If this is an AV receiver did you run the set up?
That lets the receiver know what speakers you have connected so it can send audio where it should. If the receiver thinks you have a center channel and you don't it will send dialogue to the speaker you don't have.
When you set the receiver it also balances the levels of the speakers. That will tell you if they are all working.
The center speaker is on all the time and the front left and right almost all the time.
The surround speakers only come on when they are supposed to which can be almost never depending on the source.
Make sure your source is set correctly to output in surround and that you have chosen the correct surround sound mode on the Sony for that source.
Rear speakers don't usually play music or talking, only background sounds and such for movies. What are you trying to use them with, games? How are they hooked up. Surround is a tricky thing.
If this is an AV receiver did you run the set up?
That lets the receiver know what speakers you have connected so it can send audio where it should. If the receiver thinks you have a center channel and you don't it will send dialogue to the speaker you don't have.
When you set the receiver it also balances the levels of the speakers. That will tell you if they are all working.
The center speaker is on all the time and the front left and right almost all the time.
The surround speakers only come on when they are supposed to which can be almost never depending on the source.
Make sure your source is set correctly to output in surround and that you have chosen the correct surround sound mode on the Sony for that source.