I just installed some brand new pioneer speakers in the rear, and when they play, they sound really scrachy and it sounds as though I have it turned up really load and it’s too much for the speaker. Now I don’t have an amp or anything, it’s just hooked up to an old Alpine tape deck cause my Pioneer CD player got stolen 
Now, what could be causing this problem, I checked to make sure that the wires were hooked up right, and they are brand new. Any help would be great, thanks.
Well first ask ur self, what am I trying to accomplish…
If I was u, I would find out if the speakers are bad.
Simply put the + & - connectors for the spaekers to any amplifier or receiver to see if it puts out proper sound, or u can discover if the speaker is messed up.
If its clear sound then obviously it is not something wrong with the speakers.
Then assume ur old alpine deck is funny, or either wires are not setup correctly, still stuckk???
Try hooking up some other speakers to ur alpine, and see if they sound shitty…
Still stuck? Speakers ok, but deck still making noise, maybe its a the wiring?
Well then go steraight to the back of ur deck, find the wires for the speakers, and connect ur speaker up to the deck, this way you will know for sure, there is no fucked up wiring somewhere touching something funny, u’ll be able to find out whats wrong.
All you gota ask your self is what ur trying to accomplish, and reall really think about what is worng and what might be causing it.