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 | PSB P3 digs deeper - 57Hz against 64Hz. A subwoofer would even that out. |
| What you buy | depends | PSB Alpha iQ is a complete system - just add a source. PSB P3 also needs an amplifier: more money and another box, but you choose it. |
| Connections | depends | PSB Alpha iQ has Bluetooth, streaming, HDMI and phono built in. With PSB P3 that all comes from the amplifier you pair it with. |
| Upgrade path | depends | PSB P3 can be re-amped later and outlive several amplifiers; PSB Alpha iQ ages as one unit. |
| Size | depends | PSB P3 is easier to place; PSB Alpha iQ is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | A | PSB Alpha iQ: a sub output. |
| Price | B | PSB P3 is cheaper - $279 against $1,499, about 81% less; arguably a different class. Speakers only - an amplifier narrows that gap. |
A PSB Alpha iQ B PSB P3
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?
PSB Alpha iQ suits you if you want one box, ready to play, with nothing else to buy. PSB P3 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 64Hz anyway, so judge these on the other rows instead. Think about the whole system, not just the speakers: the roughly $1,220 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.