These sit in different price classes - KEF LS LUXE costs roughly 7.3x what Cambridge Audio L R S 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 | KEF LS LUXE digs deeper - 42Hz against 60Hz. |
| Built-in power | A | KEF LS LUXE has the bigger amplifier (380W vs 100W RMS). |
| Connections | B | KEF LS LUXE adds HDMI; Cambridge Audio L R S adds Bluetooth and digital inputs. |
| Size | depends | Cambridge Audio L R S is easier to place; KEF LS LUXE is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | Cambridge Audio L R S: a sub output. |
| Price | B | Cambridge Audio L R S is cheaper - $549 against $4,000, about 86% less; arguably a different class. |
A KEF LS LUXE B Cambridge Audio L R S
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and your own room settle it. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 60Hz anyway, which makes the cheaper Cambridge Audio L R S much easier to justify. In a large or open-plan room, KEF LS LUXE has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Cambridge Audio L R S 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.