The **Frequency Meter Node** (`FrequencyMeterNode`) analyzes an Audio FFT stream and turns selected frequency energy into values that can drive fixtures, gates, colors, and animations.

![Frequency Meter Node](https://unilighter.cc/info/docs/node-graphs/frequency-meter/frequency_meter_ee2c2653.png)

## 🎚️ Analysis Modes

- **Parametric**: Measures the range between **Min Freq (Hz)** and **Max Freq (Hz)** and returns one **RMS** value. Use this for a focused kick, vocal, bass, or effect range.
- **Fixed**: Splits the `20 Hz–20 kHz` spectrum into eight logarithmic bands. Choose a `3 dB/oct` or `4.5 dB/oct` slope, then use the individual band outputs or the complete **Bands** array.

The **Volume** input applies a `0–200%` gain before the selected measurement is calculated. The **Spectrum** display can be enabled in either mode: parametric mode highlights the selected passband, while fixed mode marks all eight fixed bands and labels their centers.

## 🔌 Sockets Reference

| Socket | Mode | Direction | Data Type | Description |
| :--- | :--- | :--- | :--- | :--- |
| **FFT** | Both | Input | `Audio` | Raw FFT stream from an [Audio Input Node](https://unilighter.cc/info/for-ai/docs/node-graphs/audio.md). |
| **Min Freq (Hz)** | Parametric | Input | `Number` | Lower edge of the measured range, from `20` to `20000 Hz`. |
| **Max Freq (Hz)** | Parametric | Input | `Number` | Upper edge of the measured range, from `20` to `20000 Hz`. |
| **Volume** | Both | Input | `Number` | Analysis gain from `0` to `2`. |
| **RMS** | Parametric | Output | `Number` | Energy level inside the selected range (`0.0–1.0`). |
| **32**, **75**, **180**, **420**, **1k**, **2.4k**, **5.6k**, **13k** | Fixed | Output | `Number` | Energy level for each fixed logarithmic band. |
| **Bands** | Fixed | Output | `Number Array` | The eight fixed-band levels in low-to-high order. |

## 💡 Practical Stage Recipes

1. **Sub-Bass Flash**: Use **Parametric** mode with `40–100 Hz`, connect **RMS** to a [Gate Node](https://unilighter.cc/info/for-ai/docs/node-graphs/gate.md), and route the envelope to a strobe or dimmer.
2. **Eight-Band Colorizer**: Use **Fixed** mode and connect individual band outputs to Math or Color logic for a multi-band effect.
3. **Live Spectrum Debugging**: Enable **Spectrum** while tuning the frequency range. The guides show where the passband sits against the live FFT curve.