Sorry for the epic story, but there are conclusions and a link to pictures at the bottom if you want to skip:
Wow. A long time ago (May 2004), I couldn't any information on putting PC speakers into a car. I even made a post that never got a reply. I was beginning to think it was unprecedented.
The true story is, I made a post in the power supply forums, and it was active (32 replies):
Speakers using a modified sine wave inverter
I remade that post in the Car Audio forum since it was large and delt with the actual audio rather than the power setup (0 replies, probably due to the fact that people just posted on the original post):
Speakers using a modified sine wave inverter
My original question was not whether the speakers would sound good, because they sound great in the house. I wanted to know if they would work with a modified sine wave inverter before I went out and bought one (modified sine wave inverter is /much/ cheaper than a true sine wave inverter).
I received many posts saying that putting PC speakers in the car wouldn't be a good idea, but I received very little evidence to support that claim (I even lashed out somewhat, stupid I know, but I don't enjoy statements that are not backed up with any evidence). True, I had no evidence to support that they would sound good other than the fact that they sound great in the house. I was certain, though, that they'd sound better than my stock speakers. I hoped they'd sound comparable to nice car setups for a /fraction/ of the price.
Soon after posting (in summer 2004) I had purchased a cheap 400W inverter <$30 and hooked it up to my car battery and tested the speakers (ran an extension cord for my desktop PC and monitor to test). They worked with no problem, I was happy.
In June 2006, I purchased a tablet PC (Toshiba m200 with external DVD drive and docking station). My intent was to use it for school, work, and leisure. I also planned to mount it's docking station in my car somehow to make my tablet my removable Car PC.
I accomplished that goal. I was using a tape adapter to the stock head unit for sound. I had mp3, dvd, iGuidance GPS, etc... in my car. I was happy.
For a couple months I used the tape adapter. I had been planning on using the z560s in my car since 2004, but never did it. I generally only listen to talk radio while I'm in the car, so car audio isn't that important to me (not important even to spend a lot of dough on speakers that I would rarely use to their full potential). One of the problems, though, was that I planned on plugging the tape adapter (or speakers) into the speaker jack of the docking station for the tablet, but there was a lot of hissing/noise coming out of the seakers when connected there. So I had to dock the tablet, then plug the tape adapter into the tablet each time I got into the car. I hoped that when I put the Logitech z560s in, they would get rid of that hissing.
I finally upgraded the Logitech z560s on my MediaPC / PVR to some Logitech z5450s (needed wireless surrounds...). So I decided to run a test with the z560s in the car. speakers -> inverter -> battery and they worked fine. I then went ahead and decided to test speakers -> inverter -> cigarette lighter and they still worked. I cranked them up louder than I would want to listen to them to make sure that the cigarette lighter would provide enough power without blowing the fuse (also, I'm only using the front two speakers, so less power usage). I also had the tablet on the docking station, charging (not running at 100% CPU usage though, which I should test). It all worked, I was happy.
This setup is not finished. There's still some work I need to do, more on that later.
I'm not an audiophile. I typically listen to talk radio while in the car (actually, downloaded talk radio so I can listen w/o commercials). I do have nice speakers for my desktop (z6800s) and media PC (z5450s).
1999 Ford Taurus SE, Toshiba m200, Logitech z560s
I have a toshiba m200 with a docking station in the car (I know it's ugly in the pictures, but it's quite functional). Logitech z560s are connected through the docking station.
Logitech speakers and toshiba m200 are powered through a 400W super cheap inverter (~$25) from ebay (has 2 plugs though, nice). I played the speakers much louder than I'll want to listen to them with the base turned up to a quite high setting to draw a lot of power. I didn't have any problems with distortion or power usage. Didn't blow a fuse either. That's somewhat strange because the cigarette lighter has a 20A fuse, so at 12V, that's 240W. I have only the front two speakers plugged in, and roughly that's a 300W RMS system (4.1 system 400W total; satellites ~50W, sub ~200W); also, the tablet is drawing some power. Anyway, I haven't had a problem with the power yet.
As I expected, the z560s sound MUCH better than the stock speakers.
I currently have them in the floor board of the car, you can see in the pictures where I had them originally (I have moved the one on the driver side to a slightly different location for now, but no change in sound).
As others have stated in this thread, the drivers on the front speakers are small. They don't provide a lot of bass. The sub provides plenty of bass. Luckily, I don't like a lot of bass. I have been in my friends' cars that have loud setups, and that does not appeal to me at all. Also, listening to talk radio (actually, with most things) with a lot of bass gives me a headache. I even keep the bass on my desktop PC speakers down very low.
When listening to music, I'm very pleased with the audio quality. These speakers sound much more "filling" than the stock speakers. I've only tested from the driver seat (and in the trunk, heh).
As for loudness, I already stated I can get it louder than I ever want. The bass can get pretty loud too; enough to shake the rear-view mirror and what not. It doesn't compared to the loudness of my friend's $1000 12" sub setup, obviously.
I can't comment on how well the speakers will hold up in the car when exposed to the elements. So far there hasn't been any problem, but that's with less than a month of testing and mild weather.
Bottom line: I purchase the z560s a couple years ago for $86. They have great sound quality, better than I expected. Definitely a good quality/price ratio. The quality isn't as good as my friend's car, but honestly, his isn't /that/ much better, especially not for the amount he's spent on it (like ~$1100 for the speakers/amps/wire (not including head unit)).
Serious audio? No. Damn good for <$130. Mainly, I'm happy--much more pleased than my original expectations--and that's the real bottom line.
LINK TO PICTURES:
Has how I made my docking station mount for the car. Also, the last four pictures are of the speakers and wiring. The wiring in those pictures was a mess.
I plan to put the speakers in a place where feet won't hit them all the time. The driver side is currently dealt with but only temporarily.
Finish cleaning up the wiring.
The hardware volume knob is behind the console right now, along with the inverter, so I'm going to set up some hotkeys for managing software volume (not the best solution I know, but I can still reach the volume control if needed).
Thinking about replacing the front speakers with car speakers that will plug into the Logitech amp.
I really want to find a way to make my cigarette lighter only turn on when the car turns on. Right now I have to manually hit a switch on the inverter to turn it off. (It has a small cooling fan that continually runs.)
I need to start a thread about my project like most other have, I think.