2nd Gen Non-Engine/Transmission Weird Infinity speaker problem

[fulltimer]

After installing aftermarket radio I noticed that I had to crank the volume way up to get sound.



Checked the speakers and I get no sound from front two large speakers, normal from front two tweeters, very low from right rear, and normal from left rear.



I am pretty sure that I wired it right. I used one of those wiring adapters

and I put power to the amp wire.



Any suggestions?

 

[LVJUNIOR]

Mine is a 98 and may be different but the stock speakers have an amplifier built in and I had to wire the amplifier circuit up to the aftermarket radio.