Hey guys, I have two 12 inch subs from my WRX that are just not practical to put in the trunk of my Gcoupe. Anyone know if it is possible to take the two 12s with the amp and somehow connect it to my 5.1 system in the house? If so, what would I need to do? Thanks for the imput.

 

You need to figure some things out first.

What ohm rating does your 5.1 receiver expect to see on the subwoofer channel? Most likely 8 ohms, though some receivers have a switch to change to 4. You'll need to wire your subs' voicecoils properly to present the proper rating.

You'll need to figure out what wattage the receiver can put out on the subwoofer channel, and see how that compares against your subwoofers' ratings.

--- OR ---

You can try and get a 120VAC-to-12VDC power supply with enough amps to power your 12v car sub amplifier, and run the subwoofers off of this. This would require you to figure out the amps the amplifier draws and find an inverter/power supply capable of outputting that. If your sub amplifier does not have high-level inputs (speaker level), your 5.1 receiver would then also need a non-amplified output.

----------

That being said, it's going to be expensive to find a 120VAC-to-12VDC power supply / inverter with enough amperage to power your subwoofer amplifier. And I don't think a 5.1 home theater receiver is going to have enough juice to power the subs directly. And 120VAC home amps are expensive too.

That's not even discussing the different speaker designs of home subwoofers vs. automotive subwoofers. All in all it will be cheaper, easier, and better quality to buy a home theater subwoofer than to try and do what you are thinking about. And I realize you probably already have a subwoofer, and you're just looking to add these as extra.

 

I beg to differ. I'm lightly in diy home (and car) audio. Just as an experiment, and after doing some research, I decided to use a Sony Xplode 10" sub, about 2 years old, that I had laying around, as a diy subwoofer project.

I've never been a fan of any kind of subwoofer system with a port (except Transmission Line systems, but my wife did not want a new piece of furniture in the living room ), so I made a simple sealed box, about .7-.8 ft3. On the back of it, I mounted a plate amplifier, capable of 150W RMS into 4 ohms. I know this doesn't seem like a lot, but it does the job extremely well. I bought the amp off ebay for $75. I has a continuously variable crossover, non-switchable bass-boost @ 40Hz, and has a pretty good damping factor.

I put the box together using good ole' 3/4 MDF, mounted the sub in a down-firing position, using spikes to raise it off the floor, and covered the box with silver colored adhesive vinyl to match the rest of my system/decor. The spikes and vinyl came from PartsExpress.com.

All I will say is that I am so impressed with it, that, six months after building my "experiment", I have no plans on changing it any time soon. It is clean, relatively tight, and has plenty of amplitude for my purposes. It also, and this is not just my opinion, sounds better than a lot of $200-$400 subs that I have demoed from "high-end" makers (lol) such as Polk, Klipsch, and Infinity. One more thing, my single sub is being used in a room that is 45x15 with 14' vaulted ceilings - a very large room to fill with sound.

The only thing, and this is mostly due to the large space of my living room, is that there are quite a few dead spots. Since they are not in any of the primary listening areas, it doesn't bother me.

If you do want to use auto subs, this is no joke, use the cheap subs of a good manufacturer. By cheap, I mean the lower end line of a good sub maker. The main reason is that the cheaper subs are usually not designed to take advantage of a vehicles transfer function, which is basically described as the effect that a small sealed cabin (your car) has on low frequency waves. Using the cheaper subs will yeild a better frequency response inside a home.

For more info, check out diysubwoofer.com, diyaudio.com, and partsexpress.com.

Good luck!

 

so what did you use to power the amp and subwoofer? Were you able to plug the amp into a 12v wall outlet?

 

Sorry, let me clarify. I bought a home audio subwoofer - like what you see on the back of any self-powered subwoofer you'd buy at a store. It is made for the home, so it has a 120V AC power supply and a regular power cord to plug into a socket. Look at www.partsexpress.com or www.madisound.com or even ebay. Do a search in the home audio area for subwoofer amp or subwoofer amplifier.

Trust me - you can, with minimal skill and experience (if you take your time), build a subwoofer that will sound much better than what you could buy one in the store for, given the same budget. Considering you already have the subs, get a really strong amp (250+W RMS) for each sub. If the subs 4 ohm (most likely), you'll probably need to run 2 separate amps - if your subs are 8 ohm, use one amp and run your subs in parallel. Either way, make sure the amp you get is 4 ohm stable; most are. I would recommend building two completely separate boxes and experimenting with the positioning of each box until you find the "optimum" sound for your room/application.

 

I bought a sh**** KLH home sub at costco a few years ago and replaced it with a Velodyne 10" sub which I love. The KLH sucked until I stuck a JL 10W0in it thinking it might help a little bit, but was surprised that it sounded as good as it does. I was thinking of trying a home sub in the car, but the cost of the inverter is too much.

I don't know what this adds, if anything, just my 2 cents.

 

these are the specs of the subs I have:

Features
Speaker Type Subwoofer
Speaker Diameter 12 inch
Maximum Power Handling 700 Watt
Nominal Power input 175 Watt
Sensitivity 93 dB
Impedance 4 Ohm
Response Bandwidth 25 - 800 Hz

Mounting Depth 5.31 in
Mounting Diameter 10.87 in
Gold-plated connectors

So because they are 4ohms, I'm def going to need 2 amps then. It says normal power input 175w, so I should be able to find cheap home amps then I guess. I was running one 800w max amp in my car and it was able to work (my friend installed it all cause I'm n00b with electronics), so I'm confused as to why I could not do the same in home. Also, do you think it would be overkill with 2 12" subs in a 15x15 room?

also, if anyone is reaaallly bored, you could entertain yourself by looking up a cheap home amp that would work with this setup and then post it haha thanks guys

 

It will depend on the amp's capabilities as to how you need to wire the subs. Check out www.partsexpress.com and find a plate amp, like are found on a lot of powered subs. If the plate amp needs 8 ohms of impedance, then wire your two 4 ohm subs in series to make 8 ohms. Having two separate amps will add extra cost and complexity to the system.

 

Extra complexity, slightly. Extra cost, not necessarily. To get the same power output to two subs from one amp will usually require an amp that costs more than two smaller amps that are 4 ohm stable.

Example (from partexpress.com), using 250W RMS as the goal:

one Dayton Audio HPSA1000 (512 Watts MAX. into 8 ohms @ .094 % THD) = $398.80 - will supply 250W max to each sub

or

two Dayton Audio SA240 amps (240 watts RMS @ 4 ohms) = $128.88 ea x 2 = $257.72

There is no need to try to hook up 2 subs to one amp in an 8 ohm configuration. Any outputs received from the use of two subs will be virtually cancelled because you are cutting in half the amount of power to each sub.

Try using one sub/one amp first. If you want more, then do a separate sub/amp.

Good luck!

 

thanks guys!