i was thinkin about buildin myself a 4x10 bass cab for a school project. any speaker suggestions?
It is probably worth your while giving more details. What sound do you want? What amp will you use ? What is your budget?

How technical do you want to get?

If you want to build a reflex (ported ) cab then that is more difficult than a sealed cab. Design is more critical and more complex. Ported cabs need speakers with a larger magnet than closed cabs. The figure that tells you if a magnet is big enough is Qts in the specs, the bigger the magnet the smaller Qts is. You need Qts below 0.4 for a reflex and 0.7 for a sealed box.

Eminence are OK, go for at least a beta. If you can afford it the pro series have cast chassis which make the speaker more reliable long term. The Jensens I have seen have tiny magnets and I wouldn't have used them but maybe they make something better.

If you send me links I can look at the specs for you and indicate whether the speakers are likely to sound good.