What is the purpose of having 4 inputs (Front L & R ; Rear L & R) in a 4 channel audio car amplifier? Does it mean that each channel is amplified
![Amazon.com: Pyle 4 Channel Car Stereo Amplifier - 4000W High Power 4-Channel Bridgeable Audio Sound Auto Small Speaker Amp Box w/ MOSFET, Crossover, Bass Boost Control, Silver Plated RCA Input Output -PLA4478 : Amazon.com: Pyle 4 Channel Car Stereo Amplifier - 4000W High Power 4-Channel Bridgeable Audio Sound Auto Small Speaker Amp Box w/ MOSFET, Crossover, Bass Boost Control, Silver Plated RCA Input Output -PLA4478 :](https://images-na.ssl-images-amazon.com/images/W/MEDIAX_792452-T2/images/G/01/aplus/detail-page/PLA4478_diagram.jpg)
Amazon.com: Pyle 4 Channel Car Stereo Amplifier - 4000W High Power 4-Channel Bridgeable Audio Sound Auto Small Speaker Amp Box w/ MOSFET, Crossover, Bass Boost Control, Silver Plated RCA Input Output -PLA4478 :
![Installed 4 channel amp, only had 1 pair of preouts left after recent sub install. Plenty of bass from subs but no longer hearing any of my other speakers. Do I need Installed 4 channel amp, only had 1 pair of preouts left after recent sub install. Plenty of bass from subs but no longer hearing any of my other speakers. Do I need](https://i.redd.it/0xyvs9yrz1u61.png)
Installed 4 channel amp, only had 1 pair of preouts left after recent sub install. Plenty of bass from subs but no longer hearing any of my other speakers. Do I need
![Amazon.com: KICKER Amplifier and Amp Kit Package of 2 Items - CX Series 360W RMS Class AB 4-Channel Amplifier and Complete 8AWG Wiring Kit : Electronics Amazon.com: KICKER Amplifier and Amp Kit Package of 2 Items - CX Series 360W RMS Class AB 4-Channel Amplifier and Complete 8AWG Wiring Kit : Electronics](https://m.media-amazon.com/images/W/MEDIAX_792452-T2/images/I/61qtMpnR5rL._AC_UF1000,1000_QL80_.jpg)