Siblings in ELAC's Vertex Series I series, so they share a family sound. It comes down to size, output and price.
| Area | Better | Why |
|---|
| Bass | evenly matched | Much the same reach (45Hz vs 45Hz). |
| Amplifier needs | B | ELAC Vertex Series I IW V61 W is more sensitive (90dB vs 87dB), so it goes louder on the same amplifier. |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Type | depends | A Passive Center Channel against a Passive In-wall - a different job rather than a better one. |
| Price | A | ELAC Vertex Series I IW VC51 W is cheaper - $429 against $698, about 39% less; arguably a different class. |
A ELAC Vertex Series I IW VC51 W B ELAC Vertex Series I IW V61 W
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 Vertex Series I IW V61 W is ahead, but only on 1 of the measured areas, and it costs about 63% more. That is a lot of money for a narrow margin on paper - ELAC Vertex Series I IW VC51 W looks like the sensible buy unless something else about the ELAC Vertex Series I IW V61 W appeals to you. If your amplifier is modest, vintage or valve-based, ELAC Vertex Series I IW V61 W is the safer partner - the other will want more current or more watts to sound its best. Think about the whole system, not just the speakers: the roughly $269 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.