Aura Help Center

History

The History meter displays an audio signal across a real-time timeline

The History meter is constructed from any number of “modules”, and the modules can contain any number of traces to display a signal. Many different traces are included in this meter, such as Spectrogram, Waveform, Power Difference, and others. Overlays can be added to the entire meter or to individual modules to help aligning values visually.

Crosshairs

Click and drag in the meter to display location details.
  • The first line is the time in the past in seconds.
  • The following lines are the values of the traces included in the module at that position.
Hold down option while dragging to see the difference between where the cursor was clicked and the current position

Controls

Hover the mouse over the meter to reveal the control bar.
Show the meter configuration popover
Show the traces configuration popover
Pause the meter and enable scrollback
Run the meter
Reset the meter values

Scrollback

When the meter is paused, you can scroll back to see previous history.
  • The maximum scrollback is about 90 seconds.
  • Clicking the play button will return to the most current audio and run the meter.

Meter Configuration

Click the name to reveal settings for that section.

General

  1. The speed of the meter. The speed might affect the number of analyzed samples per second in a trace.
  2. The direction of the timeline.
  3. The background color.
  4. Select to show the grid.
  5. The color of the grid.
  6. The color of the crosshairs.

Rulers

  1. Click to select a ruler to configure
  2. Select to show the ruler
  3. Select the size of the ruler text
  4. Select the direction the text will be written
  5. Choose a color for the ruler text
The values shown on the ruler will depend on the orientation of the meter.

Overlay

  1. Select to show the overlay that covers the entire meter.
  2. Select to display the overlay colors as high → mid → low → mid → high
  3. Rotate the overlay 90° counterclockwise
  4. Flip the overlay vertically or horizontally
  5. Select the color set to use
  6. Set the intensity/opacity
  7. Set the position of the transition between the low color and the mid color
  8. Set the position of the transition between the mid color and the high color

Traces

Traces compute and display the analysis results of the audio.
  • All traces can be configured independently or as a group.
  • One or more traces can be visible at the same time - even of different kinds.
  • Trace values can be exported to files as text or images.

Correlation History

  • Takes two discrete audio inputs with an optional delay on one input
  • Compares the positive and negative samples and calculates a value
  • Displays the calculated value over time
Useful For...
Detecting phase issues between channels, determining stereo “spread”.

Leq History

  • Given one or more audio inputs, accumulates audio over time
  • Applies a filter and combines them into a single audio signal
  • Calculates a value from the set of samples
  • Calculates the average since the meter was started or reset
  • Displays the average value over time
Useful For...
Determining the ”energy” of audio over time.

Level History

  • Similar to combination of a Waveform and a Bar-style level meter
  • Given one or more audio inputs, combines them into a single audio signal
  • Applies gain to the signal and calculates a value
  • Applies responses to make the values easier to watch over time
Useful For...
Visualizing standard calculations over time.

Loudness History

  • Given specific channel inputs, applies a specialized algorithm to determine a value
  • The algorithm in use and the response depends on the selected measurement
  • Results are in LU/LUFS and are displayed on a static scale
Useful For...
Determining the Program Loudness, a standard across the industry.

Power Difference History

  • Takes two discrete audio inputs with an optional delay on one input
  • Compares the power difference between the channels and calculates a value
  • Displays the calculated value over time
Useful For...
Determining balance issues in stereo audio.

Spectrogram

  • Given one or more audio inputs, combines them into a single audio signal
  • Using an FFT, converts the audio signal into its frequency components
  • Converts the magnitude (or level) of the frequency components to colors
  • Displays the colors over time to make frequency changes easy to see
Useful For...
Visualizing frequency responses, harmonic series, acoustic resonances, and more.

Waveform

  • Given one or more audio inputs, combines them into a single audio signal
  • Applies gain to the signal and calculates positive and negative values
  • Displays the calculated values over time
  • Can zoom and scale to focus on low-level signals
Useful For...
Visualizing levels similar to a DAW, determining low-level artifacts.

Modules & Traces Configuration

The area on the left lists the traces in the meter.
The area on the right allows configuration of the selected traces. Click the name to reveal settings for that section.

Module & Trace List

  1. The list of modules and traces in display order. Press return to edit the name.
  2. Select a module or trace to add or duplicate.
  3. Click to delete the selected items.
  4. Export the values of the selected trace to a text or image file.

Module

General

  1. The background color of the module. Click the button to clear the background color.

Overlay

  1. Select to show the overlay
  2. Select to display the overlay colors as high → mid → low → mid → high
  3. Rotate the overlay 90° counterclockwise
  4. Flip the overlay vertically or horizontally
  5. Select the color set to use
  6. Set the intensity/opacity
  7. Set the position of the transition between the low color and the mid color
  8. Set the position of the transition between the mid color and the high color

Correlation History

Source

  1. Select the channel to be used for source X.
  2. Select the channel to be used for source Y.
  3. Set the amount of time difference to add to source Y. Negative values are allowed.

