Stock head unit with aftermarket sub

[marshalllaw18]

I just got some subs and I want to put them in my P5. I don't have the spare tire sub so I was figuring that I could just connect the outputs from the head unit that normally go to the spare tire sub and connect it to an amp and my subs. I think this should work, please correct me if I'm wrong because I don't know very much at all about car audio. Thanks.

 

[1sty]

Seems right if I am fallowing you.

You can use an amp with the facotry head unit so long as that amp has a high level (also called speaker level) inputs.

What amp are you using for th esub?

 

[marshalllaw18]

I don't have an amp for my subs yet. I just got 2 MTX Thundercast 1000W subs, but no amp. I was planning on looking at some amps today. I just want a cheap amp, because I am poor. I definitely don't need something that can put out 1000W, I just want something to drive the subs. The cheaper the better. Any suggestions.

 

[1sty]

An underpowered amp is the second most common cause of a blown sub. People try to make it push omehting it basicly can't it goes into distortion and smokes the sub.
If you can't afford a proper amp for 2 subs right now then get an amp that can handle one of them and only use one for th etime being.

What is the actual modle number of the subs you bought?
THat 1000 watts is total BS. Its not BS from you, but rather a marketing gimmic car audio companies use to impress some people by slapping a large number on a box. IF you can give me the model number I can figure out exactly how much power the subs need and at what impedance.

 

[marshalllaw18]

I'm not sure what the model number is, this was printed on the outside of the magnets, not sure if it's what you need:

12XF1101 4 OHM
557 9510

As for the underpower issue. If I get a 300 W amp, and run it at 200 W to the sub, how is that different than running a 1000W amp at only 200 W power. I would think that it wouldn't matter as long as you don't overdrive the sub.

Also, I was planning on using just one of the two subs becuase I don't want a huge sub enclosure sitting in my car and I don't really need the extra power. And it will be easier to find a cheaper amp.

 

[Dexter]

because if the sub wants 300w, it wont be there and j00 r fux9rs

 

[1sty]

Are you sure you typed in that number on the basket correctly?
It doesn not list as ever being an MTX sub nor does a google search bring anything up.

AS for the power issue. Underpowering a sub is dangerous as most people try to make the amp push the sub to a level it simply can't go with a small amp powering it. Hence they crank up the gain and force the amp to clip. Clipping is distortion and that is what will kill a sub. So long as the amp is never driven to clip by setting the gain to high then the sub will not be damaged so long as you don't turn the radio or bass boost or anything else on in the radio which will also clip and again damage the sub.

 

[servoeyes]

What 1st is saying is that when you under power a sub, you are not moving the motor with enough force to create the sounds you want. Often, this will lead to user error, where the gain on the amp is cranked and the volume is turned up such that you introduce distortion. It's a lot harder to overpower a speaker (especially a sub) because that's a rating taken at a continuous rate for a certain amount of time. Usually a sub hits and then the wattage drops to whatever it needs to play the other notes. However, it's distortion and too much clipping that truely fry any speaker...well...that and over extension (which is just throwing waaaaaaaaaay too much power at it...this is also known as speaker porn)

 

[marshalllaw18]

I am sure that I typed the number in correctly, but I don't think it's a serial or model number. I couldn't find anything about the number on google either. I e-mailed MTX and asked them if they could tell me what sub I had. Still waiting to hear back from them. As of now my plan is to make an enclosure for 1 of the sub's. Then buy a small amp. Then connect the unused output of my stock head unit to the amp and the amp to the sub. I'll have to be carefull not to overdrive the amp so that I don't blow my speakers. Does that sound right?

Also, assuming I want to build a 2 cu ft enclosure for my one 12" sub, would I want a 4 cu ft enclosure if I wanted to put both sub's in there?

 

[servoeyes]

better to split it down the middle...welljust make sure that both subs have their own chamber in case one sub shorts and the other keeps going. Then you overpower it by having it in a box 2x what it needs...

 

[1sty]

where did you get these subs?
2 cubes is a starting point, you can make adjustments larger or smaller depending on the manufacturers recomendations.

THere is not an unused output form the deck. The wires going to the stock sub are just tapping the door speaker wires and splicing the singal. You need to be surre your amp has speaker level inputs to take advantage of it. YOu will also need a new power and ground wire of adaqute size.

 

[marshalllaw18]

I got the subs from a friend who bought them from his boss, and I have no idea where he got them from. Thanks for all the help and info, I think I have a pretty good idea what I have to do now. Now I just have to do it.

 

[NothingFlashy]

Stock head unit with aftermarket sub in 2002 p5

I wanted to carry this thread on a little further. Hope someone can help out...

I was looking to install a couple of simple, smallish subs in my 2002 p5. So, I had a cousin who got me a deal on a two 8 in. subs and an enclosure to house them both (that also has tweeters built in). He also had a spare amp kicking around. So, all set.

Turns out he also knew a guy to install them. The guy mentions (after installing it) that the stock head unit did not have some "RCA" port, or what not, to connect the amp directly to the head unit. So thus, he had to "pretty much piggy back off of the left rear door speaker".

How can you tell I'm new to this whole aftermarket sound system stuff, but what the hell does that mean? (i.e. can someone explain to me what actually he did to my car?) And, is that true of the 2002 p5 stock head unit???

Either way, it works, that's all I know. The sub's going, sound is sounding better.

 

[Poseur]

Basically there's 2 types of outputs on an aftermarket stereo. just about the same as a home stereo. One being the powered speaker-output that runs directly to your speakers, and one being the "RCA" that coun can use to send th audio signal to another component. Factory decks just about never have RCA jacks as it's kind of an aftermarket-only sort of thing to do. Now in a normal aftermarket stereo situation, you run an RCA cable from your deck to your amp. This not an option on yours, you simply have to take the Output from the existing signal to feed into the amp. In this particular ase, he chose to take that signal from your left rear speaker to then amplify and send to the subs.

 

[NothingFlashy]

Thanks!

Marshall above is talking about some output that connected directly from the head unit to the amp he has powering his sub. And from what I get, he's running the stock deck and head unit too!

So, I was wondering if anyone knew for sure if this output for the HU to amp exists in the stock HU. And is this the "RCA" output? Or some other one. (boom03)

Thanks

 

[1sty]

Thanks!

Marshall above is talking about some output that connected directly from the head unit to the amp he has powering his sub. And from what I get, he's running the stock deck and head unit too!

So, I was wondering if anyone knew for sure if this output for the HU to amp exists in the stock HU. And is this the "RCA" output? Or some other one. (boom03)

Thanks

A deck and a head unti are the same thing.

Some amplifiers have speaker level inputs so they will except the speaker wire outputs of a factory radio directly.

There are no RCA style outputs on the factory radio.