Adding a 4 channel is a pretty lengthy install. But if you know what you're doing, it's not too bad. You would need a set of 4 channel rca's, or 2 sets of 2 channel, plug them in to the front and rear pre-outs, and run them to the amp. The amp then has speaker wire outputs which are designed to be connected to the speakers. You could run them all individually to the speakers, but that would be a pain in the butt. Another option is to run speaker wire back to the hu and attach them to the speaker leads going to each speaker (cutting the wire from the hu and taping them individually so they don't ground out). If you do that, make sure you run the speaker wire on the opposite side of the car as the power wire since they will definately pick up engine noise if you don't.

A third way (and easiest in my opinion) involves a little more knowledge, and is a little trick we do at my shop to make things easy. Basically, you cut the speaker leads behind the radio, tape the side connected to the radio so they don't ground out, and connect the front and rear leads together. Connect the left front positive to the left rear positive, then the left front neg to the left rear neg. Repeat for the right side. Then run speaker wire from the rear channels of the amp directly to the rear speakers (since yours is a 4-door, run it to the pillar seperating the front and rear doors and connect them to the speaker wire running into the door. Completely cut those wires making sure they are the correct ones and attach the amp leads to the side running into the doors. The wires are most likely twisted together.). Then, run speaker wire from the front channels of the amp to the opposite side of those same wires in the pillar. This will send the front channel amp signal along the rear channel leads up towards the head unit where it will connect to the leads going to the front speakers and thus amplify them. I don't know if you have 4x6's in the dash, but if you do, you may not want to amp them since they're already fairly loud without an amp. It you do have them and decide not to amp them, run speaker wire from the front outputs on the hu directly to those speakers.

I wouldn't recommend going any higher than 500 watts rms on 8ga, and even that can sometimes push it. If you start popping fuses, or you notice the amp goes into protection or starts clipping and you're not over-doing it, you might want to upgrade to 4ga. Pulling out the 8ga would be fairly easy. Running new 4 gauge might involve taking the seat belt bolt on the floor out on whichever side you're running the wire down. That's the only main hard part. Some people have a hard time finding a way through the firewall as well. There's 2 places to go through on 98 - 02 Blazers. The grommet on the passenger side near the floor against the firewall where the antenna comes in, and a trickier grommet on the driver side where the main harness enters the engine bay. It's a larger grommet, but the harness goes through at an angle. So be extremely careful not to damage any wiring here if you decide to go that route (it's a pain to repair wire here). The passenger side is much easier since the battery is mounted on that side anyways.

Let me know if you have any other questions. I've done pretty much everything there is to do in terms of audio electronics as well as remote starts and alarms on Blazers. Aside from custom work.

 

ok, well my headunit says 50wattsx4 so i dont really needa 4way amp but there seems to be almost zero bass coming from my speakers if i turn my subs off.do you thinkif i wire to somehow attach a 4 ga or 2ga cable to the end of my 8ga, i could just kinda pull the ga out bringing the4ga along with it. i have a 460x1 amphooked up to cheap 12" subs butmy b-day is coming up and i've been thinking about getting a 15" kicker compVR with a 750x1 amp which means i'm probably gonna have to rewire it

 

I know it says 50 x4, but that's peak and you'll most likely never see that much. Where I work, we go by RMS or continuous power. Which would be somewhere between 18 and 22 watts for that particular hu. I would not recommend adding a larger gauge wire to that. It would be much safer to just rewire it to all 4ga. Especially if you're gunna connect it to an amp that powerful. Are you looking at the Kicker zx750.1? Ifso, I've installed them a few times. They're extremely underated. They actually push somewhere between 900 - 1000 watts rms. Honestly, I think most 15' subs are impractical, aside from competitions. Two 12' compVR's would be fine with that amp as well. You might want to think about getting the compVX's instead. They're a little more expensive, but they're worth it. I recently had a guy come in with 2 of those and the Kicker zx1000.1 and it was extremely loud.

 

wellim looking for something smaller, the box i have takes up a lot of space, wheel to wheel and from the back of the seat to about halfway through the cargo area. plus ive found a place with the 15"compVR for a good deal. that zx750 was the amp ive been looking at.would a 4ga be capable of 900-1000 watts? or should i switch to 2ga while im at it? the sub says 1500peak so i think that would be a pretty good setup. also what would be the best 4x6 speaker for the dash? i found some kicker ds series for $40 which seems good to me.

sorry about all of the questions but i wanna get help while i can from someone who knows what they are talking about and isnt giving me bs and trying to get me to buy stuff from them. thanks for all of your help


EDIT: actually i was just looking at the crutchfield website, the 15 compVR is at 4ohm and the zx750.1 amp is 750watts at 2 ohms and 375watts at 4ohms so i might reconsider on what to get

 

That's cool. Hey, the main thing that matters when building a system is listening to stuff and finding what sounds good to you. No one elses opinion on what sounds good should matter since you'll be the one listening to it.

4ga should be fine on that amp. If you're pushing the sub kinda hard and you notice the amp going into protection or anything else I said before, upgrading to 2ga might help you out. Also, make sure the ground wire is secure and is as short as it can possibly be. I try to keep mine to a foot or less. The shorter the ground wire, the more efficient the amp is and the cooler it runs. This can help prevent it from clipping or going into protection.

For 4x6's, I'd recommend Polk, Kicker, or Alpine if you have the cash. DS series Kickers are their lowest series if I'm not mistaken. If you have a chance to listen to them, go for it and see what you like. Go to a local store that sells them and take a listen with and without an amp if possible. $40 isn't bad for those speakers by the way. If you want to know what I did, I ended up getting Polk db6501 components for my doors and I ran the tweeter to the dash speaker location. I've installed enough 4x6's there to know that I personally don't like them. They're overall louder than the other speakers since they're right in your face, and I didn't want that. You may like them tho. You'll never know until you try.

No problem. Feel free to ask me anything you want.

 

Those subs are dual 4 ohm. Basically they have 2 voice coils, kinda like having 2 subs in one. If you wire the coils in parallel, they present a 2ohm load to the amp.

 

how would i go about wiring them in parrallel? they sell a 2 ohm 15"cvr but i dont know if i can get that one on sale. i found it locally for $110 and im really hoping the guy doesnt sell it. do you think if i taped the end of a 4ga cable to my 8ga cable, i could just slide it through to the back?

 

If you get a dual 4 ohm sub, it will have 2 sets of positive/negative terminals. To wire in parallel, you connect the positive terminal from one voice coil to the positive of the other voice coil, then connect negative to negative. Then take speaker wire and connect it to the positive and negative terminals of either coil (must use the same coil, can't use positive from one and negative from the other) and connect that to the terminal cup on the inside of the box.

 

oh ok. that seems simple enough. thanks again

 

Forgot to answer your other question...

Yes, you should be able to just tape the 4ga to the 8ga and pull it under the carpet to the back provided the 8ga wasn't run through anything with a tight squeeze and the tape holds on long enough to do so. If you use enough tape it should hold on fine.