FAQ: Speaker/Sub/Amp Upgrades with Factory Head Unit

How much do you want to spend?

@ Randy - my converter has adjustable outputs, I fiddled with it until the sound quality was decent, along with the amp gain. I'm using a single channel amp for the sub. 6x9s are still just off the head unit.
NO, do not try to power an amp with an antenna wire. You will just blow fuses. You will have to run a seperate power and ground wire for the amp, I ran a direct power line to the battery under the rear seat. The better guage the ground the cleaner the amp will run - I used 4 guage, and the shorter the better - I used the stock under seat ground bolt so mine is kinda long at 2' or so.

Scott has it right - how much do you wanna spend? I spent $7500 on a system for my first Celica back in 1996, and I was still never happy with it when compared to others systems. If you just want some bass tacked on, 1 12" sub will do it.

wee-one wrote:

OK... so I know y'all are going to think I'm stupid... but I've got a couple questions..

If I get one 12" sub or two 10" subs... (I'm thinking just one sub tho)...

. Do I need a 4channel amp if I am going to tap into the 6x9's...?
. Will the antenna wire power the amp and the antenna....? Is the gauge big enough?
. If I bridge a 4 channel will it still power the 6x9's...?(guessing so)
. If I use an input/output converter... how much will it affect the sound quality...?
. Do I need a capacitor or Farad?.... what about mosfet???
. Is it worth replacing all the speakers or just door speakers...? From what I'm understanding the 6x9's are good enough its just the rears.... or am I getting it backwards?

Thanks guys... I know I suck at this audio stuff... I just want some bass And can get some really good deals if I know I'm not wasting the money

I'll try to help provide you with the best answers to your questions and reasons as to why if i suggest an alternative.

Q: Do I need a 4channel amp if I am going to tap into the 6x9's...?
A:don't bother tapping into 6x9's if you are planning on keeping the factory 1's. Under amplification from a quality unit these will most likely not last you the season. Best suggestion is buy a good quality component set for the front. Power that set with the front 2 channels of yoyr 4 channel amp in stereo mode. This will give you much better SQ than new 6x9'S, simply because of the locations of the speakers in correspondence to where you are situated in the car.

Q; Will the antenna wire power the amp and the antenna....? Is the gauge big enough?
A: Never, ever piggy back and amplifier off an existing power source. Always run a seperate power wire from your amp to you battery with an inline fuse close to the battery with the amps appropriate fuse size. (typically 500W= 50A) (1100W=100A) etc. When you run your ground for the amplifier never exceed a length of 4 feet for your ground cable. Always make sure the surface you mount you power and ground to are CLEAN, no painted surface beneath the grounds, and no corrosion on any of your terminals. Safest way to get your wiring right the first time if your a novice is to buy a "wiring kit". You can buy them in assorted sizes based on what wattage your system is running, 750W, 1500W, 2500W, etc. The wires will be gauged appropriately for the system.

Q:.If I bridge a 4 channel will it still power the 6x9's...?(guessing so)
A: Going back to answer #1, you will want to upgrade your fronts first, because that is where you will be riding the most. When you say "bridge" the amp I going to assume you mean just the rear 2 channels. This is called "3 Channel mode", this is the best route to go IMHO when building a basic starter system. You will want to bridge the rear 2 channels to your woofer(s), and utilize the front 2 channels for the component set. I'm not sure what head unit your running, but if its aftermarket, the internal amplifier on the head unit will be more than enough to power the rear factory 6x9's. I heavily advise going with a 4 channel amplifier with an internal 24db crossover as opposed to the 12DB. i have run many versions of both and the 24db is far superior, and more user friendly.

Q:If I use an input/output converter... how much will it affect the sound quality...?
A: Unfortunately this would be the first time I have had this question/suggestion in a system. I have never used 1 or known any1 around here who has, so I will have to reserve my answer. I am mainly more into the use of digital sound processors (epicenters). I would imagine there would be some SQ gains but whether they would be that noticeable on a budgeted system i can't say for certain. IMO i would stick to the necessities.

