Headunit Pre Out Info

Bought a new headunit and it only has one pre out. I have my front speakers and tweeters amped and my 6x9s just run of the headunit. Since i put the headunit with one pre out in all the amped front speakers play is bass. Im guessing this is because the one pre out is for a sub.

Any way it can be changed to play the vocals and what not?

Probably not unless the crossover frequency can be switched by head-unit menu (unlikely)
What you can do is buy one or two of these:
http://www.ebay.co.uk/itm/180750216315?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
to turn your speakers outputs into pre-outs
one per pair of RCAs (Left and Right)

Does this mean the speakers will still benefit from the amp? Might just buy another headunit with more than one pre out tbh

I dare say your pre-out is actually a sub-out.

A new headunit would sort it out, or else 1 of those JL Audio signal amps that takes speaker outputs from a stereo and turns them into pre-outs...

What about these with the endss cut plugged rca to the speaker wire from the car?

All of the above
What headunit is it your using, some of the headunits have a rear/sub output, and as said depends if you can vary the frequency on the output.
Do you front speakers need to be amped?

Good speakers almost always benefit from being amped.
Buying a suitable headunit is the best outcome!!

Looks liek more money and hassle than its worth, Jus tgoing to go back and see if i can exchange it for one with more pre outs