Siblings in Fluance's Ai 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 (32Hz vs 30Hz). |
| Built-in power | B | Fluance Ai81 has the bigger amplifier (150W vs 120W RMS). |
| Connections | evenly matched | The same set of inputs and streaming options. |
| Size | depends | Fluance Ai61 is easier to place; Fluance Ai81 is bigger, which usually goes with fuller bass. Your room decides. |
| Type | depends | A Powered Bookshelf against a Powered Floor-standing - a different job rather than a better one. |
| Expandability | depends | Fluance Ai61: a sub output; Fluance Ai81: a sub output. |
| Price | A | Fluance Ai61 is cheaper - $299 against $499, about 40% less; arguably a different class. |
A Fluance Ai61 B Fluance Ai81
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?
Fluance Ai81 is ahead, but only on 1 of the measured areas, and it costs about 67% more. That is a lot of money for a narrow margin on paper - Fluance Ai61 looks like the sensible buy unless something else about the Fluance Ai81 appeals to you. In a large or open-plan room, Fluance Ai81 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Fluance Ai61 is the easier speaker to get right. Think about the whole system, not just the speakers: the roughly $200 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.