Q:Do I need a capacitor or Farad?.... what about mosfet???
A: Okay here's the basics, most amplifiers, if not all on the market today use a MOSFET power supply in their design, among other circuit designs and fancy names. Basically all you need to do is a little market research on what amplifier best suits what you need, both in function, and price. When it comes to 1farad, 10 farad, 20 farad capacitors, you really only base it on what size of system your going to run. We Riviera owners are gifted with a very good alternator rated at 140A to start with. So if your on a budget you can get away without a capacitor. However i don't recomend it, an alternator isn't designed to produce the kind of instantanious drains a large amp can put on it for any long period before it gives up the ghost. This is why you need to run a capacitor to store up that extra necessary power to hit and carry those long bass throws that would reek havoc on your alt. Typically they suggest a capacitor of approximately 1 farad for every 1000 Watts.(e.g. I run a 6 farad in my Riviera's system)

Q;Is it worth replacing all the speakers or just door speakers...? From what I'm understanding the 6x9's are good enough its just the rears.... or am I getting it backwards?
A: Without question do your fronts, this is where you start on your trebile speakers. Leave the 6x9's(rears) alone, and take my advice and get yourself a good component set, you won't look back.

Anyways hope I answered all your questions to your satisfaction, an other questions just holler. Audio is kinda my thing.

Good thoughts. Put your first dollars towards a 4 channel and a sub. You can run the fronts on one channel each and bridge two channels for the sub. Run the rears off of the head unit. The next phase would be to buy a good set of components for the fronts.

So I know I needed a 4 channel amp... I plan on splicing into my 6x9's for the signal and use the ant. For the acc.... and wire up one 12" sub... the amp is an Alpine mrp-f306... 4-3-2 channel.. here are the specs..

Specifications: 30 per channel into 4 ohms 50 per channel into 2 ohms 100 watts bridged into a 4 ohm mono load Frequency Response: 10 Hz to 50 kHz Signal-to-Noise Ratio: 100 dB Input Sensitivity: 200mV to 4.0V (1.0V at center detent) Speaker Impedance: 4 or 2 ohms (Stereo), 4 ohms(Bridged) Active Dividing Network Frequency and Slope: 80 Hz 18 dB per octave Power Requirement 11 – 16VDC Negative Ground

It has 2 channels bridged... a couple questions because I am useless when it come to electrical stuff..

. Will this power a sub at the.. I believe.. 4ohms for the bridged channels?
. Will I be able to power my 6x9's too... thinking I should
. Do I have to wire to the battery directly or can I just wire it all to the power antenna? I think some of y'all have from what I am gathering..
. What sub will this power(wattage/ohms wise) ... and can I go bigger if I can possibly bridge all four channels?


I got it for $20 from a coworker and just want like one 12"..... and since I want the stock head unit I have to cut into the 6x9's for the signal.... it was an alright price and I don't want to spend thousands.... what are my options with this amp? Thanks guys... nothing on Google helped except the specs. And y'all are too technical on the other thread... I just start drooling and go brain dead when I read some of that... thanks again

OK... so I bought an amp from a coworker today... I know its small but it was $20 and is 4 channel... two already bridged.. so I thought it would do OK... Alpine mrp-f306... here's the specs... please help me a little..

Specifications: 30 per channel into 4 ohms 50 per channel into 2 ohms 100 watts bridged into a 4 ohm mono load Frequency Response: 10 Hz to 50 kHz Signal-to-Noise Ratio: 100 dB Input Sensitivity: 200mV to 4.0V (1.0V at center detent) Speaker Impedance: 4 or 2 ohms (Stereo), 4 ohms(Bridged) Active Dividing Network Frequency and Slope: 80 Hz 18 dB per octave Power Requirement 11 – 16VDC Negative Ground

What can I do with this... and I thought I would HAVE to cut into a 6x9 wire for the signal I WANT TO KEEP THE STOCK HEAD UNIT... I don't want to go thru the BS of replacing it and from what I understand it is pretty good already for small applications... and I think I NEED an output/input or whatever converter if I'm not wiring to the stock stereo....? The wattages look kindof low.. but would this work with one 12"?... and my 6x9's...? Is the impendence and ohm rating OK for my application?

Thanks guys... like I said.. I suck at the stereo electronic stuff

Is this even possible.... what these people say they are running with this amp in the reviews in this: http://www.carreview.com/cat/car-audio/amplifiers/alpine/PRD_14783_1806crx.aspx?TabID=5 link?

