# Can I use car subwoofer with my home system?



## wgreene

I have a really dumb question. Is it possible to somehow adapt a car subwoofer for use with a home speaker system? If so, would it be worth the time and trouble? 

A friend told me I should upgrade my home theater subwoofer in order to get a higher quality bass response. I happen to have a Bostwick HD Pro sub which was previously used in my Honda minivan and is now taking up space in my house. It seems that I paid at least several hundred dollars for it, so I figure it should be of higher quality than my Definivitive Technology ProCinema 60 subwoofer. I would greatly appreciate hearing from anyone able to answer my question. Thank you very much.


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## kiwiguy

Just check what you are driving it with, if you mean the woofer speaker on it's pwn without the sub amp from the car (which would need a massive 12v supply...)

The impedance is probably a little low at 2 or 4 oms, but if that matches the amp specs that you will be driving it with, it should be fine.

Typical home systems are 4 or 8 ohms.

But I do feel sorry for the neighbours.


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## tdi_veedub

As long as your amp can handle the 4 ohm impedance, it will work. If your amp can only handle an 8 ohm impedance, you can take 2 4 ohm subwoofers, connect them together in a series circuit, then you will have 8 ohm impedance.

The best subs to use are car subs, bar none. I feel sorry for any pictures, or other things hanging on your walls  Forget about the neighbours, you won't be able to hear them anyways


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## wgreene

Thanks, fellas -- that's what I needed to know!


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## Jedi_Master

Howdy folks...

wgreene...

As was stated above if your amp will handel it sure...

Just one piece of advice from experience, keep it away from the PC or any floppies, the car subwoofer is unshielded, which means that the big magnet on the subwoofer will have the possibility of damaging the hard drive or any floppies next to it ...


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## wgreene

Thanks for the helpful advice -- that's certainly important to know!


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## Chris Y

I Have the same problem too.....
I need to know how to connect my car sub woofers which i had in my mitsubishi..........
They are 2 12" Pioneer Sub woofers with Panasonic 1200 Watt 2 Channel Amp (Model#CY-PA2003U) and a Volfenhag Capacitor.......I need to know what i need in order to connect my subwoofers with my rca wires.......
I dnt know what type of power supply i need or whatsoever.......
Can U Keep help me out with this problem>??


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## Chris Y

I Have the same problem too.....
I need to know how to connect my car sub woofers which i had in my mitsubishi..........
They are 2 12" Pioneer Subwoofers with Panasonic 1200 Watt 2 Channel Amp (Model#CY-PA2003U) and a Volfenhag Capacitor.......I need to know what i need in order to connect my subwoofers with my rca wires.......
I dnt know what type of power supply i need or whatsover.......
Can U Keep help me out with this problem>?? It also has a 4 Guage Wire....as well


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## Chris Y

I Have the same problem too.....
I need to know how to connect my car sub woofers which i had in my mitsubishi..........
They are 2 12" Pioneer Subwoofers with Panasonic 1200 Watt 2 Channel Amp (Model#CY-PA2003U) .... I have a 4 Gauge Wire and a Volfenhag Capacitor.......I need to know what i need in order to connect my subwoofers with my rca wires.......
I dnt know what type of power supply i need or whatsover.......
Can U Keep help me out with this problem>?? 
If u wanted to know i was going to connect it into my Computer Speakers with Speaker/Subwoofer Inputs


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## kiwiguy

Jedi_Master said:


> Just one piece of advice from experience, keep it away from the PC or any floppies, the car subwoofer is unshielded, which means that the big magnet on the subwoofer will have the possibility of damaging the hard drive or any floppies next to it ...


Floppies, yes but you would have to insert the hard drive right inside the speaker and even then loss of data from it would be doubtful!



Chris Y said:


> I dnt know what type of power supply i need or whatsover.......


You need a power supply capable of *100 amps *at 12 volts.
I simply can't imagine where you will find a power supply with that rating that would be affordable - or even available.


