Persistence, Using the xy plot – MOTU 828x 28x30 Audio Interface with ThunderTechnology User Manual
Page 106

C U E M I X F X
106
Persistence
The
Persistence
controls (Figure 9-47) affect the
appearance of data from when it is first displayed 
until it disappears from the grid.
Figure 9-47: The Persistence controls.
Length
Length
(Figure 9-47) sets the number of recent
samples to show on the plot. For example, when 
Length is set to 10,000, the 10,000 most recent 
samples are shown. 
Decay
The brightness (in Grayscale mode) or hue (in 
Color mode) of each sample on the plot is 
determined by a linear scale, with the most recent 
sample displayed at the maximum value and the 
oldest sample displayed at the minimum value. 
Decay
(Figure 9-47 on page 106) determines the
brightness or hue of the minimum value. When 
Decay is zero, the oldest sample is black. When 
Decay is +1.000, the oldest sample is fully opaque 
(in Grayscale mode) or red (in Color mode). 
Warp
Warp
(Figure 9-47) determines the position of data
points after they are first drawn. When warp is 
zero, data points remain in the same position. 
When warp is positive, they contract towards the 
origin (center of the grid). When warp is negative, 
they expand away from the origin. The further the 
warp value is from zero, the greater the effect. 
Using the X-Y Plot
The X-Y Plot helps you “see” the width of the stereo 
field of a mix. It also helps you determine if a mix 
has issues with polarity, as follows: 
If a stereo signal is out of phase, it is not mono 
compatible because it can cancel itself out, either 
partially or nearly completely, when collapsed to 
mono.
Figure 9-48: Checking polarity in a stereo signal with the X-Y Plot.
Activity on the X-Y Plot
What it indicates
Signal activity occurs mostly 
along the x = y axis (lower left 
to upper right) and the Corre-
lation meter reading is high
Left and right channels are pre-
dominantly in polarity (the ste-
reo field is relatively narrow)
Signal activity occurs mostly 
along the y = -x axis (upper left 
to lower right) and the Corre-
lation meter reading is low 
(near -1)
Left and right channels are pre-
dominantly out of polarity (not 
in phase)
Signal activity occurs in a 
seemingly random fashion 
throughout the grid
No phase relationship exists 
(i.e. it is probably a wide stereo 
field)
In polarity
Out of polarity
No polarity