Kindof sounds farfetched. ... 2 12's and speakers... it would be awesome if it can but it just seems a little low wattage to me? Y'all are the experts tho... what do u think.... it would be nice if Aaron could jump in since the pissing contest is over.....

PAC makes an adaptor to get the signal for the sub. I say forget about powering the rears with the amp. They are typically just used for fill with the soundstage coming from the front components.


You can get the owners manual here:

http://vault.alpine-usa.com/products/documents/OM_MRP-F306.PDF

Ok. I believe we have confused you with the antenna wire. The small guage antenna wire is only to tell your amp when your head unit is on. Think of it as the on/off button on your tv remote control. It does not give your amp any power so to speak. You will also need a heavy guage wire run from your battery to your amp with an inline fuse. This is the wire that actually powers your amp. Not nearly as complicated as it sounds. Don't feel overwhelmed. It will make more sense when you actually see it and do it.

OK... so I got it figured out with the antenna... my main thing is what subs will I be able to power.. and is it possible to get a signal from the 6x9 speakers and not power them and have them work? I guess my main concern tho is this amp... anyone know what this will power? Thanks.

Well this amp does not produce all that much power,but I think it would serve you quite well to use it for your component speakers in your doors and 6x9s in the rear. that is how it was intended to be used. This would still give you full function of your fade and balance control. Loading it up with subs could result in overheating issues. If you must have a sub, try one that has its own built in amplifier. Check out millionbuy.com. i have bought stuff from them and never had a problem. Great prices too.

One 10" tho? Maybe a 12"? Two channels are bridged... what about a cheap dual brand 12" rated at 400 Watts... I just don't understand the wattage ratings on the amp.... I guess the Guy I bought it from was using it for a subwoofer...? My main thing is can I tap into my 6x9 speaker for the signal without having to wire it to the amp and power it... if I just hook up one 12" sub to the bridged channels and nothing to the other two channels will it keep it from overheating or just waste its potential??? I just kindof want to know what I CAN do.... on one site a Guy powered 6 speakers and a sub off of it and said it sounded real good until he cranked it way up then it would clip... I can get a real good deal on two 12"s would it be worth wiring up another to this ones preamp outs? So this one for speakers And another seperate for two 12"s with the stick head...? I know I can get more wattage with an aftermarket stereo since I think it has a better amp built in... so that would essentially eliminate the need for my amp I have now... but I like the stock appearance and don't want to lose some controls and wire it..... so basiacally can I wire up a 6x9 for the signal without having to amplify the signal...? And if I do am I just wasting two channels?... I'd love it if Aaron would pipe in... thanks

Randy you can get your signal from the rear speakers without having to amp them. The big question is do you have the wire harness going to the high level input side of your amp? This is were you come in from your rear speakers and get your signal. Then run speaker wire from the output side of the amp to what ever speakers you want. What i would do if i had a low budget would be to amp your front door speakers and hook up just one of the 12" sub on the other channel. You can always add more at a later time once you know how you like your set up now. Oh i almost forgot if you dont have the high level harness i think you can get one from alpine if you give them the model number.

Quote :

. Will this power a sub at the.. I believe.. 4ohms for the bridged channels?

If your sub is 4 ohms, and is rated to take at least 100W RMS power, yes bridging 2 of the 4 channels will work. Your sub (s) will only play as loudly as 100W will enable it. With most modern subs, 100W is enough to hear the bass in your car, but not enough to be "loud" by most listeners standards.

Quote :

Will I be able to power my 6x9's too... thinking I should

Yes, you can use the other 2 unbridged channels to power your 6x9"s. Or, you may power the 6x9"s from the stock head, using your amps 2 channels to power the front door speakers (this is not a bad idea). Or, you may leave the 6x9"s out completely. This is what I do.

To use the rear speaker wires as a source, feed the wires into the high-level inputs on your 4-channel amp. If there 4 pairs of inputs, split each pair of wires and feed the extra inputs in parallel. Then you can do what you want with the amp's 4 channels (bridge the sub, power 6x9"s, or the fronts). If the amp doesn't have high-level inputs, you should use a speaker-to-RCA level converter ($20) to step down the levels before the amp.

