wiring suggestion

I am new to car audio but I want to install a small system in my 2002 trailblazer.  I have new Memphis speakers for the doors an alpine head unit an alpine sub and an alpine 4 channel amp and a kicker two channel amp.  What should I hook up to what.  Also should I run speaker wire from the speaker to amp or splice the wire on the head unit? I have heard different things. If I run the speaker wire to the head unit do I still have to use rca's? Finally do most rca's have built in remote turn on or do I have to run that wire also? Thanks!!!!

P.S The 6.5 memphis speakers came with a crossover ( I think ) Do I need to use it?

RCA's come either way, with or without remote turn on.  I would suggest without because the remote and power wires tend to add in unwanted noise to signal wires like RCA's.  RCA's need to be kept as far away from power and remote wires as possible.

Definitely use RCA's from head unit to amp as opposed to speaker wires.  THis will give the amp a cleaner signal.  Music will sound better.

IN order to tell you what to connect up to what, we will need to know more about the amps and speakers.  Particularly the wattage outputs per channel of each amp.  And it is less important to know the PEAK wattage as it is to know the RMS wattages.  Peak means very little. 

But just guessing, I'd say that since you only mentioned one sub, then you will be using the Kicker amp bridged to that, and the Alpine amp to the main speakers.  And if the speakers came with a crossover, then you should most definitely use it.

etusick wrote:

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P.S The 6.5 memphis speakers came with a crossover ( I think ) Do I need to use it?

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Uh, yes.  What model are the speakers?

OK, I'm back.  First let me say WOW what a nice amp that Alpine is!  I'd like to have that myself. 

Here's what I found out.  You have a set of Memphis coaxial 2-way 6.5" speakers with swivel tweeters and these speakers have separate crossovers for the tweeters.  You need to use these crossovers to feed the tweeters only the correct frequencies.  Without them it will damage the tweeters.  By the way, swivel tweeter means that you can angle it so it points more towards your listening position for the best sound possible.  I could not find any information on the wattage handling of these speakers, but the Alpine amp puts out a nice amount of wattage that should not be too much for these speakers to handle.

The Alpine amp is a 4-channel amp that puts out 55 watts per channel RMS on a 4 ohm load, which is what most speakers are rated at(yours should be as well).  This is really good.  Don't know what the PEAK wattage is, but it's unimportant really.  I would recommend running the Memphis speaker on the front channels of this amp.  This amp also has a subsonic filter on the rear channels @ 15 Hz.  The amp's specs said this was for filtering noise at the sub-human-hearing level so that it doesn't eat up power output in the form of useless energy.  You wouldn't hear it but it makes it more efficient so to speak.  That's just a nice quality in the amp, but doesn't affect how you use it.  I don't know if you are using any rear speakers or not cause your post didn't mention them.  But you could run another set on this amp, or you could bridge the rear channels and run your sub on them.  The amp has a built in crossover that is variable from 30 - 400 Hz.  If you use it on the sub, then use the crossover set at LP or Low Pass so only bass goes to the sub, and no treble.  Set the crossover frequency to what sounds best to you, but I like about 60 - 80 myself.  Depends on the sub.

Speaking of sub, you didn't mention anything about it other than it's an Alpine.  Is it a 10 or 12 or what?  How many ohms?  That affects the way you hook it up, so we need to know that BEFORE you connect it to any amp.

The other amp you have is a Kicker 200.2 and it is rated at 100 watts per channel at 2 ohm, so it should be 50 per channel at 4 ohm.  You can bridge it into a 4 ohm load and get 200 watts into one subwoofer.  Kicker's website did not say if this is RMS or PEAK wattage, but I would hope that this is RMS.  If not, then this is a small little amp and not worth a whole lot to run a sub.  It can do pretty good, but there's definitely a lot better out there.  I liked the Alpine a WHOLE lot better.  Also, the Kicker amp has a variable crossover from 50 - 200 Hz.  Selectable from LP/HP/Full, which is just whether it is low bass only, or only highs like midrange and treble, or full range which is everything.  You just select the frequency you want it to cut off at.  Same with the Alpine amp's crossover.

