Analysis menu. MOTU 828es

ANALYSIS MENU

Choose the desired form of audio analysis from

the Analysis menu (Figure 10-1). For details on

each analysis pane, see the following sections of this guide.

LEFT/RIGHT INPUT

Choose the desired channel(s) you wish to scope from the Left Input and Right Input menus

(Figure 10-1). These menus display the To

Computer channels configured in the MOTU Pro

Audio Control web app. The number of channels shown is controlled by the From device to

computer setting in the Device tab. For example, if

18 channels are specified, you’ll see 18 channels in the Left/Right Input menus. Use the Routing tab to map desired audio sources (listed across the top of the grid) to the To Computer audio channels, as

demonstrated in Figure 8-7 on page 68.

Y-axis labels for FFT display

Figure 10-2: The ‘From device to computer’ setting determines how many channels you see in the Left Input and Right Input menus.

FFT AND SPECTROGRAM DISPLAY

The FFT analysis pane displays a real-time Fast

Fourier Transform (FFT) frequency measurement and spectrogram “waterfall”, as shown in

Figure 10-3.

Spectrogram

The spectrogram scrolls from top to bottom, where the top edge of the display represents what you are hearing “now”. Color represents amplitude along the left/right frequency spectrum. The amplitude color scale runs from black (silence) to red (full scale) as follows:

Silence

Black Blue Green Yellow Orange

Figure 10-4: Spectrogram color-to-amplitude spectrum.

Full scale

Red

FFT curve

View controls

Horizontal controls

Vertical controls

Spectrogram controls

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Figure 10-3: FFT and Spectrogram display.

Grow handle

M O T U A U D I O T O O L S

View controls

You can show and hide the FFT display and spectrogram as desired using the View controls

(Figure 10-5).

Pause button

View menu

Display options

Figure 10-5:

FFT view controls.

View menu

This menu provides various options for displaying the two input channels.

View menu setting

What it does

Left Displays the left channel only.

Right Displays the right channel only.

Split Screen H

Split Screen V

Shared

Max

Subtract L - R

Shows both channels side by side, with the screen split horizontally.

Shows both channels side by side, with the screen split vertically.

Displays both FFTs (left is green and right is red), and the spectrogram waterfall shows the maximum level of either the left or right channel (whichever is greater).

The FFT and spectrogram shows the maximum level of either the left or right channel.

Subtracts the right channel from the left channel and displays the results.

Logarithmic or Linear X-Axis Scale

The x-axis defaults to a logarithmic scale, but it can be changed to a linear scale if desired. In the

View controls (Figure 10-5), click Logarithmic to

access the x-axis scale options menu. With a linear scale selected, frequency is constant, but the width of each octave along the x-axis is different. With a logarithmic scale selected, octaves are displayed with a constant width, but frequency is displayed logarithmically within each octave.

Axes display

The Axes control (Figure 10-5) sets the opacity of

the grid displayed in the graph, from 100% (fully visible) down to 0% (fully hidden).

Pausing the display

The Pause button in the upper right corner of the

View section (Figure 10-5) allows you to freeze the

display at any time. To resume, click the button again.

Horizontal controls (frequency axis)

The Horizontal controls (Figure 10-6) configure

the value range of the x-axis (frequency). Click and drag the values up or down to set them, or double-click to return to the default value.

Figure 10-6: The Horizontal controls.

Horizontal controls menu

There are two modes for the controls: Zoom/Offset and Min/Max. To change the mode, use the

Horizontal control menu (Figure 10-6).

In Zoom/Offset mode, Zoom sets the display zoom from 1x to 100x, where the number represents the zoom factor relative to the entire frequency range.

For example, when the horizontal zoom value is

1x, the entire frequency range from 10 to 24000

Hertz is displayed; when the horizontal zoom value is 2x, one half of the entire frequency range is displayed. Pos determines which frequency is displayed at the center of the graph.

In Min/Max mode, Min and Max set the lowest and highest displayed frequencies (in Hertz).

Vertical controls (amplitude axis)

The Vertical controls (Figure 10-7) operate

similarly to the Horizontal controls, except that they configure the y-axis (amplitude).

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