[CinemaSound7]

Just wondering. There are some really cheap (and powerful ones) for sale used online. I have a few 12" drivers sitting around, so I thought before I do my 18" DIY subwoofer maybe I could buy a cheap one and make a "test" subwoofer before I spend the money to get the real parts for my DIY.

 

[Bill Fitzmaurice]

Car subs are designed for use with music in a 125 cu ft space, not HT in a 1500 cu ft or more space. Some auto sound drivers may work for HT, you have to software model them to be sure.

 

[Gary147852]

Just wondering. There are some really cheap (and powerful ones) for sale used online. I have a few 12" drivers sitting around, so I thought before I do my 18" DIY subwoofer maybe I could buy a cheap one and make a "test" subwoofer before I spend the money to get the real parts for my DIY.

I would say to do all the experimenting, researching and practicing you can before you jump into a build. You can use a car subwoofer amp, you'll need something to take you from 120vac to 12vdc(car battery charger) to power the amp. As bill said, in order to determine whether the driver will work well or not it has to be modelled.

It would also help to know the model of the amp you plan to use that way we can determine if it has a hi pass filter

 

[CinemaSound7]

Thanks to both of you for the advice! Maybe not such an easy thing, maybe just better for me to buy the proper amp from the outset.

Thanks.

 

[BassThatHz]

Thanks to both of you for the advice! Maybe not such an easy thing, maybe just better for me to buy the proper amp from the outset.
Thanks.

This is a very common budget-oriented high-power amp used for subwoofers.
http://www.parts-express.com/behringer-nu3000dsp-inuke-3000-watt-power-amplifier-with-dsp--248-6706



You could build your own DC power supply with a Variac or big 15V toroid, a high power bridge rectifier circuit and a big capacitor.
http://www.ebay.com/itm/Variac-Vari...C-with-Meter-TDGC-3KM-Max-30-amp/161613736322
But if you die while building this electric chair, don't say we didn't warn you...

The problem is you'll be current-limited.
Car amps require 14-15volts, where as the HT subs operate off of ~200VDC after being converted from 120VAC. When you are limited by a circuit breaker, the more volts the less current needed to make X-watts (it is Ohm's Law).
By a factor of about 10X!!!

 

[Gary147852]

Thanks to both of you for the advice! Maybe not such an easy thing, maybe just better for me to buy the proper amp from the outset.

Thanks.

My current setup.

Atx psu capable of 400 watts. 22 amps supplied to the 12v rail makes a total of 264 watts powering a xm-sd46x Sony car amplifier. Running the sub out from my receiver to the rear channel input on the amp, running in bridge mode pushing 150 watts to my 4 ohm kicker. Gain on the amp set to accept a 1 volt signal. Low pass filter set to 110hz, no bass boost, x-over on my avr set to 80 hz. It's a 1ft3 enclosure tuned to 25 hz.