All in all, you have the makings of a modestly nice system.  You could just use the Alpine amp to power the front speakers, and your subwoofer, and run the rear speakers(if you have any) on the Alpine deck's speaker outputs.  Or use all 4 speakers on the Alpine amp, and use the Kicker amp to run the sub.  If you use two amps with all channels used, then you will need at least 3 pairs of RCA outputs on your deck.  If the deck doesn't have that many, then you can use a RCA splitter to turn one RCA into two.  You'd need two of these so as to make a pair of RCA outs into two pairs.  I wouldn't recommend splitting the signal more than one time though(so I hope your deck has at least two pairs of these RCA outputs).  If it doesn't you may want to think about just using only the Alpine amp and forgetting the Kicker.  Or getting a line driver to help with the voltage output on the RCA's coming from the deck.  You could split one pair up into three pairs(I don't recommend), but splitting it up too many times degrades the signal the deck sends to the amps.  That's why I don't like to do it.  What model of deck do you have??  That may make a difference here.  I'd like to check that out too.

Yes, you can use whatever type of wire for remote turn on.  It's just a signal wire.  I would use an 18 gauge stranded though.  Solid wire like house wiring is hard to work with in a car and some say it affects how well the current flows through it, but I don't think so on that.  I myself just used one side of a speaker wire(not connected to a speaker of course) that I peeled off of the other side and ran it to my amp.  It worked fine and that's all I had handy at the time, but I would have preferred buying one instead. You can usually get this wire sold by the foot for about $0.08 per foot so you would only have about $2.00 in it if you just go to Lowes or a hardware store.   Also you don't want to use the one on the harness.  That would only be for if you had a power antenna that needs activated or a factory amp built into the car.  You need to just run one from the deck's remote lead to your amps.  You can just splice it to go to both amps since you only have two.  That's not bad.  If both amps are pretty close together then it will be easy to splice without running two runs of long wire all the way from the deck. 

3 sets of RCA outs is excellent.  You can use both amps without using splitters if you want. 

Yeah, you will have to run speaker wires from the amp to the crossover and then from there to the speaker.  Should be one crossover per speaker.  Is that what you have??  Information I found on these speakers was limited or I would give more details on how to do this.   I didn't even get to see a picture of the crossover. 

And yes 16 gauge wire is a good choice for what you are doing.  Very good.  You will be pleased with this.  For the record, so you don't get confused, wire gauges are in reverse of what the numbers might suggest.  16 gauge is larger than 18 gauge(just like shotguns, a 12 gauge is larger than a 20 gauge.  If it wasn't, then a 410 would be huge!!).  I wanted to say that so you would understand why you use 16 on speakers with lots of power, and 18 which might have seemed bigger on only a remote wire.

Finally, what ohm load are your sub's voice coils??  If you wire them in series, you have twice what one is by itself.  If they are in parallel, then it's only 1/2 of what one is by itself.  I put up a post on this site entitled:  "Look!  Parallel ohm formula for subs in parallel" or something like that.  Search for it and it will explain more about this so you know what's going on.  It was about a week ago so it might be on page 3 or 4 by now.

I'll get back to you on the rear speakers if there is anything special you have to do with them after I check them out.  Did they come with crossovers or anything?? 

Also, did you get an antenna wire adapter with your wiring harness you bought.  The antenna wire lead will be smaller than your receiver needs.  After about 1988, GM changed over to that smaller size, and sometimes the wiring harness comes with the adapter and sometimes not.  Depends on where you bought it at.

One other suggestion.  Since you are new to car audio you should go to www.crutchfield.com and request one of their free catalogs.  It has tons of gear in it and usually lots of information about what all the specs like frequency response and signal-to-noise ratio is and all that.  Then once you get the catalog, you can go through it and find where they offer a free guide to car audio installation.  Call and order it, it's free, and it will teach you a ton more than the catalog did.  I learned a HUGE amount when I first got started by doing this. 

