What are tweeter speakers?

The tweeter and midrange speakers are not working on one of my Akai Speakers?

• Okay, i just recently set up my vintage Akai speakers that have a mid range tweeter and a subwoofer built in with a old receiver I found. But when i went to turn em on, one of the speakers was only playing sound through the subwoofer. But the other one is completely fine. They were just working 4 or so months ago as well. And the part that stumps me the most is when i went to adjust the little knobs for the mid and high range speakers. They were all like, locked and i had to almost force them to move. Any input would be great. Theyre really nice sounding speakers and i just fixed the surrounds on them so i would like to get them working.

• Answer:

  So your speakers have some built in trims on them? And they don't work? You could try contact cleaner, maybe. Perhaps the high freq section is blown on one channel. That can happen. Try asking this in a DIY speaker forum, such as over at avsforum.com. There's people more experienced in speakers that I am in those places.