These sit in different price classes - Klipsch R-51PM costs roughly 2x what Jamo S 801 PM does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass | A | Klipsch R-51PM digs deeper - 68Hz against 76Hz. A subwoofer would even that out. |
| Built-in power | A | Klipsch R-51PM has the bigger amplifier (120W vs 50W RMS). |
| Connections | A | Klipsch R-51PM adds phono. |
| Size | depends | Jamo S 801 PM is easier to place; Klipsch R-51PM is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Klipsch R-51PM: a sub output; Jamo S 801 PM: a sub output. |
| Price | B | Jamo S 801 PM is cheaper - $300 against $599, about 50% less; arguably a different class. |
A Klipsch R-51PM B Jamo S 801 PM
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?
The usual trade-off: Klipsch R-51PM measures better, Jamo S 801 PM costs about about 100% more% less. Whether that gap is worth the money is the call only you can make - and in a normal room it is often smaller than the numbers suggest. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 76Hz anyway, which makes the cheaper Jamo S 801 PM much easier to justify. In a large or open-plan room, Klipsch R-51PM has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Jamo S 801 PM is the easier speaker to get right.
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.