> For the complete documentation index, see [llms.txt](https://docs.lmms.io/user-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lmms.io/user-manual/jian-ti-zhong-wen/xiao-guo-qi-cha-jian/spectrum-analyzer-pin-pu-fen-xi-yi.md).

# Spectrum Analyzer（频谱分析仪）

## Spectrum Analyzer in 1.2 and earlier

<figure><img src="https://3710990805-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZRacsG2wvxpXwri0XH6G%2Fuploads%2FleZmg0YtW9MbKexE38Bu%2Fimage.png?alt=media&amp;token=b2504c5a-8f1b-4b16-8c42-8fa0bc09eeee" alt=""><figcaption><p>Spectrum Analyzer</p></figcaption></figure>

This plugin visualizes the frequencies present in the signal it monitors.

### Graph

* **X axis:** shows frequencies from 20 Hz to 20,000 Hz, divided into [octaves](https://en.wikipedia.org/wiki/Octave_\(electronics\)) (this makes the X axis appear nonlinear).
* **Y axis:** shows amplitude from 40 dB to -60 dB (displayed linearly with respect to decibels).

### Buttons

* **Linear Spectrum:** toggles linear display of frequencies (rather than by octaves).
* **Linear Y axis:** toggles linear display of amplitude (rather than by decibels).

## Spectrum Analyzer in 1.3 and later

<figure><img src="https://3710990805-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZRacsG2wvxpXwri0XH6G%2Fuploads%2FWoJgbwwqkGgnGxERJrbk%2Fimage.png?alt=media&amp;token=3c60ed3d-d5fe-4b04-be12-6a8d484d393f" alt="" width="323"><figcaption><p>Spectrum Analyzer</p></figcaption></figure>

* \
  **Frequency Range :** alters the range of displayed frequencies.
* **Amplitude Range :** alters the range of displayed amplitude.
* **FFT Block Size :** alters the frequency resolution of the display (Higher resolutions come at the cost of FPS).
* **FFT Window Type :** changes algorithm used to remove FFT-related noise.
  * Blackmann-Harris displays the least noise but has low frequency resolution.
  * Rectangular displays the most noise but has high frequency resolution.

#### Graph <a href="#graph-1" id="graph-1"></a>

* **X axis:** shows frequencies based on the Frequency range drop-down menu.
* **Y axis:** shows amplitude based on the Amplitude range drop-down menu.

Clicking in the spectrum/waterfall display adds a ruler/cursor with value readouts.

#### Advanced <a href="#advanced" id="advanced"></a>

* **Envelope Res:** alters the resolution of the Peak envelope ("Peak Hold").
* **Spectrum Res:** alters the resolution of the display curve with fill-in color.
* **Falloff Factor:** alters the speed at which the peak envelope ("Peak Hold") falls to zero.
* **Averaging Weight:** alters how the display curve reacts to new samples.
  * High value: fast reaction, low jitter reduction. enables real-time spectrogram.
  * Low value: slow reaction, high jitter reduction.
* **Waterfall Height:** alters the time range, or the amount of temporarily stored frames, of displayed frequencies in the Waterfall display.
* **Waterfall Gamma:** alters the amount of gamma correction in the Waterfall display.
* **Window Overlap:** alters how many times each FFT sample is processed (higher values can help improve FPS).
* **Zero Padding:** improves resolution when using a smaller FFT Block size, at the cost of performance.