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## Chris Y

Im guessing its pretty rare to find a 100 Amp at 12 Volts Convertor....
To tell you the truth i really dont know what that means or what it looks like.....
If you can help can keep me posted......because i really want to connect it .......it takes a lot of space in my room....
:up:


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## kiwiguy

When you find the 100 amp supply, then come back.

I have never seen one for sale, and remember that you do not want a "battery charger" it must be a smoothed DC supply.

Start thinking serious $$$$ as well, if such a supply is available.


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## Jedi_Master

kiwiguy said:


> Floppies, yes but you would have to insert the hard drive right inside the speaker and even then loss of data from it would be doubtful!


Don't know about that...because I actually had it happen to me several years ago, and I can tell you the symptoms you will see before the drive finally goes kaput ...

1) Drive will start becoming fragmented very often...
2) CRC errors when trying to access files (lost data)...
3) When trying to format and reinstall, numerous errors resulting in chucking the drive and getting another only for it to happen again, then smacking self in the head and moving the said speaker and getting a new drive...

Also I ran mine off a Pioneer 100 watt Stereo house recvicer...


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## kiwiguy

http://www.unix.org.ua/orelly/networking/puis/ch12_03.htm (and many other similar links exist)
"modern hard disks are becoming remarkably resistant to external magnetic fields. Within a few years, even large, military degaussers will have no effect against high-density disk drive systems."

The magnetic field from a permanent magnet speaker is almost wholly contained within the speaker voice coil area in the center of the speaker, or the speaker would be extremely poor in performance.

I suspect your experience had other causes than the speaker magnet proximity. The magnetic effect falls off according to square law, not linear, so extremely close contact would be needed.


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## Jedi_Master

Listen...I'm not going to get into a tit for tat with you...

I know what happened to me as a result of putting unshielded high wattage speakers near the pc...

And...I'm going to keep telling people to keep them away...


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## eaglewarrior86

I have a similar question about car subwoofers being used in a home theater system. I talked to a professor at my school who has a Ph.D in ECGR and he said besides the power supply the only thing I needed to worry about was speaker impedance. Most home theater amps, as someone noted, are stable down to about 4ohms, but not down to 2. I'm fine so far, in fact, I've wired my dual voice 12" Alpine Type-S to run at 8ohms for stability, but now my problem is the power supply. 

The problem is that my home theater receiver only has a pre-amp output for a subwoofer, so I don't think I can power my speaker through the receiver itself. I have a mono amp for my subwoofer I use in my truck, which I think runs at 12V--someone already mentioned something about that, I believe. How can I set this up to run in my house exactly? Has anyone actually done this using a car amplifier, and if so, what will I need to do? 

Thanks in advance,
Ben


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## kiwiguy

You need a sub-amp, such as "the one in your truck"

The sub-out from the home theatre would go into the input of the sub amp.

The subwoofer speaker unit connects to the output of the sub amp.

You then need the expensive power supply to power the sub amp from the AC mains.

Sounds simple. But certainly not cheap.


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## javer

a dirty way of making this work is a car battery parked beside the amps and constantly charged with a inteligent control charger, it will allow you to play 3-4h on a full charge unless you go full volume


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## kiwiguy

As long as the charger is HF switchmode, as recified 60 Hz would put too much hum on the line, I suspect. Plus, who wants a "container of acid" gassing in the lounge!


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## javer

well the battery is hardly going to gas if you use a closed lead acid, or a gel/solid state, also if you dont flatten the ripple on the 50-60hz i can tell you that amp will fry or not produce any sound at all, most amps demand that the voltage is stable at end stage before they allow the mosfet transistors to turn on and if it ever dips more than 5% up or down the relay will cut off entire end stage+drivers to protect against significant voltage spikes in relation to startup/shutdown

You can try using pure charger with a big capacitor(expensive and likely to have major issues due to voltage rippling producing unstable end stage voltages), or you can use a battery as capacitor/supply and be done with it

my education is aimed towards doing service on tv's/amps/computers, and i now work in IT department as the senior tech


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## alekovuterakos14

Does anyone know how to hook a car subwoofer up to home theater system? I already have one powered subwoofer in it but i cant figure out how to install the car sub. It is 10" bazooka.


