Siblings in Klipsch's Heritage series, so they share a family sound. It comes down to size, output and price.
| Area | Better | Why |
|---|
| Bass | A | Klipsch Heresy IV digs deeper - 48Hz against 58Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (99dB vs 99dB) - both want much the same power. |
| Headroom | evenly matched | Similar power handling (100W vs 100W). |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Cabinet | depends | Ported vs Sealed. Sealed is tighter and happier near a wall; ported digs lower but wants space behind it. |
| Expandability | depends | Klipsch Heresy IV: bi-amping; Klipsch Heresy III: bi-amping. |
| Price | B | Klipsch Heresy III is cheaper - $2,346 against $3,198, about 27% less. |
A Klipsch Heresy IV B Klipsch Heresy III
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Klipsch Heresy IV is ahead, but only on 1 of the measured areas, and it costs about 36% more. That is a lot of money for a narrow margin on paper - Klipsch Heresy III looks like the sensible buy unless something else about the Klipsch Heresy IV appeals to you. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 58Hz anyway, which makes the cheaper Klipsch Heresy III much easier to justify. Think about the whole system, not just the speakers: the roughly $852 saved by taking the cheaper pair would buy a subwoofer or a better amplifier, and either usually does more for the sound than the difference between these two.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.