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Background Audio Response

A background audio response allows researchers to record any sounds captured by participants’ microphone during a trial, without any interactions required from participants. This is a background response, meaning that it is invisible to participants (unless the volume_visualizer property is to true).

Recommended Practices

  • This feature works most reliably in Chrome and Firefox.
  • Please clearly communicate to your participants that they are being recorded on relevant trials.

Required Properties

type

  • Definition: The type of response
  • Possible values: For a background audio response, type must be specified as "background_audio".
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{
    "type": "background_audio"
}

Optional Properties

duration

  • Definition: The length of the background audio recording in seconds.
  • Possible values: A number seconds, decimals supported (i.e., 1.5)

  • Default: 0, meaning no set limit.

    Default duration behavior

    By default, there is no fixed limit on the duration of the background audio response. However, it is constrained by the overall duration of the trial. For example, if a trial includes both a background audio response and a choice response, the audio recording will stop as soon as the participant responds to the choice response. This may result in varying lengths of audio recordings across trials (of this setup).

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{
  "type": "background_audio",
  "duration": 1.5
}
In this code, the background audio response stops collecting data after 1500 milliseconds.

onset_detection

  • Definition: Whether to perform onset detection in this recording based on on real-time analysis of recording volume. If set to true, the audio response will record the time (in milliseconds) at which the participant first starts speaking (or making a loud noise).
  • Possible values: true or false
  • Default: false
  • See also: onset_sensitivity
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{
  "type": "background_audio",
  "onset_detection": true
}

onset_sensitivity

Dependencies

Requires onset_detection to be set to true.

  • Definition: The sensitivity of the onset detection feature. We don't recommend changing this setting unless there are hypothesis-driven reasons for your study to use a lower or higher sensitivity setting.
  • Possible values: an integer number between 1 and 99, with 1 being the least sensitive and 99 being the most sensitive.
  • Default: 50
  • See also: onset_detection
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{
  "type": "background_audio",
  "onset_detection": true,
  "onset_sensitivity": 60
}

parent

  • Definition: If specified, this response will inherit all properties from another defined response (aka, the parent), unless the same property is explicitly defined in this response.
  • Possible values: The name of another defined response.

Given a response named "bgaud1" defined as follows:

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{
  "type": "background_audio",
  "onset_detection": true,
  "volume_visualizer": true,
  "duration": 1.3
}

We can define a child response "bgaud2" that has its own duration property but is identical otherwise.

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{
  "type": "background_audio",
  "parent": "bgaud1",
  "duration": 2.5
}

stop_on_silence

  • Definition: Whether to automatically stop the recording when FindingFive detects that the participant has stopped speaking. The detection sensitivity can be tuned by the onset_sensitivity property (a larger value means more sensitive).

  • Possible values: true or false

    Property in tandem

    When this property is set to true, it automatically sets onset_detection to true as well and cannot be overridden.

  • Default: false

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{
  "type": "background_audio",
  "stop_on_silence": true
}

trim_leading_silence

  • Definition: Whether to automatically trim the leading silence of a recording. The sensitivity at which "silence" is determined can be tuned by the onset_sensitivity property (a larger value means more sensitive - that is, a tiny bit of noise will be considered as valid audio input and included in the output).

  • Possible values: true or false

    Property in tandem

    When this property is set to true, it automatically sets onset_detection to true as well and cannot be overridden.

  • Default: false

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{
  "type": "background_audio",
  "trim_leading_silence": true
}

volume_visualizer

  • Definition: Whether to display a volume bar indicating to the participants that their voices are being recorded.
  • Possible values: true, false

  • Default: false (i.e., not displaying the visualizer)

    Please inform your participants

    In the case that this property remains false, it is highly recommended that you inform participants that they are being recorded.

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{
  "type": "background_audio",
  "volume_visualizer": true
}

Recorded Data

  • value: The name of the sound file that is saved; this sound file is included in the downloadable zip archive containing your participant data.
  • rt: the onset time if onset_detection is turned on; empty otherwise