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## bpinecone

Does anyone have any experience using professional or dj amps to power car subs? I am trying to decide whether its worth it to build my own sub for home use or buy one. Watt for watt these amps are much cheaper than home amplifiers and don't requre expensive ac/dc converters. Also they are routinely built to handle loads as high as 2 ohms. To me that seems like the logical choice for powering a car sub and I am surprised no one has mentioned using a pro amp.


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## Soundy

javer said:


> well the battery is hardly going to gas if you use a closed lead acid, or a gel/solid state, also if you dont flatten the ripple on the 50-60hz i can tell you that amp will fry or not produce any sound at all, most amps demand that the voltage is stable at end stage before they allow the mosfet transistors to turn on and if it ever dips more than 5% up or down the relay will cut off entire end stage+drivers to protect against significant voltage spikes in relation to startup/shutdown


Uh... have you ever measured the voltage of a car electrical system over time? Down to 11V running the stereo with the engine off... up to 14.5V with the engine revved up... that's a 30-40% variation in voltage, and car amps have to be designed to deal with that on a regular basis. A 5% ripple is less than you'll get just turning on your head lights.

And yes, sealed lead/acid batteries WILL release gas. Hydrogen is a byproduct of charging them, there's no escaping it. Even "sealed" batteries have vents to release the pressure.



> my education is aimed towards doing service on tv's/amps/computers, and i now work in IT department as the senior tech


Oh be afraid...


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## Soundy

bpinecone said:


> Does anyone have any experience using professional or dj amps to power car subs? I am trying to decide whether its worth it to build my own sub for home use or buy one. Watt for watt these amps are much cheaper than home amplifiers and don't requre expensive ac/dc converters. Also they are routinely built to handle loads as high as 2 ohms. To me that seems like the logical choice for powering a car sub and I am surprised no one has mentioned using a pro amp.


Well, the LOGICAL choice would be a sub properly designed for a home system to begin with, but if one INSISTS on using a car sub in the house, there's no reason a PA amp won't work to drive it.


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## kiwiguy

The PA amp will often not be designed to supply the very high power levels at the very low frequencies though, as the car sub amp is. So the useable Watts will be lower than the PA rated watts. But that should make the neighbors happier...

Puzzled by your reference to "loads as high as 2 ohms", I hope you mean "loads as low as 2 ohms"?


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## Soundy

kiwiguy said:


> The PA amp will often not be designed to supply the very high power levels at the very low frequencies though, as the car sub amp is.


Really? So what do they use to drive the subs in PA systems?



> So the useable Watts will be lower than the PA rated watts. But that should make the neighbors happier...


WTF is a "PA rated watt"?

PA amps are no different in basic design than a home amp. They're generally not as pretty and they're designed to take more of a beating because they get moved around and generally operate in harsher environments, but the amplification concepts are no different.


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## bpinecone

> Puzzled by your reference to "loads as high as 2 ohms", I hope you mean "loads as low as 2 ohms"?


I did mean "high." The lower the impedance of a speaker, the more current it draws. Thus the load on the amp is higher. If you are confused by this concept, consider Ohm's Law: I = V/R. If the resistance or impedance (R) is lowered, and the electric potential (V) stays the same the current (I) will increase. This is why its possible to fry an amp by hooking up speakers with an impedance that is too low. This is also why a stereo amp that is rated as low as 4 ohms can typically only operate as low as 8 ohms in mono-bridged mode.


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## kiwiguy

Thanks for the lesson!

As an electrical engineer, I am quite conversant with Ohms law...


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## kiwiguy

Soundy said:


> Really? So what do they use to drive the subs in PA systems?
> 
> WTF is a "PA rated watt"?
> 
> PA amps are no different in basic design than a home amp. They're generally not as pretty and they're designed to take more of a beating because they get moved around and generally operate in harsher environments, but the amplification concepts are no different.


You use the term PA amp without reference though.

