I’ve come to think that the subwoofer connected to the receiver on my dad’s home entertainment theatre system thing is weak. However, I and my dad agree that the ones in my car are a lot more powerful–a lot! So what I had planned to do (when i get sick and tired of bass in the car) is to take the amplifier, a Rockford Fosgate 800a2, and 2 subwoofers, AlumaPro Alchemy 12", and hook them up to the receiver in the basement. BUT, the amplifier uses a 4 gauge wire (about as thick as my pinky finger) to power it with 12 volts. Although it has an 80 amp fuse in the line, i’m sure it doesn’t use 80 amps all the time.
So, is there any reasonable way to use a 12v source (in the home) that will supply enough amperage without using a car battery?
More elegant than a Sears Die Hard but just as ugly, get a few old ATX power supplies from junk computers. They have 12V rails which provide anywhere from 8-15 amps, depending on the size of the power supply. I’ve got a pair of power supplies in my garage that I use to run an old 250 watt car amplifier on my speaker test bench.
Pretty regularly on pricewatch.com, I’ve seen vendors selling power supplies in the $5-10 dollar range (although shipping costs often minimize any real savings.) So I have one of the IT guys at work who maintains the computer hardware send me power supplies from computers that are being decomissioned.
You have to figure out which wires supply 12V, as there’s also wires that supply 3.3V and 5V and not every manufacturer uses standardized coloring.
Be aware that many car drivers/bass boxes are designed to take advantage of the huge ‘gain’ available from the small size of the car’s enterior. In a big room they may not give you much bass at all.
Thanks Anthracite. That means a lot, coming from you.
Something else I’ve been thinking about using them for is to power some huge strings and arrays of LEDs, as Christmas lights to hang on my house and in the windows and trees in the yard.
I’m so sick of seeing the boring white icicle style lights that everyone uses. I want some color, damn it!
Okay, I wanted to try this (car subwoofer attached to a computer PSU) but have run into a problem: when the PSU I have is plugged into the wall it only supplies 5V. I assume the 5V is to power the motherboard and the main ON/OFF switch attached to the MB, which when pushed kicks on the rest of the power supply and everything else. Do I have a non-standard ATX power supply (it’s from a Dell so I wouldn’t doubt it) or is there some trick to getting the 12V part of the PSU to operate w/o a MB?
Uh, yeah. I forgot to mention that. There is one particular wire that you have to short to ground in order for the rest of the voltage sources to come on. Of course I can’t remember which one. And being away from the house this week, I can’t just go take a look either.
And yeah, the Dell power supplies are configured differently I’ve heard. I think they switch the arrangement of a few wires in the big Molex plug so that only Dell motherboards can work with Dell power supplies.
Better yet use a 12V USP and attach the amp directly to the battery - the USP will recharge the battery and could supply backup power to other parts of the home entertainment unit as well.
That might work k2dave, of course, but, you see, I don’t have a UPS laying around the house right now. Fresh out. I do have an extra PSU. I’m trying to do this with minmal capital outlay. If I was going to spend money, I’d get this and be done with it.
I assumed I had to supply something back to the PSU to get it to turn on. I just wasn’t sure if it was 5V or 3.3V or -5V or, as you say, ground. And not knowing which pin to use is also a problem.
A car amp that drives a woofer with any type of real authority is going to use way more current (for brief periods) than most 12 volt power supplies will be able to deliver.
It is quite likely that unless you spend quite a bit more money than you have in mind you will be quite dissappointed with the results.
If you do try this project, here are some useful tips.
Use a home amp to drive the woofer. Dollar for dollar you are going to get more power to the speaker, than you would buying power supplies and car amps. Also, there is nothing magic about a car speaker that would make it incompatible with a normal home amplifier.
Keep in mind what Rhum Runner said comparing the interior volume of a car to a typical room in a house. He is quite correct.
But, if your really wanted a high quality sub for your house, at least go find a place that sells the Velodyne HGS (remember HGS) and see what a competently designed home sub can do. This would be a good benchmark to shoot for on your project.
You indicate you are using two 12" subs, I would be willing to bet you will have a difficult time matching the performance of a single HGS 12. The HGS 15 and 18 are simply ungodly in what they can do.
One thing that I think you realizse is that you are going to have a setup that can provide very high current for very brief periods of time and have steady power input, that crys out for a battery or supercapacitor (but I doubt you have one of those lying around either).
I dont a PSU will provide enough current but then again it’s free.
You know, looking back, it appears that my post to you could seem snippy, k2dave. It wasn’t meant to be at all and I’m glad you haven’t taken it that way. I appreciate your suggestions.
scotth: I have a Kenwood KSC-WA801 powered sub, which has 8" drivers (and runs at 14.4V, not 12, I now notice – oh, well, 12 should be close enough for the girls I go with) and draws a maximum of 12A. The PSU I have outputs 6A at 12V, so one is kinda weak, but two will get it. Since all I’m looking for right now is proof-of-concept, one will do. If I have to get another PSU, I know where to get it for free.
I’m aware of the loss in sound “volume” I’ll experience introducing a car audio component into a larger space, but I’m not looking to shake the windows and send the cats running. All I really want to do is access the DTS soundtrack on the DVDs I watch. Heck, most of the time I have the sound turned down so low I have to have the subtitles on to understand what’s going on (I only get to watch movies when my 2-year-old goes to bed). So, why am I bothering with all of this? Because it’s there.
I was playing with a ATX PS a while back and remember having to simulate a load on the +5V (I think) in order to make it switch on. Memory is hazy but I think a 100 ohm resistor did the trick.
Also, if you intend to run a car amp off a computer PS at any higher levels of volume I highly recommend some VERY large capacitors to supply the surge current you will need. The caps I’m talking about are automotive audio caps. I would probably use alteast a 1 farad cap, maybe even a 1.5F. These things are big & expensive, but without it the PS will likely just shut down (overload protection) the first time you try and play something with bass.
Thanks for the help, everybody, but I decided to just wimp out and buy a home audio sub. Got one at Fry’s for $80.
I might still play around with the other one, though. My receiver accepts two sub inputs.
Call me an elitist, or snob, or just an ass monkey… but I think I would have a hard time listening to an $80 Fry’s sub. Those things are generally just plain bad.
It’s a KLH. Not outstanding, granted. Not even really all that good, most likely. But good enough for what I need right now. And probably better than what I was going to end up with going the other way.
And you may be an elitist and a snob. I don’t know about ass monkey (I don’t do smilies, but if you want, imagine the appropriate one here). It doesn’t really matter, though. You are certainly entitled to your opinion. And I appreciate you participation in this thread, FWIW.