Here's a few
comparative graphs that may give a little wider understanding. As far as we're concerned here, it's the shapes of the plotted curves that matter, not the force values or the application (car) that they were taken from.
"Progressive" damping (purple lines on page 2) - will make up for poorish body control damping with a harsh ride. Linear (which as shown in red is actually mildly digressive) at least gives you a bit more body control.
The slope of a line at any given point is another indication of how much damping exists, separate from the vertical axis force value.
Pete - Bob Bolles has to be talking from a pure race car perspective. Just about every other reference I've seen that even mentions high vs low speed damping talks about the low speed range of interest being about 3 ips. Even 50% critical damping (for grip/handling) at 10 ips sounds just plain harsh from the point of view of anything reasonably streetable. On the linked graphs, 10 ips is about 70% of the way out to the maximum horizontal scale of 35 cm/sec and long after the high speed circuits have opened.
Norm