# Filter

**In the desktop app.** Filter is a device of the desktop app, arriving in its beta; the web studio does not have it. The examples on this page are made with a reference version of the effect, applied to sound from the studio's engine: they show what each control does, and the device itself may differ a little in character.

## What it is for {#filter}

A **filter** removes part of a sound's range: everything above a frequency, everything below it, or everything except a band around it. Where an [EQ](/manual/equaliser) is for careful correction, a filter is for character and for movement. Closing it makes a sound dark and distant; opening it brings the sound forward, and doing that slowly over a few bars is one of the oldest ways to build tension in a song.

Reach for it when a part should sit behind the others, when a whole section should sound as if heard through a wall, or when a sound should change while it plays. The synth has a filter of its own, the [cutoff](/manual/instruments#cutoff); this device does the same to any track.

<AudioSet title="A filter opening over two bars" :examples="[['filter-off', 'No filter'], ['filter-sweep', 'Opening']]" />

## Shape {#filter-shape}

Which part of the sound is kept:

- **Low-pass**: keeps the low part, removes the top. Darker, further away.
- **High-pass**: keeps the top, removes the low part. Thinner, lighter.
- **Band-pass**: keeps a band around one frequency and removes both sides. Small, like a telephone or an old radio.

<AudioSet title="Shape" :examples="[['filter-low-pass', 'Low-pass'], ['filter-high-pass', 'High-pass'], ['filter-band-pass', 'Band-pass']]" />

## Frequency {#filter-frequency}

Where the filter cuts, in hertz. This is the control you move: with [automation](/manual/automation), it is how a filter opens and closes over time.

## Resonance {#filter-resonance}

A boost right at the cutting frequency. A little adds a whistling, vocal edge that makes the filter's movement easy to hear. A lot rings like a note of its own.

<AudioSet title="Resonance" :examples="[['filter-resonance-low', 'None'], ['filter-resonance-high', 'High']]" />