Odd behavior with Shift-Alt key combo
I need to create 2 concentric arcs, mimicking sound waves...
I found this example (Number 2)
I'd really want to use this method, but when I hold Alt and Shift on the second step, it starts creating a circle on the edge of the low-right quadrant, NOT CENTERED. If I move the mouse to another quadrant (as defined by the guides) it starts making the circle there, with the sides touching the guides.
Mouse over the circle and hold down ALT. The cursor will display a little minus sign, to show that the next shape you create will be subtracted from the top shape.
As you begin clicking and dragging with the Ellipse Tool to create the inner circle, while still holding down Alt, also hold down Shift, as you click and drag. This will subtract the top shape from the bottom.
I did turn off the Snap, but it made no difference.
Any help would be appreciated.