Its purpose is to deliver the same power across a wide range of impedences

and input voltages. So in short, any subwoofer with impedences between 1.5 and 4 ohms, will recieve the same power. Also, any differences in sound quality will be negligible, at best.

Does higher ohms mean better sound?

So yes, higher the ohms better the sound experience; that is dependent on if you're using the appropriate amp to provide the required power, 100 ohms headphones plugged into a laptop will not get you the experience you expected, as most laptops support an impedance of only up to 32 ohms.

Do 4 ohm speakers sound better?

The answer generally is yes but it mostly depends on your ability to drive 4 ohms speakers properly! Also, no home sound system is immune to impedance issues. ... A higher ohm speaker with higher sensitivity will be as effective as a lower ohm speaker.