I just recently had 4 new speakers, a new receiver and a 4-5 year old shitty 12” sub and mono amplifier installed. The sub and amp are Power Bass, some brand I never heard of but got installed with a system I had in my previous car. To be honest, I didn’t know what I was buying back then but now after learning more when purchasing the parts for my new system I realized my amp is trash and want to get a new one. This may be an obvious answer for some of you, but should I get a 4 channel just for the new speakers or a 5 channel for the new speakers and the old sub? 4 channel would definitely be the more affordable route but i’m not sure what would be best. Any insight would be greatly appreciated! I can also post exactly what I have installed in my vehicle if that would be helpful! Thank you!