Quote :

Do I have to wire to the battery directly or can I just wire it all to the power antenna? I think some of y'all have from what I am gathering..

You can't wire the amp's power wiring to the antenna. You must run direct to the battery, and it must have an inline fuse close to the battery's positive terminal. Only use the power antenna + lead to feed your amp's remote turn-on (Rem).

Quote :

What sub will this power(wattage/ohms wise) ... and can I go bigger if I can possibly bridge all four channels?

It all depends on the sub's RMS power rating. You can power any sub with 100W, but if the sub is rated for more power, you won't get the most sound out of it. If your sub is rated 200W RMS, you should be using an amp closer to that number if you want it to be as loud as it can be.

If your amp says it can be bridged into 4 ohms, you should use a sub rated 4 ohms. If you want to run multiple subs instead of a single, you need to be sure the final ohms load is 4 ohms (wiring two or more coils changes the impedance load). Running parallel wiring, divide by 2; running series wiring, add the loads together.

No, you cannot bridge a 4-channel amp into a single channel, but you can bridge it to 2 channels and drive a dual 4ohm coil sub using one bridged channel to power each coil. This way the sub would receive 200W total power from your amp. If you do this, you cannot power any other speakers with the amp. You are only going to get 200W out of this amp at most; remember that.

Good luck.

Yeah... I guess ill just wire one smaller sub up then... kindof depressing.. guess ill look on Craigslist for something beefier.. for the time being ill hook this one to one small sub and those two door speakers...? How hard is it to wire the doors to the amp in the trunk tho? Do I have to take the panel off? Thanks guys.

A smaller sub with 100W might not sound to bad - compared to what you have now, it will make a difference, it's just not going to rattle your fillings.

If you're going to power the door speakers, you'll want to replace them with something better. The stock 5.25" aren't made to take amp power. You might cook them. So the panels will need to come off, and you might as well lay some thicker wiring from there back to the trunk area.

With a 100w powering your woofer (assuming they are matched appropriately) you could expect it to be the equivalent of the new factory installed systems with molded built in powered woofers. Acura RSX, G5,etc. Nothing "amazing" but if all you want is a little bass to enjoy your music then it will work.

If you want something that hitsd hard, buy a second mono channel sub amp for your choice of woofer, use the 4 channel and run all of your high end speakers off it (component set & 6x9's). The Alpine may make short work of the factory 6x9's though i would look at an upgrade on them as well if you persue a second amplifier.

Yeah... that helps.. I think for the time being I will just run a small sub... do I have to match it to 4ohms tho or can I use a 2 ohm sub? What would the difference be? Ill just find one 10" or 12" in an enclosed box... and run the 6x9's for now... I actually like the rear speakers more loud anyway... I don't like the speaker to be real loud a foot from my ear... and I don't want to ness with the door panels right now either...

Someone said I can get my signal from the 6x9 wiring without powering them... how? I don't understand.. would I just splice the wire to one speaker?? And wouldn't that fry the wire taking all that juice or does it just matter what is coning out of the amp not what its sucking up from the signal wire?

Yeah... I'm def thinking just getting new door speakers and powering the 6x9's and a 10" or 12" sub... should be enough... and tweak the bass up... I def don't want to rattle my fillings out.. I had a buddy with a Tahoe that had a crazy system that would literally loosen the wax out of my ears.... I don't want that...

Quote :

do I have to match it to 4ohms tho or can I use a 2 ohm sub? What would the difference be?

The difference would be the 2 ohm sub would try to pull double the power from your amp - 200 W. Except your amp can't make that much, so instead one of 2 things will happen when you play the sub loudly: 1) the amp will get hot and decrease the output by cutting out or shutting down, 2) the amp will get hot and make smoke.

The 4 ohm sub will ask the amp for the rated 100 W and everything is cool.

Quote :

Someone said I can get my signal from the 6x9 wiring without powering them... how? I don't understand..

It's pretty easy - cut the wires to the 6x9"s and route them to your amp's high-level inputs, or through a hi-low level converter.

Quote :

would I just splice the wire to one speaker?? And wouldn't that fry the wire taking all that juice or does it just matter what is coning out of the amp not what its sucking up from the signal wire?

