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 | ELAC Debut 2.0 B6.2 digs deeper - 44Hz against 48Hz. A subwoofer would even that out. |
| What you buy | depends | ELAC Debut ConneX DCB61 is a complete system - just add a source. ELAC Debut 2.0 B6.2 also needs an amplifier: more money and another box, but you choose it. |
| Connections | depends | ELAC Debut ConneX DCB61 has HDMI built in. With ELAC Debut 2.0 B6.2 that all comes from the amplifier you pair it with. |
| Upgrade path | depends | ELAC Debut 2.0 B6.2 can be re-amped later and outlive several amplifiers; ELAC Debut ConneX DCB61 ages as one unit. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Expandability | depends | Neither adds bi-amping, a sub output or height drivers. ELAC Debut 2.0 B6.2 sits in a wider range (11 models), so a matched surround system is easier later. |
| Price | B | ELAC Debut 2.0 B6.2 is cheaper - $400 against $899, about 56% less; arguably a different class. Speakers only - an amplifier narrows that gap. |
A ELAC Debut ConneX DCB61 B ELAC Debut 2.0 B6.2
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?
ELAC Debut ConneX DCB61 suits you if you want one box, ready to play, with nothing else to buy. ELAC Debut 2.0 B6.2 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. Think about the whole system, not just the speakers: the roughly $499 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.