I'm a musician, avocationally. I have a pair of Etymotics earplugs that have much flatter frequency response than the foam ones. (Well relatively. Most frequency response graphs of things one puts in or over ones ears don't really look all that "flat." <http://www.etymotic.com/er20.html> No, I don't work for them or know them.) I wear these as a means to control volume in situations where I wouldn't otherwise be able to, but still need to hear things clearly, and they work. As a result, I've had occasion to answer questions about them in public places like conferences in the Bay Area, and I've noted a few condescending and smarmy responses, as well as a "I don't know what that is."

(EDIT: Seems like you're pattern-matching me a bit, based on "stuff you saw on the Internet." However very big changes in frequency response can make big, measurable and predictable differences, even in how well one can understand speech. I've had occasion to undo naive sound-person's adjustments to bring out bass and treble, but as most speech information is carried in the "midrange" frequencies, this makes announcers less comprehensible.)

(Fellow Etymotic user here)