It's been several years back that I did this, so I'm not sure they still offer it, but if they do, it's well worth it since it's free.  It will by no means teach you everything you would need to know, but it's a great starting place so you have references and can get a good idea of what's going on.  However, the prices on the gear in their catalog are what I would call "high retail".  This is as much as I would ever expect to pay for any new gear.  You can get stuff a lot cheaper on the internet, so I say don't buy from them unless you just want all the extras that they give you like instruction sheets for your particular vehicle, and free harnesses and kits and all that.

Once again, limited information.  All I found out was that you have a 5.25" round coaxial speaker.  It did not mention if it had a separate crossover, but I do not believe it does.  No wattage listing either.  But it should be fine on the Alpine amp's output wattage.  Just don't drive it into distortion.  All the website had was the "new for 2005 version" and it said it was reworked for 2005 so you may not have the exact same thing I was looking at. 

Is 5 1/4" the actual size that the 2002 Trailblazer takes in the rear(no puns intended......seriously)??  So you have 6.5's in the front and 5.25's in the back.

No I don't know about tapping that ignition wire.  Why do you need to relocate the factory stereo??  Is it something to do with not losing other things like door chimes or alarm or something??  Also, are the speaker adapters to mate with factory wiring?? 

Also, there is now a new and very important issue with the sub and amp that we have to look at.  If you have a 4 ohm DVC, then it's going to be difficult to work with and get enough out of it.  In a nut shell, if the coils are wired parallel, then it will be a 2 ohm load total.  You cannot bridge this to an amp only stable at 4 ohms bridged.  That's exactly what your amps are, 4 ohm stable bridged, 2 ohm stable stereo. 

So, you need another sub just like the one you have, or another amp, a mono amp that can handle 2 ohms. 

Otherwise, you can wire series, for 8 ohms, but that will cut bridged power in half and would only be 100 watts.  This is where it comes in whether that Kicker amp is rated RMS or PEAK(remember me saying that before?0.  If it's RMS, then that's ok, but still kinda weak considering that the other speakers will get 55 watts RMS each.  IF it's PEAK, then that just plain sucks.  I don't know which it is.

Still, you can wire one coil per channel and that will be a 4 ohm load stereo, and that will still only be 100 watts total cause we said it would be 50 x 2 @ 4 ohms before.  That would be the same as bridging it 8 ohm wired though.  No way of doing it to get the 200 x 1 @ 4 ohms.  And before you ask, I don't recommend using only one coil unless you know that it is rated to handle the 200 watts by itself and know for sure which the amp is pushing RMS or PEAK.

Well, this is a snag, but don't be discouraged.  You can still come out of this ok.  Even if you ran it stereo at 4 ohms, it will still be bassy, but maybe not as bassy as you would want.  Good thing it's a SUV and the sub will be inside with you instead of a trunk.  That will help some if you decide to only use this one sub. 

Thanks again! Relocating the factory stereo would be for the chimes, but I do not care about losing those so he told me to tap a brown wire under the steering wheel with the red ignition wire on the head unit. He said that this would work, and I would not have to relocate.  I am starting to get confused about the sub. I have the manual for the amp and it states: RMS POWER in watts all channels driven     4 ohm stereo 70 x 2 , 2 ohm stereo 100 x 2, 4 ohm mono 200.  Also states Low impedance operation stable in 2 ohm stereo or 4 ohm mono loads.  If this is a snag could I wire the sub to the alpine amp and use the kicker for the back door speakers or would it be cheaper to get a 2 ohm sub and get rid of the one I have?

Alright, now we have some actual owner's manual amp specs to work with here. 

OK, wait a minute.   No matter which amp you run the sub on, you will still have the same problem.  Both amps are only stable at 4 ohms bridged.  This means that they can handle a minimum load of 4 ohms when they are bridged.  Bridged is when you wire two of the amp's channels together to create one channel.  So when you bridge your amp, you have to make sure that the subwoofer is no less than 4 ohms.  They can take more ohms, like 8, but not less than 4.  Get it??

