The Heresy IV landed in 2019, the latest iteration of a lineage that stretches back to 1957. That original Heresy was Paul Klipsch's answer to the question nobody asked but everybody needed: what if you could get three-way speaker performance in a cabinet small enough to fit in a corner without declaring war on your living room? The current version keeps that practical footprint—just over two feet tall—but swaps out the old paper woofers and cloth surrounds for modern materials and a completely reimagined crossover. Klipsch built these in Hope, Arkansas, the way they've been built there for sixty years.
Here's the thing about 95dB sensitivity: it's not a trick, it's liberation. Most bookshelf speakers sit around 87dB, which means they're thirsty. A modest 50-watt amp struggles with them. The Heresy IV doesn't struggle. A 40-watt Class AB receiver—say a vintage Marantz or a modern Denon—will hit satisfying volumes in a normal room and actually sound like it has headroom to spare. That efficiency comes from the Tractrix horn-loaded midrange, the same engineering Klipsch's been refining since Paul's patent days. The horn isn't euphonic affectation; it's physics. It loads the midrange driver, lets it work at lower excursion, and delivers clarity you feel more than hear.
The 1.25-inch Titanium tweeter is new to the IV, and it's bright—not fatiguing, just honest. Vocals sit on top of everything else. Cymbals have texture. There's no politeness here. The dual 6.5-inch midwoofers handle the heavy lifting, and they do it with purpose. Bass doesn't go deep—you're looking at a 50Hz floor, not 35Hz—but what's there is controlled and propulsive. On rock records, the Heresys punch. On jazz, they let the rhythm section breathe.
The cabinet is a hardwood ported design, and yes, you hear it. These speakers are interactive with a room in ways that sealed boxes never are. Put them near a back wall and they'll boom. Float them slightly into the room, angle them right, and something clicks. They demand a little setup consideration, which turns out to be the whole point—you're supposed to think about where you put them.
The catch, and there's always a catch: the Heresy IV is a speaker for people who've heard horns before and have an opinion about them. If you're coming from sealed bookshelf speakers or panel designs, the midrange presentation can feel forward, almost aggressive. It's not fatiguing on good material, but on compressed streaming audio, poor recordings, or badly mastered records, they won't forgive. They're not dark or warm; they're unflinching. That's not a flaw if you know what you're buying into. It's a problem if you think any speaker should sound good with anything.
But on a decent pressing of Kind of Blue or Rumours or any Tom Petty record you grew up with, the Heresy IV makes modestly-powered amplifiers sound like they're worth keeping. They'll make an R-1050 feel like the smartest purchase you ever made.