> ## Documentation Index
> Fetch the complete documentation index at: https://comfytv.org/llms.txt
> Use this file to discover all available pages before exploring further.
# Audio Reactive
> Turn a frequency band's loudness over time into animation keyframes — so a parameter follows the music's energy.
## What this node does
**Audio Reactive** tracks the loudness envelope of a chosen frequency band (bass, mid, high, full, or a custom range) across the whole track and converts it into a stream of animation **keyframes**. As the bass thumps, the mapped field rises and falls with it. Unlike **Audio Beats & Notes** (which fires on discrete events), this produces a smooth, continuous curve you can attack/release-shape and remap to any range.
It accepts a `COMFYTV_AUDIO` snapshot or a `COMFYTV_VIDEO` (its audio track is used; audio takes priority). It outputs `COMFYTV_TEXT` keyframes and has a ▶ **Run**.
To feed native ComfyUI `AUDIO` in or out, insert a **Bridge** — see [bridges.md](https://github.com/jtydhr88/ComfyTV/blob/main/docs/bridges.md).
## When to use it
* Make an object's scale breathe with the bass of a music track.
* Drive opacity, position, or rotation from the overall energy of a mix.
* Create continuous audio-driven motion rather than beat-by-beat pulses.
## Parameters
### band
Which frequency range to follow: `bass` (default, 20–160 Hz), `mid` (160–2000 Hz), `high` (2000–8000 Hz), `full` (20–16000 Hz), or `custom` (use **freq\_lo**/**freq\_hi**).
### freq\_lo / freq\_hi
Custom band edges in Hz, used only when **band** is `custom`. **freq\_lo** range **10 to 16000**, default **40**; **freq\_hi** range **20 to 16000**, default **200**.
### attack
How quickly the envelope rises when energy increases, in seconds. Range **0.001 to 1.0**, default **0.02**. Short = snappy response to transients.
### release
How quickly the envelope falls when energy drops, in seconds. Range **0.01 to 2.0**, default **0.25**. Longer = smoother, more sustained motion.
### rate
Keyframes generated per second (temporal resolution of the curve). Range **1 to 60**, default **10**. Match it to your output frame rate for smooth motion.
### min\_value / max\_value
The output range the envelope is remapped into: quietest maps to **min\_value**, loudest to **max\_value**. Both range **-1000 to 1000**; defaults **0** and **1**. Swap them to invert the response.
### gain
Multiplier applied to the envelope before remapping. Range **0.1 to 8**, default **1.0**. Raise it to make a quiet track drive the full range.
### field
Which animation field the keyframes drive: `v` (default), `scale`, `opacity`, `x`, `y`, or `rotation`.
## Outputs
| Output | Type | Meaning |
| ------------- | -------------- | ----------------------------------------------------------------- |
| **keyframes** | `COMFYTV_TEXT` | The chosen **field** keyed to follow the band's loudness envelope |
## Tips
* Lower **attack** for punchy, transient-following motion; raise **release** to avoid jittery flicker.
* If a quiet mix barely moves the field, raise **gain** or narrow **min/max** — or pick a busier band.
* Set **rate** to your project's fps so keyframes land on frames.
## Related nodes
* **Audio Beats & Notes** — discrete beat/onset events instead of a continuous envelope.
* **Audio Meter Overlay** — burn a live level meter onto a video for reference.