Your sub cannot be wired for 4 ohms only.  It is either 8 ohms(with coils in series) or 2 ohms(with coils in parallel).  The only way your sub can be 4 ohms is if you don't wire it at all, but rather leave both coils separate and independant of each other.  Each coil is 4 ohms that way, but you would have to run it with one coil on each channel of the amp.  See now??  And I think I said once before, not sure, that I do not recommend just using one coil so it would be 4 ohms.  Wattage handling of the subwoofer may not be sufficient to allow that.  I don't know your subwoofer specifically, but I don't think this is a good idea anyway.

So if you did run one coil per channel, then you will get 70 watts RMS per channel, which will be 140 watts RMS going into your sub.  This is not bad.  Yeah, the amp could do a little better if you had an actual 4 ohm subwoofer that was not a DVC.  Then it would put out 200 watts RMS, but with your sub, you just can't do that.  You could get another subwoofer just like the one you have and run two of them in parallel and get a 4 ohm load that way.  You'd get 100 watts per sub.  That would be a little better, but you'd have to decide if it was within your budget. 

It's just a situation where your sub and your amp are not ideally suited for each other.  If you wire it up the way I said in stereo though it will be OK.  Or you can also wire it in series(8 ohms, remember??) and bridge the amp and get 1/2 of the 200 watts, which would only be 100 watts.  That way it's less and I don't recommend this.  But those are your two options with that amp and that subwoofer.

When you say get rid of your sub and get a 2 ohm sub, I think you are confused.  You might get rid of it and get a 4 ohm sub and do better, but a 2 ohm sub would make it worse.  You'd need two of those to do any better.

See, what it is is that the amp can only take certain ohm loads as a minimum depending on the way it's used, either bridged, or two channel stereo.  Your amp's manual is showing you that.  It also tells you the power outputs you will get with the possible ways of wiring it to different ohm loads.  That's what all those numbers are. 

You have to make the speaker and amp match.  With your sub and amp, it's hard to do cause of the DVC 4 ohm part.  Understand??  I hope I'm making this clear enough. 

As for the brown wire tapping and all, you're on your own there.  I don't know how to do what it is that they are saying.  I've never dealt with that issue before.  Sorry.

Your idea of getting a DVC 2 ohm sub instead of the DVC 4 ohm is correct when you are using a two channel amp.  You'll then be able to achieve a total 4 ohm load.  It would have been helpful for the dealer in question to get you the proper sub to begin with.

But a couple of points to clarify here:  " Bridged is when you wire two of the amp's channels together to create one channel."   You can't create a channel.  You are connecting two channels into one load, so the load (the subwoofer) gets half its power from one channel and half from the other channel.  The load impedance goes half to one channel and half to the other.

On wiring coils independently:  Yes, only one coil can be used and the other left unused without harm done (as long as the power handling capability of one coil is not exceeded).  There is rarely a reason to do this, and there is no reason to consider this in your case.  A change in equipment is called for.

...have the manual for the amp and it states: RMS POWER in watts all channels driven     4 ohm stereo 70 x 2 , 2 ohm stereo 100 x 2, 4 ohm mono 200.

The spec here indicates that this is an amp suitable for a pair of components but not for subwoofer use.  Notice how the wattage is not doubled when it goes from 4 ohm to 2 ohm?  It's just a little higher.  That means the amplifier is not built to handle the full current at a low 2 ohm impedance (4 ohm bridged).  But it should work fine as a coaxial or component amp at the rated 4 ohm impedance.

You should do an exchange at the dealer unless you have some closeouts or something and got a great deal on them.  But if you want to use that sub, you should have a D class mono amp capable of powering it to at least half its RMS capability.  A mono amp is one channel and therefore rated to deliver at 2 ohms.

or is it better to get 4 ohm DVC?

You already have one of those.  And as far as that amp goes, use it for a pair of component speakers and it will work out fine.  But not for the sub.  You would have to replace the sub to use that amp.  One or the other.