Different kinds of product: one is active with its amplifier built in, the other passive and needs one. Judge them on how you want to own the system, not just the specs.
| Area | Better | Why |
|---|
| Bass | B | KEF LSX digs deeper - 59Hz against 79Hz. |
| What you buy | depends | KEF LSX is a complete system - just add a source. KEF LS50 Meta also needs an amplifier: more money and another box, but you choose it. |
| Connections | depends | KEF LSX has Bluetooth, Wi-Fi and streaming built in. With KEF LS50 Meta that all comes from the amplifier you pair it with. |
| Upgrade path | depends | KEF LS50 Meta can be re-amped later and outlive several amplifiers; KEF LSX ages as one unit. |
| Size | depends | KEF LSX is easier to place; KEF LS50 Meta is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | KEF LSX: a sub output. |
| Price | B | KEF LSX is cheaper - $1,250 against $1,600, about 22% less. And that is the whole system. |
A KEF LS50 Meta B KEF LSX
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?
KEF LSX suits you if you want one box, ready to play, with nothing else to buy. KEF LS50 Meta suits you if you already have an amplifier, want to choose the electronics, or expect to upgrade in stages. Neither is the better speaker in the abstract. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 79Hz anyway, so judge these on the other rows instead. In a large or open-plan room, KEF LS50 Meta has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, KEF LSX 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.