Outer Hair Cells (OHCs) provide modulation. But in what way?

[rcrowder]

To quote Dr. Nick Clarke;

Dynamic compression with either long or short time constants has, of course, long been a feature of modern hearing aid design but the compression observed at the level of the BM in animal studies is qualitatively different. BM compression has no obvious time constant. It is virtually instantaneous and similar in nature to ‘clipping’ but without the unwanted distortion products. When the OHCs fail for whatever reason, this compression disappears along with the sensitivity to quiet sounds.
http://bioaid.org.uk/project.html

Does this relate to ideas of frequency selection, efferent attention aspects from the Thalamas?