connecting subwoofers

[luvgi]

Hi,
I have a car audio compatible subwoofer.anybody here who know how to connect this subwoofer to my hi fi?it has an inbuilt amplifier.can i cut open the end of any 12v adaptors to connect.i dont know if it fits a 300 ma,800ma or 1250ma.will it work with any of these.please ,if any experts can advice me on this .

[diydave]

You'll need a very big DC power supply to use your car subwoofer in your house. You can do a very rough calculation by dividing the wattage of the sub amp by the voltage of your supply.

If your sub amp is capable of putting out 120W, you'll need about a 12 volt, 10 amp DC supply. (10,000 ma). I'm not sure how efficient modern car amps are, so you'll want to add an additional 25% or so. DC supplies that big are rather expensive.

You're better off with a whole new kit.

[RobWells]

Use a couple of car batteries to power it (in parrallel), and charge them daily.

Hopefully you have all the right crossover components to integrate it properly ?

I really think you'd be better off building a proper home sub if you want decent sub-bass in the home.

Rob.

[AndrewT]

Hi Robb,
is that because the car fraternity cannot get past "watts is best"?
Or simply that car equipment is set up with a very high Q and so does not suit in room use?

[richie00boy]

Good quality car stuff is often not all that high Q, but the small boxes used means the F3 is usually too high for house use, but fine for cars.

[RobWells]

Richie pretty much answered for me

I've tried a few car subs in home over the years, and most had no low bass to talk of. Unless you've got the eq available to boost down low, then I think a 'home' sub will be better. Also a lot of the car subs I've looked into / used have pretty small x-max. (compared to home stuff)

If luvgi could get the t/s parameters for his sub then we could work out if the box would be ok for in the home or not. I'm assuming that it is a 'typical' 10" or 12" sub in a 'typical' 1.5cuft box.

I know I shouldn't have made assumptions

And yes I know there are some car subs out there that would make great home subs.

Rob.

[luvgi]

There is something i needed to add up.
its a 1000w with 12v.also has a 20A fuse.so i assume it works below 20A???

[BassAwdyO]

12volts X 20amps = 240watts

That 1000watt rating is a LIE!

[AndrewT]

Hi Bassawdy,
your simple assumption that max continuous input power (based on amperage) will equal or greater than the max (peak?) audio output might not be valid.
Take for an example the PSU line fuses feeding the output stage of a SS amp. They might be F5A but the output stage could deliver maybe 4 or 5 times this as a peak current and some very short signals could be even higher.

[bobo1on1]

Yes but you'll need a higher voltage for that, which will make a very inefficient class AB amp, so its only suitable for class D.