A "real" "Public Address" (PA) amplifier is nothing like that used by a DJ. Two different species. A PA amp is used in places like lecture hall, sporting events etc. The output is usually more in the higher frequencies for efficiency of hearing speech related content.

The PA rated watts referred to was the total rated output of a PA system, where the low frequency power will be a very small fraction of the deliverable wattage. You cannot force such a general purpose amp as a PA system to only deliver the watts to a sub, as low frequencies.

And yes, I have maintained and installed "PA" systems for sporting events and the like.

I think you meant something other than a Public Address system?


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## Soundy

What you're talking about I think would be more like a PA "receiver", with multiple line and mic inputs. The amp's output itself is rarely frequency-limited; the mid-band emphasis is more often than not simply provided by a built-in EQ. Unless it also has a built-in high-pass filter, the AMP portion will deliver just as many watts at bass frequencies as anywhere else in the spectrum... which in the case of most voice-centric PA systems isn't a huge amount to begin with, since it's not necessary BECAUSE you're normally only driving a limited frequency range.

The concert sound systems I've dealt with are ALSO known as "PA systems"; the amps used to drive them are ALSO known as "PA amps". They DON'T have multiple source inputs and built-in mixers and EQs.


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## coolraul

hey guys,

a relatively cheap way of getting a 12v source for a car amp is to use a computer power supply. Here's a quick summary of how to turn on a computer power supply manually if it's not connected to a computer:

http://www.techpowerup.com/articles/other/22

more:

http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

the 12v line is one of the yellow ones. You can find these power supplies either from cheapie throw away pcs or from the internet depending on how much juice you want, for example, Newegg has one with a 12v line running 20 amps:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817714001

I used to ghetto rig a used pc power supply box to a pair of auto 12" subs in my dorm room back in my undergrad dorm. I put the subs facing the wall underneath my bed, dear g*d, the walls shook and everything on my desk danced. I laughed when my friend down the hall mentioned that he thought dinosaurs were wandering outside...

please lemme know if that helps, does anyone know if any manufacturer has pre-built sub box/amps so that one can plug and play a sub of their choice?


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## coolraul

abcd


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## olib007

Most car amps require a power feed from a car headunit to turn them on, how would you overcome this?


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## coolraul

You can tie a 12v line (a yellow wire) from a computer power supply to the "turn on" line from the amp to turn it on . I believe most car amps require 12v to the "turn on" line.


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## Soundy

The turn-on signal is just +12V. Connect it straight to the main power feed with a switch.


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## Greg7456

Ok so I am a complete newbie at this,

I am trying to hook up my car sub and amp to my stereo. I know I just plug the 2 rca cables into the back of the stereo, and the black connects the amp to the sub. I believe the red is the power to the amp. I need to know where the red one goes and how to connect it, as well as the brown. I'm assuming somewhere in the comp. power supply but I'm not sure exactly where. I really don't know what I am doing but I'm trying to learn, thanks in advance.


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## Soundy

Well first of all, you should really start a new thread for a new question...

The RCA cables are both for the audio signal - they go to the left and right outputs on the stereo, and the left and right inputs on the amp. They're usually red and black or red and white.

If you're using a computer power supply (NOT recommended, although it will work), you want to use the YELLOW wire on the power supply to the amp's power (+12V) connection, and black to the ground. You also want to connect to the yellow to the amp's "remote" connection (if it has a wire for it already, it will likely be blue).

The sub connects to the speaker outputs of the amp, but as far as what color wires it uses, there's no way we can tell what your setup uses.


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## Greg7456

Ok, so if I am using a computer power supply, does it matter how many watts? I am using an MTX amp that is pushing 270 watts rms, and a pioneer sub that can handle around the same amount of watts. So my new question is what specifics do I need to look for to make sure everything will work fine. 

Also, my amp currently has a red wire running to it's power. Will I be setting this aside and not using it at all, and be using the yellow in it's place? Thanks.


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## Soundy

Take a browse through these site and get some basics of car audio first...
http://www.bcae1.com
http://www.the12volt.com


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