I was shopping around for some audio equipment and, since I'm not experienced in car audio, was asking recommendations. I plan to get a sub box with either one or two 10" subs and an amp to go with. I asked the guy about five channel amps, another place before this one recommended them, he then asked me if I have an aftermarket HU, you all know the answer. He told me a five channel amp would not sound good unless I had pre-amp outs for the front and rear speakers. It's not a clean signal. I just want to ask if you guys agree with this. Would you guys recommend just adding subs until there is a HU that we can put into the RX-8, or go ahead and get a five channel? I have after market speakers throughout. Base stereo, BTW. Would it make that much of a difference using the speaker/RCA converters?

 

You do have loss of signal when using a convertor so they are right in a way. It's not going to sound AS clean as it would should Bose have been nice and supplied RCA outs but...i definitely wouldn't do the 5 channel thing. I'd run a sub amp and then a multi channel for your other sets. I always like to isolate my sub's from my other components in regards to amplification, as this helps eliminate the need of additional crossovers to hand off the appropriate frequencies to the individual speakers. A five channel amp is not something I would recommend...

 

As far as remember, there was a thread that explained how to tap the preamp level signal in the Bose system. I know you have the base stereo, so we need to verify whether it is possible to do the same thing with the base head unit as well. Since the two head units are the same in the Bose or non-Bose setup, I don't see why would that not be possible. I'll need to check the wiring diagrams and trace the wires back to the head unit to get the preamp output wire colors or pinouts. I'll try to get to that over the weekend - but if someone can do that beforehand, that'd be great. Especially since I'm not an electrical engineer and have a hard time trying to decipher all those diagrams :p
Once you have the preamp signal, you should be OK with attaching an amp without using any converter - or at least this is how I understand it. Am I wrong?

 

If true, that will be very helpful. I thought pre-outs were generally or universally RCA. Is that not the case?

Actually let me rephrase that. Does this mean I need to connect RCA jacks to the wire or does the wire go directly into the amp? When you find what you are talking about.

 

NO NO NO....you HAVE to use Line output convertors you cannot splice RCA's directly into the harness..that is a HUGE NO NO...the pinouts are the same on the BASE stereo you just have to go from the HU instead of the AMP in the back deck....the colors are the same.

 

I've posted the HU connections in a thread: https://www.rx8club.com/showthread.p...threadid=21153

Didn't use a line level converter though. The Soundstream Edge amps have a floating ground compatible input with adjustable gain. Seems to be working fine (there was an ignition-on popping issue, but I don't think this is related to the line-in connections.)

 

Nufan-
Follow the custom sub box install in the link in my sig block below... I built a custom dual 10" box designed to fit deep into the trunk without taking up too much space. On the last page or so of that thread I've got pics detailing which pre-amp wires coming from the head-unit you can tap into. These should be the same connections for both Bose and standard configurations, since the head units are the same.

I agree about separate amps for the subs vs the rest of the speakers- much easier than dealing with separate crossovers. I for one did not use line converters- I just spliced my RCA's into the pre-amp output wires, and my system sounds fantastic.

 

I had already planned on it. I liked the small box you made.

 

Quick question. Since I have the stock stereo (no bose amp), I can just splice the RCA's from the amp (for subwoofer) into the rear speaker wires. Right? (being sure to get the + and - correct)
I don't have to tap into the wires behind the headunit, should be the same wire since there's no amp in-between. Sorry, this will be my first time installing an amp but I've got some practice w/ soldering and replacing speakers.

 

Yes- that's what I did at first... I would recommend using line converters though unless your amp has the capability to handle both line-level and speaker level inputs (my Alpine has both, so I didn't use converters).

I also recommend using the blue wire tap connectors I show in my pics- they make it very easy to tap into the rear speakers, and they remove cleanly if you have to.

 

Yes, the amp has a switch for low or high input voltage. thanks,