Sound quality of running 3.5mm into RCA and then outputting to subs?
My setup is near complete, aside from the fact that I need to integrate my carputer (a gateway laptop) into my sound system. Right now, I am running a Pioneer DEH-P6400 head unit into a 500/1 JL Audio amp with 2 12s. I intend to load up my carputer with mp3s and use it as both a system for my front end (most likely going to be streetdeck) as well as a storage device for my music. So heres the situation: The laptop has a single 3.5mm output jack. The HU has a wiring harness (which I've already wired into the car), a low density output (RCAs running to my subs), a front output (not sure if I need this at all) and most importantly, an IP-Bus input (don't have the adapter yet but it's in the mail on the way here).
My original intention was to simply run a Y adapter 1 phono plug to dual phono (RCA) into the IP-Bus connector. Then I realized that sound quality would probably be horrible so I started looking for an external sound card for the laptop through which I could connect to the IP-Bus. Searching around on forums, I came across this post which has probably been by far the most helpful: http://www.mp3car.com/vbulletin/the-faq-emporium/32430-how-to-get-sound-from-pc-to-car-stereo-amp.html It covers nearly all the bases and answered a lot of my questions BUT I couldn't find any info regarding how the subs would be affected if I was running a source from 3.5mm (laptop) to RCA input (HU) and then outputting the low density (into the amp). The second diagram on the post is as close to my situation as it gets, aside from the fact that I will only have one 3.5mm jack if I don't get a sound card. Also, it seems a lot of people have a lot of bad things to say about converting from a single 3.5mm jack into RCA outputs so I'm a bit concerned about that.
If anyone can explain my situation to me a bit better than I understand right now, I would greatly appreciate it as I'm confused out of my mind on what I should do. I've done plenty of searching on the car audio section and can't seem to find a consensus. It just seems that everyone has a different opinion on what is good and what is not. If I could just get an explanation as to how one set up is better than another, that would help a great deal. I'm guessing the obvious answer to that question is getting a new external sound card as I've read many people have done but yet some people feel it is completely unnecessary. Thanks! (btw, I searched 'laptop' under the car audio forum and came up with nothing :-/ not sure what kind of key words to search for in my situation so I just read anything that was somewhat relevant)