Horns · Guide
See what the air is doing inside the horn
A smooth SPL curve can hide a lot: air moving fast through a narrow section, a pressure peak at a closed end, or two outputs cancelling. The four horn diagnostic graphs read the path at any station you pick and split the sound into each thing that radiates.
Open them
Open horn diagnostics in the horn card adds all four tiles. You can also add each one from the graph picker. They show horn enclosures only.
The four graphs
| Graph | Unit | What it shows |
|---|---|---|
| Horn Particle Velocity | m/s, peak | How fast the air moves at the chosen location: the volume flow divided by the area there. It is not the cone’s speed, and it is not a sum over outputs. |
| Horn Pressure | Pa, RMS, or phase in degrees | The sound pressure inside the path at the chosen location. Switch between Magnitude and Phase. |
| Horn Acoustic Impedance | Pa·s/m³ | Pressure divided by volume flow at the location, as Magnitude, Phase, Resistance or Reactance. It is acoustic, not the electrical impedance in ohms. Where no air flows, it is undefined and left out. |
| Horn Radiating Outputs | dB, or phase in degrees | Each mouth, port and exposed cone on its own, dashed, with their coherent total solid. The outputs add as pressures with their phase, so their dB values do not simply add. |
Pick a location
Velocity, pressure and impedance read one location at a time. Locations are named by path, span and end, such as Main H1 throat, with their position and area. Where a driver enters or a branch joins partway along a span, the two sides are separate locations, marked toward the throat and toward the mouth. Pressure is continuous across the join, but the flow on each side can differ.
An example: the tapped horn
- Constriction
- Peak 5.8 m/s at 38 Hz0.95 m along the path · 600 cm²
- Mouth
- Peak 3.3 m/s at 42 Hz2.50 m along the path · 2,400 cm²
- Closed end
- Peak 1,485 Pa at 40 Hz0.00 m along the path · 400 cm²
- Constriction
- Peak 1,131 Pa at 41 Hz0.95 m along the path · 600 cm²
The tapped horn example at 100 W in half space, simulated when this page was built. The air moves much faster at the constriction, the narrowest station between the closed end and the mouth, than at the mouth itself; a narrow section like this is where to check for noise first. Pressure is higher at the closed end than at the constriction, because the air cannot move there. The tapped horn.
Outputs that add and cancel
Where a design radiates from more than one place, Horn Radiating Outputs shows each one. In a back-loaded horn the front of the cone and the horn mouth both radiate, and the total depends on how they line up in phase.
- Total
- Main mouth
- Direct radiator
The back-loaded horn · The compound horn, which has two mouths.
What they are not
- They are linear. They do not predict turbulence, distortion or compression, and no air-speed warning is applied the way the port velocity check is for a box. Decide your own limit for the air speed in a narrow section.
- A location missing from a comparison enclosure is left out, not drawn at zero.
- Max SPL, excursion and impedance still apply to horns. Max SPL is the lower of two ceilings, the cone reaching Xmax and the driver’s thermal limit, with the thermal rule chosen in the tile’s settings. The default is real input power, the rule Hornresp uses. Max SPL.
- The dashed folded line from the Fold tile is not drawn on these four graphs.
Every graph, unit and display mode in detail: Horn Diagnostic Graphs reference.
Ask your AI
Hand it to your AI
With 00 Simulator connected to Claude, ChatGPT or another MCP client, your assistant runs this same solver on your own workspaces. Copy the prompt and paste it into a chat.
Using 00 Simulator, simulate my horn at the power it is set to and read its horn diagnostics. Where along the path is the particle velocity highest, how high does it get and at what frequency? Then tell me whether any outputs cancel inside the working band.
- Claude
- In a chat, open the + menu, go to Connectors and switch 00 Simulator on.
- ChatGPT
- In a chat, open the + menu, choose Developer mode and select 00 Simulator.
- Claude Code
- Once the server is added, paste it into any session.