Display

  1. Select the thickness of the stroked line.
  2. Select the base color.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

LEQ History

Source

  1. Select the channels to use for the input
  2. Set the calibration for the microphone, if necessary.
  3. Select the filter to apply for measurement
  4. Set the length of the audio to be analyzed at once
    • Extra Short: 250ms
    • Short: 500ms
    • Medium: 1s
    • Long: 3s
    • Extra Long: 10s
  5. Set the gain to be applied

Display

  1. Select the base color.
  2. Select the fill to draw between the stroked line and the zero line.
    • None: no fill is drawn.
    • Solid: the color of the trace.
    • Translucent: the color of the trace with half the opacity.
    • Faded: the color gradiated from transparent at the anchor to opaque at the top magnitude.
  3. Select the thickness of the stroked line.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

Level History

Source

  1. The audio inputs to combine.
  2. The method used to combine the channels.
    • Sum: adds the samples together
    • Difference: even numbered channels are subtracted from odd numbered channels
    • Average: the samples are added together and divided by the number of channels
    • Average Difference: even numbered channels are subtracted from odd numbered channels and the result is divided by the number of channels
  3. The amount of gain to be added to the combined result.
  4. The mathematical algorithm to use to quantify the set of audio samples.
    • Peak: The maximum magnitude
    • TruePeak: The maximum magnitude after a high-definition upsampling
    • RMS: The root-mean-square
    • AES-17: The root-mean-square value + 3dB
    • Average: The mean
  5. The response rise and fall time.
  6.   Rise Time Hold Time Fall Time
    Digital 9.5dB in 1.7ms none 20dB in 850ms
    PPM Type I 9.5dB in 1.7ms none 20dB in 1.7s
    PPM Type II 9.5dB in 1.7ms 100ms 24dB in 2.8s
    VU 40dB in 300ms none 40dB in 300ms
    Nordic 14dB in 5ms none 20dB in 1.5s
    BBC/EBU 14dB in 5ms none 24dB in 2.85s
    Peak Hold (Short) immediate 0.7s 60dB in 300ms
    Peak Hold (Long) immediate 2.0s 60dB in 300ms

Display

  1. Select the base color.
  2. Select the fill to draw between the stroked line and the zero line.
    • None: no fill is drawn.
    • Solid: the color of the trace.
    • Translucent: the color of the trace with half the opacity.
    • Faded: the color gradiated from transparent at the anchor to opaque at the top magnitude.
  3. Select the thickness of the stroked line.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

Loudness History

Source

  1. The audio input that contains the left channel content.
  2. The audio input that contains the right channel content.
  3. The audio input that contains the center channel content.
  4. The audio input that contains the left surround channel content.
  5. The audio input that contains the right surround channel content.
  6. The scale to be used
    • LU +9: Standard program loudness scale range from -18 LU to +9 LU
    • LU +18: Standard program loudness scale range from -36 LU to +18 LU
  7. The unscaled value that will appear at 0 on the scaled meter. -23 LUFS is standard.
  8. The time scale for the program loudness measurement
    • Momentary: a non-gated time window of 0.4s
    • Short-Term: a non-gated time window of 3.0s
    • Integrated: the gated accumulated value

Display

  1. Select the base color.
  2. Select the fill to draw between the stroked line and the zero line.
    • None: no fill is drawn.
    • Solid: the color of the trace.
    • Translucent: the color of the trace with half the opacity.
    • Faded: the color gradiated from transparent at the anchor to opaque at the top magnitude.
  3. Select the thickness of the stroked line.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

Power Difference History

Source

  1. Select the channel to be used for source X.
  2. Select the channel to be used for source Y.
  3. Set the amount of time difference to add to source Y. Negative values are allowed.

Display

  1. Select the color.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

Spectrogram

Source

  1. The audio inputs to combine.
  2. The method used to combine the channels.
    • Sum: adds the samples together
    • Difference: even numbered channels are subtracted from odd numbered channels
    • Average: the samples are added together and divided by the number of channels
    • Average Difference: even numbered channels are subtracted from odd numbered channels and the result is divided by the number of channels
  3. The amount of gain to be added to the combined result.

Analysis

  1. Select the windowing function to apply to the audio before analysis.
  2. Select the number of samples to gather for analysis.
  3. Select the method used to average the results.

Display

  1. The set of colors to use for displaying the magnitudes.
  2. The “transparency” of the gradient.
  3. The minimum frequency that will be displayed in the trace.
  4. The maximum frequency that will be displayed in the trace.

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.

Waveform

Source

  1. The audio inputs to combine.
  2. The method used to combine the channels.
    • Sum: adds the samples together
    • Difference: even numbered channels are subtracted from odd numbered channels
    • Average: the samples are added together and divided by the number of channels
    • Average Difference: even numbered channels are subtracted from odd numbered channels and the result is divided by the number of channels
  3. The amount of gain to be added to the combined result.
  4. The mathematical algorithm to use to quantify the set of audio samples.
    • Peak: The maximum magnitude
    • RMS: The root-mean-square
    • AES-17: The root-mean-square value + 3dB
    • Average: The mean

Display

  1. The drawing style
    • Full Wave: positive and negative values are drawn above and below a zero line
    • Rectified: magnitudes are drawn above a zero line
  2. The values used to determine the height
    • Linear: scalar values
    • Logarithmic: decibel values
  3. The color of the waveform
  4. The amount of value zoom

Control

  1. Select to run the trace. Deselect to pause.
  2. Select to hide the trace.