Reference · Tiles
TILEHORNSPA·S/M³Horn Acoustic Impedance
- Shows
- Pressure divided by volume flow at a horn station, as magnitude, phase, resistance or reactance.
- Healthy when
- You are reading the intended station and distinguishing acoustic loading from the amplifier’s electrical load.
- If it is not
- Compare pressure and velocity there, or choose another station if volume flow vanishes.
The tile#
Horn Acoustic Impedance
kPa·s/m³
- Main H2 mouth
- Main H4 mouth
The example compares a narrow station with the mouth; its axis uses kPa·s/m³ to keep the values readable. In the app choose the station and then the display mode. Electrical Impedance, in ohms, is a different tile.
| Mode | Meaning |
|---|---|
| Magnitude | The size of the pressure-to-flow ratio, in Pa·s/m³. |
| Phase | The phase angle of pressure relative to volume flow, in degrees. |
| Resistance | The real part of the acoustic impedance. |
| Reactance | The imaginary part, which can change sign around resonances. |
A closed end needs care#
At exactly zero volume flow the ratio is undefined and the solver can leave it absent. Very small numerical flow can instead give an extremely large ratio. A closed-end throat is therefore a poor starting station for a readable impedance comparison; choose a station farther along the path.
The sign convention treats flow towards the stored segment end as positive. Keep the same location and orientation when comparing resistance, reactance or phase. A missing matching station in another enclosure is omitted, not represented by zero.
What moves it#
| Change | Effect |
|---|---|
| Input power alone | Pressure and flow scale together, so the linear ratio is unchanged. |
| Path length, area or flare | Changes resonances and the load seen at a station. |
| Stuffing or chamber losses | Changes the dissipative and reactive behaviour. |
| Selected station | Reads a different local load within the same horn. |
What to try#
| Try | What it changes |
|---|---|
| Separate the components | Switch between Magnitude, Phase, Resistance and Reactance. |
| Explain a gap | A station with no flow has no defined acoustic impedance; a missing value is not zero. |
| Check amplifier load elsewhere | Use Impedance for electrical impedance in ohms. |
Ask your AI#
Ask your AI
Using 00 Simulator, inspect the acoustic impedance of my horn at a non-zero-flow station and at the mouth. Explain the magnitude, resistance and reactance in the working band, using the pressure and volume flow to explain any extreme values.
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