Siblings in Cambridge Audio's SX series, so they share a family sound. It comes down to size, output and price.
| Area | Better | Why |
|---|
| Bass | B | Cambridge SX-50 digs deeper - 50Hz against 65Hz. |
| Amplifier needs | B | Cambridge SX-50 is more sensitive (90dB vs 85dB), so it goes louder on the same amplifier. |
| Headroom | evenly matched | Similar power handling (100W vs 100W). |
| Size | depends | Cambridge SX-50 is easier to place; Cambridge Audio SX-70 is bigger, which usually goes with fuller bass. Your room decides. |
| Type | depends | A Passive Center Channel against a Passive Bookshelf - a different job rather than a better one. |
| Cabinet | depends | Sealed vs Ported. Sealed is tighter and happier near a wall; ported digs lower but wants space behind it. |
| Price | evenly matched | Much the same money ($189 vs $199 a pair). |
A Cambridge Audio SX-70 B Cambridge SX-50
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?
Cambridge SX-50 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 65Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Cambridge Audio SX-70 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Cambridge SX-50 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.