Alternatively, only activate voting on comments when new users reach a certain karma threshold (does this exist already?), and only activate voting on stories when users reach a certain higher karma threshold.
To put it simply, if you want lots of karma points, don't bother responding to submissions (presumably in an attempt to help someone with a problem, or contribute to the conversation). Instead just find some "hot" controversial articles on some other tech related news sites and submit them instead. If this is true, then it should not be surprising that there is more "white noise" here at HackerNews, as this approach facilitates submitting stories instead of contributing to conversations.
My recommendation (if anyone cares), break karma points up into two separate values, one related to submitting articles/stories (which is valuable), and another related to submitting comments (which is also valuable). Then I would remove any reference of points from the system (make them hidden from users) as to remove any desire to "game the system" for points. This would result in a system where points do not influence how people contribute to the community.