I've owned Klipsch Heresys, and I currently own Klipschorns. My experience with the Heresys did not match that of your friend. I had two different pairs come into my possession, and frankly I couldn't get rid of them fast enough. They just sounded thin and harsh. No matter , they're gone.
The Klipschorns I acquired one at a time around 1999-2000. (they're fairly early models so were originally sold separately during the monophonic era) They sat in storage in my garage until we added on to the house and I finally had a room large enough to use them. I started using them in 2009. They're an entirely different animal compared to the Heresys. To the question you posed, to me they sound fine on vocals. Just last week I was listening to Suzanne Vega and Ricki Lee Jones....... sounded good. They have a clean clear effortless sound quality to them, and of course fill a room nicely. Ironically, for all their size they don't have tons of bass down deep. Many swear you have to use tube power for Klipschorns, but I've been happy using tubes or solid state.
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