Audio Filters¶

Voltricx wraps all Lavalink v4 audio filters in clean, chainable Python classes. You can combine multiple filters simultaneously.

Overview¶

Filter	Class	Effect
Equalizer	`Filters.equalizer`	Adjust individual frequency bands
Karaoke	`Karaoke`	Remove or isolate vocals
Timescale	`Timescale`	Change speed, pitch, and rate
Tremolo	`Tremolo`	Oscillate volume rapidly
Vibrato	`Vibrato`	Oscillate pitch
Rotation	`Rotation`	Stereo panning / 8D audio
Distortion	`Distortion`	Audio distortion effects
ChannelMix	`ChannelMix`	Mix left/right channels
LowPass	`LowPass`	Suppress high frequencies

Getting & Setting Filters¶

# Get the current Filters object
filters = player.filters

# Apply filters back to the player
await player.set_filters(filters)

To reset all filters:

await player.set_filters(voltricx.Filters())

Equalizer¶

15 bands from 0 (deepest bass) to 14 (highest treble). Gain: -0.25 (muted) to 1.0 (doubled).

filters = player.filters

# Set a specific band
filters.equalizer.set_band(band=0, gain=0.25)   # Boost bass

# Set multiple bands at once (resets others to 0)
filters.equalizer.set(bands=[
    {"band": 0, "gain": 0.25},
    {"band": 1, "gain": 0.20},
    {"band": 2, "gain": 0.15},
])

# Reset to flat
filters.equalizer.reset()

await player.set_filters(filters)

Preset: Bass Boost¶

filters = player.filters
for i in range(4):  # Bands 0-3 = bass
    filters.equalizer.set_band(band=i, gain=0.25)
await player.set_filters(filters)

Timescale¶

Changes speed, pitch, and rate independently.

filters = player.filters

# Nightcore (faster + higher pitch)
filters.timescale.set(speed=1.3, pitch=1.3)

# Vaporwave (slower + lower pitch)
filters.timescale.set(speed=0.8, pitch=0.8)

# Chipmunk (high pitch, normal speed)
filters.timescale.set(speed=1.0, pitch=1.5)

# Deep voice (low pitch, normal speed)
filters.timescale.set(speed=1.0, pitch=0.6)

# Slow motion (half speed, keep pitch)
filters.timescale.set(speed=0.5, rate=0.5)

# Reset
filters.timescale.reset()

await player.set_filters(filters)

Parameter	Range	Default
`speed`	> 0.0	`1.0`
`pitch`	> 0.0	`1.0`
`rate`	> 0.0	`1.0`

Karaoke¶

Uses equalization to eliminate part of the audio spectrum, typically targeting vocals.

filters = player.filters

# Enable karaoke
filters.karaoke.set(
    level=1.0,          # Vocal removal strength (0.0–1.0)
    mono_level=1.0,     # Mono level (0.0–1.0)
    filter_band=220.0,  # Filter center frequency (Hz)
    filter_width=100.0, # Filter width
)

# Disable
filters.karaoke.reset()

await player.set_filters(filters)

Tremolo¶

Oscillates the volume at a set frequency to create a shuddering effect.

filters = player.filters
filters.tremolo.set(frequency=4.0, depth=0.75)
await player.set_filters(filters)

Parameter	Range	Default
`frequency`	0.0–14.0 Hz	`2.0`
`depth`	0.0–1.0	`0.5`

Vibrato¶

Like tremolo but oscillates pitch instead of volume.

filters = player.filters
filters.vibrato.set(frequency=4.0, depth=0.5)
await player.set_filters(filters)

Parameter	Range	Default
`frequency`	0.0–14.0 Hz	`2.0`
`depth`	0.0–1.0	`0.5`

Rotation (8D Audio)¶

Rotates the audio around the stereo field — when listened to with headphones, gives a 3D "8D" effect.

filters = player.filters
filters.rotation.set(rotation_hz=0.2)   # Rotation speed in Hz
await player.set_filters(filters)

Parameter	Default
`rotation_hz`	`0.0` (off)

Distortion¶

Applies mathematical distortion using sin/cos/tan functions.

filters = player.filters
filters.distortion.set(
    sin_offset=0.0,
    sin_scale=1.0,
    cos_offset=0.0,
    cos_scale=1.0,
    tan_offset=0.0,
    tan_scale=1.0,
    offset=0.0,
    scale=1.0,
)
await player.set_filters(filters)

ChannelMix¶

Controls how the left and right channels are mixed. Perfect for mono audio or creative panning.

filters = player.filters

# Force mono (both channels = mix of L+R)
filters.channel_mix.set(
    left_to_left=0.5,
    left_to_right=0.5,
    right_to_left=0.5,
    right_to_right=0.5,
)

# Full left (L only)
filters.channel_mix.set(left_to_left=1.0, left_to_right=0.0,
                         right_to_left=1.0, right_to_right=0.0)

await player.set_filters(filters)

Parameter	Range	Default
`left_to_left`	0.0–1.0	`1.0`
`left_to_right`	0.0–1.0	`0.0`
`right_to_left`	0.0–1.0	`0.0`
`right_to_right`	0.0–1.0	`1.0`

LowPass¶

Attenuates frequencies above the cutoff — smoothing out harsh high-end.

filters = player.filters
filters.low_pass.set(smoothing=20.0)
await player.set_filters(filters)

Parameter	Default
`smoothing`	`20.0`

Plugin Filters¶

Pass arbitrary data to Lavalink plugins:

filters = player.filters
filters.plugin_filters.set(deezer={"someKey": "someValue"})
await player.set_filters(filters)

Chaining Filters¶

All filter set() and reset() methods return self, enabling chaining:

filters = voltricx.Filters()
filters.timescale.set(speed=1.3, pitch=1.3)
filters.tremolo.set(frequency=3.0, depth=0.5)
filters.rotation.set(rotation_hz=0.1)
await player.set_filters(filters)

Creating from Scratch¶

filters = voltricx.Filters.from_filters(
    timescale={"speed": 1.3, "pitch": 1.3},
)
await player.set_filters(filters)

Seek After Filter¶

When applying timescale, you may want to re-sync the position:

await player.set_filters(filters, seek=True)

Toggle Helper Pattern¶

async def toggle_nightcore(player: voltricx.Player):
    filters = player.filters
    if filters.timescale.speed > 1.0:
        filters.timescale.reset()
        label = "OFF"
    else:
        filters.timescale.set(speed=1.3, pitch=1.3)
        label = "ON"
    await player.set_filters(filters)
    return label