8.2. Characteristics of Gradient Arrays
Pattern Options
For a given gradient pair, the pattern can be varied by changing the rear-element delay.
Available patterns are similar to those of microphones: cardioid, hypercardioid (various types), and figure-8.
Figure 24 and Figure 25 show four pattern options for the back-to-back Xsub pair from the example above.
Element Spacing, Output, and Bandwidth
When constructing a gradient pair, it is important to understand the role of element spacing.
By “element spacing”, we mean the distance between front and rear loudspeaker cones.
Larger element spacing increases subbass output, but decreases maximum operating frequency. Smaller element spacing decreases output but increases maximum operating frequency.
In our example, the element spacing is 62 inches (157 cm), which gives a maximum operating frequency of approximately 90 Hz. The pattern deteriorates rapidly above the high-frequency limit, as Figure 26 shows.
