A generation apart: Kanto YU4 is the newer design, against a 2011 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass |
B |
Audioengine A5+N digs deeper - 50Hz against 60Hz. |
| Built-in power |
A |
Kanto YU4 has the bigger amplifier (70W vs 50W RMS). |
| Connections |
A |
Kanto YU4 adds Bluetooth, phono and digital inputs. |
| Size |
depends |
Kanto YU4 is easier to place; Audioengine A5+N is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability |
depends |
Kanto YU4: a sub output; Audioengine A5+N: a sub output. |
| Price |
evenly matched |
Much the same money ($450 vs $469 a pair). |
A Kanto YU4
B Audioengine A5+N
depends neither is better in the abstract - it turns on your room, placement 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?
Kanto YU4 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 60Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Audioengine A5+N has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Kanto YU4 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.