MrSkippyJ

Yeah I doubt you’ll hear it unless you are in town. the fronts are MMats 6.5” and the rears are MMats 6x9. I had to cut out some of the speaker pod in the front the get these to fit and cut some of the adapter in the lids for the 6x9

I actually had to run the rear speakers wires to mine, the regular road glide doesn’t have rear speakers. But it came with the Rockford kit. the MMats soind pretty good, no real complaints. They sound A LOT better than the rockfords that came with the kit. as for the new Rockford subwoofer kit, at over $2k it’s a bit much for my taste.

Looks nice man! I had a bit of an easier time since my Road Glide's fairing has an easier place to mount an amp. I did the rockford bag lid kit but I am running all MMats speakers in my bike. I left my tour pack empty though, mostly because I really only use in on longer trips.

One amp is so much easier. why do you want to use 2?

I dont see much of a reason to run separate systems if they are both 12v.

Are they both going to be 12v systems?

How do you plan on wiring them to the amps?

You really aren't missing anything to be honest. You get less "noise floor" using the higher voltage speaker outputs for your inputs since you can run the gain lower. The trade off (typically) is that you are now amplifying a much dirtier signal. Most deck amplifiers are pretty terrible and their frequency range is usually a decent amount narrower than a preamp's range. If you compare a speaker level and a preamp level of equal voltage, in most cases the preamp will sound better. There are lots of factors and variables that can make one better than the other though. All that being said, if it sounds better to you then there really is no reason to change. Your "noise floor" will be similar across the 2 signal types with similar voltages. AKA a speaker level of 10v and a preamp level of 10v should have similar noise floors, the biggest difference will be the quality of the signal. Edit: Just saw SnowDrifter's resonse. Too add, I am speaking of using an amps high level when using speaker outputs and preamp inputs when using preamp outputs. Not running speaker level outputs into preamp inputs.

This is a tough one to answer, even though my gut tells me the Skar 12s would be better. That being said, you didn't give us a ton of info about your older (or current?) setup. You may have a box that is just really bad for those subs. I would venture to say if you are listening to low stuff you won't be happy with a box tuned to 42hz. It may not just be a matter of tuning though, you can have an incorrectly sized box and/or significantly undersized port that will kill performance. It would be super helpful if you could give out some specs on your enclosure and some pics of the subs to maybe help identify them. You probably won't get a definitive answer to which set up will be better, especially since better is so subjective. The best that can probably be done is we can help come up with a list of each setup's strengths and weaknesses to help you make a decision. Or we figure out those 15s are total shit subs and the Skar subs will just be better.

Probably some noise being picked up on the line level side. You want to avoid using speaker level inputs when possible because you get all the noise from the amplification. it’s not really an apples to apples comparison to compare preout voltage and speaker level voltage.

That’s to approximate input voltage levels. The higher your input level the lower your gain needs to be set.

In my personal opinion, unless there is a need for a line driver (really low output voltage or a LOT of amps to drive) then you really don't get any benefits from a line driver and add a place to introduce noise into your system. 4v outputs are far and beyond more than enough for your system. If it was me, I would leave it out just to eliminate unnecessary components. That being said, if you keep it in and you don't introduce any extra noise to your system then it's not hurting anything to keep it. Tune it using 0db and you'll be good to go.

Two things: 1. use 0 dB for setting line driver 2. do you really need a line driver?

whats the sub(s) again?

This is true when you are talking about component speakers. That is how you can have a 4 ohm tweeter and a 4 ohm mid and the amp sees 4 ohms. You are still sending high frequencies to to both speakers in your case. There are a bunch of terrible answers here. Your best bet is to not wire the tweeters up with that amp. Wiring tweeters on their own channel and the coax speakers on their own channel is not a solution, you will lose all stereo sound, although it probably won't hurt any equipment. Best bet is either to not use the tweeters and stick with the coax speakers (or replace them with a component set) or to buy an amp/replace your current amp with a 4 channel to run the tweeters. You can possibly run the tweets from the headunit though I'm not sure it would be worth the effort.