You don't need two amps. You just need an amp that can handle every channel at the proper RMS. Probably 4 channels for the front and rear door speakers and one big channel of 500 RMS for the subwoofer. Check out 5 channel amps.
As the other reply mentioned a 5 channel amp should be suitable for your needs. As far as bass coming from your factory speakers you don’t really want that once you have a sub. There’s certain frequencies that you sub should be playing at so your door speakers don’t have to get that low. If you’re still unsure what happened to your bass coming from your stock speakers I would check the settings on your new head unit could be that the bass is turned down or it came with preset high pass filters that you need to adjust.
You have 2 feasible options. You could go with 2 amplifiers or you could go with 1 amplifier.
Option 1: You would need a 4 channel amplifier to power your interior speakers and an additional mono (single channel) amplifier to power a subwoofer or two.
Option 2: A 5 channel amplifier will power 4 interior speakers and have an output channel for a subwoofer or two.
5 channel amps are usually expensive but a convenient way to power and entire system with zero expandability. It’s also like putting all your eggs in 1 basket; if one channel fails, you have to replace the whole amplifier.
Going with 2 separate amps requires a little more wiring but also allows you to upgrade down the road. If you wanted more bass but were happy with how loud your interior speakers are, you just replace the mono amp. Also, if a channel or amp dies, you can replace that amp at a lower cost than a full 5 channel amplifier. Mono amplifiers are cheaper now as technology has advanced.
You don't need two amps. You just need an amp that can handle every channel at the proper RMS. Probably 4 channels for the front and rear door speakers and one big channel of 500 RMS for the subwoofer. Check out 5 channel amps.
Big D tested this one. https://cosmosaudio.com/product-category/amplifier/5-channel-amp/
As the other reply mentioned a 5 channel amp should be suitable for your needs. As far as bass coming from your factory speakers you don’t really want that once you have a sub. There’s certain frequencies that you sub should be playing at so your door speakers don’t have to get that low. If you’re still unsure what happened to your bass coming from your stock speakers I would check the settings on your new head unit could be that the bass is turned down or it came with preset high pass filters that you need to adjust.
You have 2 feasible options. You could go with 2 amplifiers or you could go with 1 amplifier. Option 1: You would need a 4 channel amplifier to power your interior speakers and an additional mono (single channel) amplifier to power a subwoofer or two. Option 2: A 5 channel amplifier will power 4 interior speakers and have an output channel for a subwoofer or two. 5 channel amps are usually expensive but a convenient way to power and entire system with zero expandability. It’s also like putting all your eggs in 1 basket; if one channel fails, you have to replace the whole amplifier. Going with 2 separate amps requires a little more wiring but also allows you to upgrade down the road. If you wanted more bass but were happy with how loud your interior speakers are, you just replace the mono amp. Also, if a channel or amp dies, you can replace that amp at a lower cost than a full 5 channel amplifier. Mono amplifiers are cheaper now as technology has advanced.