X-tal Lock

Sony technology which employs a quartz crystal to generate a reference frequency from which all others are derived. Assures accurate frequency selection.

Xmax

The distance a speaker cone can travel before the magnet loses control over the voice coil.

XM Satellite Ready

Signifies that the head-unit is completely compatible with XM Satellite Radio, a satellite based radio service.

X and Y axis

In a graph or chart showing the relationship of one acoustical phenomenon or measurement relative to another, it is common to plot the relationship on a chart with intersecting vertical and horizontal axis (X and Y) that graphically shows the interaction between two or more elements, such as frequency and power in a given situation.