A generation apart: Audio-Technica AT-SP3X is the newer design, against a 2017 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | A | Audio-Technica AT-SP3X digs deeper - 55Hz against 65Hz. |
| Built-in power | evenly matched | Similar onboard amplification (30W vs 30W RMS). |
| Connections | evenly matched | The same set of inputs and streaming options. |
| Size | depends | Audioengine A2+ Wireless is easier to place; Audio-Technica AT-SP3X is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | Audioengine A2+ Wireless: a sub output. |
| Price | evenly matched | Much the same money ($269 vs $269 a pair). |
A Audio-Technica AT-SP3X B Audioengine A2+ Wireless
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and your own room settle it. 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, Audio-Technica AT-SP3X has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Audioengine A2+ Wireless 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.