These sit in different price classes - Klipsch R-51PM costs roughly 3x what Audioengine A1 Wireless 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 | B | Audioengine A1 Wireless digs deeper - 65Hz against 68Hz. A subwoofer would even that out. |
| Built-in power | A | Klipsch R-51PM has the bigger amplifier (120W vs 30W RMS). |
| Connections | A | Klipsch R-51PM adds phono and digital inputs. |
| Size | depends | Audioengine A1 Wireless 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; Audioengine A1 Wireless: a sub output. |
| Price | B | Audioengine A1 Wireless is cheaper - $199 against $599, about 67% less; arguably a different class. |
A Klipsch R-51PM B Audioengine A1 Wireless
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 R-51PM is ahead, but only on 1 of the measured areas, and it costs about 3x the price. That is a lot of money for a narrow margin on paper - Audioengine A1 Wireless looks like the sensible buy unless something else about the Klipsch R-51PM appeals to you. 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, Audioengine A1 Wireless is the easier speaker to get right. Think about the whole system, not just the speakers: the roughly $400 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.