http://community.crutchfield.com/blogs/av_tips/archive/2008/12/10/better-car-audio-tip-2-reduce-road-noise.aspxHave you ever noticed how your car audio system sounds really good at 25 mph, but gets a little harsh when you hit 60? Road noise tends to mask the lower frequencies first, so your system sounds overly bright when you turn it up at highway speeds. DynamatenCommunityServer 2008.5 SP2 (Debug Build: 40407.4157)