If you're going to splice, you should do it to both left and right sides. The amp should have two or four sets of inputs. MAKE SURE YOU KEEP +/- CORRECT. By bridging the amp, it will automatically combine L and R channels. Important: do not ever power the same wires with the amp that you are using for input. If you are using the 6x9"s wires as an input source, and you want to power the 6x9"s with the amp, the input wires cannot be connected to the 6x9"s!

Quote :

Yeah... I'm def thinking just getting new door speakers and powering the 6x9's and a 10" or 12" sub... should be enough... and tweak the bass up... I def don't want to rattle my fillings out..

I would go with an entry level 12" sub that has a power rating on the low side. Being 12" it will actually play louder than a smaller sub. Some of the higher end subs with huge power ratings won't get that loud with 100W, so avoid subs with 400W+ power rating. Go with a decent brand, don't buy the flea market crap!

Here's a link to an example of a subwoofer you should look at in your system, single 4Ohm VC 12" 150RMS/300Peak. You don't have to buy this 1, but something good quality with similar specs would be ideal.

http://www.rockfordfosgate.com/products/product_details.asp?cat_id=4&series_id=280&family_id=281&item_id=112932&locale=en_US&p_status=

That's a great choice from RF. Also JL Audio just launched a line of low cost, low-power subs, the WX:

http://www.shopatron.com/products/productdetail/12WX-4/part_number=92171/1451.0.1.1.46299.71443.0.0.0?pp=8&

Find them cheaper at Amazon: http://www.amazon.com/JL-Audio-12WX-4-inch-Subwoofer/dp/B003UDTA3W

Randy, the mono side will be for a sub channel - people can't hear stereo separation below certain frequencies anyway, so it's more efficient to run subs, even 2 or more, on a mono circuit (I'm sure you meant mono when you said analog - all your speaker outputs will be analog rather than digital).

Yes you can bridge two channels to the sub if the amp is set up for it, it usually will indicate so on the speaker outputs. You go + on one channel and - on the other. If you are wiring anything other than a sub to the amp you should use the appropriate L or R channel for that speaker to keep stereo separation.

Hey Randy, I agree with Aaron on keeping the +/- the same. There is a chart on this site to tell you what all the wires are for the rear speakers. I did this for my sub amp and it worked out pretty good. This will not hurt your speakers at all, your just steeling the signal from the wires not the power. keep asking question and we can get you through this..good luck man

Yeah... thanks guys. I think I got it figured out... its just THIS amp because its a 2/3/4 channel and channel 3&4 are already bridged. I guess the main thing is the inputs..it would be real straightforward if I had an aftermarket deck... but I don't want one that's why I am on this thread... LOL... I guess what's tripping me up is how the RCA inputs are set up with splicing into my 6x9's which y'all know I want to power as well.... the RCA inputs show a L one the top twowhich are channel1&3... and the bottom two are R which is channel 2&4.... but if the signal wires don't matter like you said... and yes I did mean.mono... thanks. Then it shouldn't matter too.much... and I figured out how to wire up the sub so that takes care of that... so I think I got it covered.... its just weird that the speaker wire adapter (which I don't have and don't plan on ordering) has 8 spots... one for each channel including a + and -... and my RCA's only have four and there's 2 channels on each... I guess that's what's tripping me up....

But with all of your help... I got.it figured.. especially with the ohm thing... thanks again Aaron. Good to know that the 2 ohm will fry it... that's what most subs I'm finding are.

Thanks again and ill let y'all know how it turns out once I get the sub...... and my car back....!!! Its been two months now for the new engine rebuild and to swap the motors.. WOOHOO!( u guys might know this but Pontiac 3800's are actually WAY different... oil filter housing.. all sorts of different size pulleys and serpentine belt.... they just put stuff in weird spots?!?)

Well.. I got my sub and amp hooked up.... oh my God it beats... one small amp and a pioneer 12"... just tapped into the 6x9 wires with quick connects and play it through a cassette adapter since I think my CD player is busted... says E20 when I insert a CD... so I use the cassette adapter and am pretty surprised... NO DISTORTION at all.... with the quick connects and my RCA converter and the cassette adaptor no static or fuzzy noise AT ALL....overall I am extremely pleased and recommend this setup to anyone... thanks for all the help guys!