UserMedia uses MediaDevices.getUserMedia to open up and external microphone or audio input. Check MediaDevices API Support to see which browsers are supported. Access to an external input is limited to secure (HTTPS) connections.

const meter = new Tone.Meter();
const mic = new Tone.UserMedia().connect(meter); => {
	// promise resolves when input is available
	console.log("mic open");
	// print the incoming mic levels in decibels
	setInterval(() => console.log(meter.getValue()), 100);
}).catch(e => {
	// promise is rejected when the user doesn't have or allow mic access
	console.log("mic not open");



new UserMedia (

The level of the input in decibels

) => UserMedia
new UserMedia (
options?:Partial<UserMediaOptions >
) => UserMedia


blockTime #

readonly Seconds

The number of seconds of 1 processing block (128 samples)


channelCount #


channelCount is the number of channels used when up-mixing and down-mixing connections to any inputs to the node. The default value is 2 except for specific nodes where its value is specially determined.

channelCountMode #


channelCountMode determines how channels will be counted when up-mixing and down-mixing connections to any inputs to the node. The default value is "max". This attribute has no effect for nodes with no inputs.

  • "max" - computedNumberOfChannels is the maximum of the number of channels of all connections to an input. In this mode channelCount is ignored.
  • "clamped-max" - computedNumberOfChannels is determined as for "max" and then clamped to a maximum value of the given channelCount.
  • "explicit" - computedNumberOfChannels is the exact value as specified by the channelCount.

channelInterpretation #


channelInterpretation determines how individual channels will be treated when up-mixing and down-mixing connections to any inputs to the node. The default value is "speakers".

context #


The context belonging to the node.

debug #


Set this debug flag to log all events that happen in this class.

deviceId #

readonly string | undefined

Returns an identifier for the represented device that is persisted across sessions. It is un-guessable by other applications and unique to the origin of the calling application. It is reset when the user clears cookies (for Private Browsing, a different identifier is used that is not persisted across sessions). Returns undefined when the device is not open.

disposed #

readonly boolean

Indicates if the instance was disposed. 'Disposing' an instance means that all of the Web Audio nodes that were created for the instance are disconnected and freed for garbage collection.

groupId #

readonly string | undefined

Returns a group identifier. Two devices have the same group identifier if they belong to the same physical device. Returns null when the device is not open.

input #


label #

readonly string | undefined

Returns a label describing this device (for example "Built-in Microphone"). Returns undefined when the device is not open or label is not available because of permissions.

mute #


Mute the output.

const mic = new Tone.UserMedia(); => {
	// promise resolves when input is available
// mute the output
mic.mute = true;

name #


numberOfInputs #

readonly number

The number of inputs feeding into the AudioNode. For source nodes, this will be 0.

const node = new Tone.Gain();

numberOfOutputs #

readonly number

The number of outputs of the AudioNode.

const node = new Tone.Gain();

sampleTime #

readonly Seconds

The duration in seconds of one sample.


state #

readonly "started" | "stopped"

Returns the playback state of the source, "started" when the microphone is open and "stopped" when the mic is closed.

static supported #

readonly boolean

If getUserMedia is supported by the browser.

static version #


The version number semver

volume #

Param<"decibels" >

The volume of the output in decibels.


chain #

Connect the output of this node to the rest of the nodes in series.

const player = new Tone.Player("");
player.autostart = true;
const filter = new Tone.AutoFilter(4).start();
const distortion = new Tone.Distortion(0.5);
// connect the player to the filter, distortion and then to the master output
player.chain(filter, distortion, Tone.Destination);
chain (
...nodes:InputNode []
) => this

close #

Close the media stream

close ( ) => this

connect #

connect the output of a ToneAudioNode to an AudioParam, AudioNode, or ToneAudioNode

connect (
destination:InputNode ,

The output to connect to

outputNum= 0:number ,

The output to connect from

inputNum= 0:number

The input to connect to

) => this

disconnect #

disconnect the output

disconnect (
destination?:InputNode ,
outputNum= 0:number ,
inputNum= 0:number
) => this

dispose #

Dispose and disconnect

dispose ( ) => this

static enumerateDevices #

Returns a promise which resolves with the list of audio input devices available.

Tone.UserMedia.enumerateDevices().then((devices) => {
	// print the device labels
	console.log( => device.label));
enumerateDevices ( ) => Promise<MediaDeviceInfo [] >
The promise that is resolved with the devices

fan #

connect the output of this node to the rest of the nodes in parallel.

const player = new Tone.Player("");
player.autostart = true;
const pitchShift = new Tone.PitchShift(4).toDestination();
const filter = new Tone.Filter("G5").toDestination();
// connect a node to the pitch shift and filter in parallel, filter);
fan (
...nodes:InputNode []
) => this

get #

Get the object's attributes.

const osc = new Tone.Oscillator();
get ( ) => UserMediaOptions

static getDefaults #

Returns all of the default options belonging to the class.

getDefaults ( ) => UserMediaOptions

immediate #

Return the current time of the Context clock without any lookAhead.

setInterval(() => {
}, 100);
immediate ( ) => Seconds

now #

Return the current time of the Context clock plus the lookAhead.

setInterval(() => {
}, 100);
now ( ) => Seconds

open #

Open the media stream. If a string is passed in, it is assumed to be the label or id of the stream, if a number is passed in, it is the input number of the stream.

open (
labelOrId?:string | number

The label or id of the audio input media device.With no argument, the default stream is opened.

) => Promise<this >
The promise is resolved when the stream is open.

set #

Set multiple properties at once with an object.

const filter = new Tone.Filter().toDestination();
// set values using an object
	frequency: "C6",
	type: "highpass"
const player = new Tone.Player("").connect(filter);
player.autostart = true;
set ( ) => this

toDestination #

Connect the output to the context's destination node.

const osc = new Tone.Oscillator("C2").start();
toDestination ( ) => this

toFrequency #

Convert the input to a frequency number

const gain = new Tone.Gain();
toFrequency (
) => Hertz


Connect the output to the context's destination node. See toDestination

toMaster ( ) => this

toSeconds #

Convert the incoming time to seconds. This is calculated against the current Tone.Transport bpm

const gain = new Tone.Gain();
setInterval(() => console.log(gain.toSeconds("4n")), 100);
// ramp the tempo to 60 bpm over 30 seconds
Tone.getTransport().bpm.rampTo(60, 30);
toSeconds (
) => Seconds

toString #

Convert the class to a string

const osc = new Tone.Oscillator();
toString ( ) => string

toTicks #

Convert the input time into ticks

const gain = new Tone.Gain();
toTicks (
time?:Time | TimeClass
) => Ticks