB |
| --- | --- |
| 10 % · 12 cm | 100 Hz |
| 20 % · 24 cm (the design drawn above) | 91 Hz |
| 35 % · 42 cm | 85 Hz |

## Diagnostics and stuffing

The one horn output is the Main mouth. The Rear port appears when the rear chamber is ported, and a Direct radiator when it is 0 L. Locations include the closed end and both sides of the entry point. [Reading the horn diagnostics](https://simulator.00aud.io/docs/horns/diagnostics).

Any span of the horn can be stuffed, including the closed section behind the entry. [How stuffing works](https://simulator.00aud.io/docs/horns/stuffing).

## Folding and Hornresp

- **Folding:** Available. The **Fold** tile keeps the closed end capped. Its **Driver entry** chip shows where the driver lands on the folded path, and its **Hornresp** tab gives OD, OD1 or OD2 values and the rear chamber volume.
- **Hornresp export · OD, OD1 or OD2:** The driver must enter at S2, S3 or S4. A ported rear chamber is written as Rear Vented, a mapping that has not yet been checked against a native Hornresp capture.
- **Checked against Hornresp:** 16 native Hornresp cases of this type are re-simulated in the regression tests. 13 of 13 agreement checks meet their tolerances, and 3 more track stuffing-model differences without claiming agreement.

[Folding a horn into a cabinet](https://simulator.00aud.io/docs/horns/folding) · [Exporting to Hornresp](https://simulator.00aud.io/docs/horns/hornresp)

## Try it

_Interactive walkthrough in the page: the simulator's own tiles running a short demo._

There is no example for this type yet. Open the simulator, add an enclosure, set its type to **Horn** and choose **Offset-driver** under **Horn type**. It starts from the default horn path.

- [Open the simulator](https://simulator.00aud.io/app)

## Ask your AI

**Ask your AI**

With 00 Simulator connected to Claude, ChatGPT or another MCP client, your assistant runs this same solver on your own workspaces.

> Using 00 Simulator, add an offset-driver horn to my open workspace for the driver I am using now, with a 15 L sealed rear chamber. Try driver entry positions of 10 %, 20 % and 35 % without saving, simulate each at 50 W and show me where the notch lands.