Im toying with the idea of upgrading my speakers but know little about how it all works so hopefully
someone can give a little advice..

For the front speakers is it possible to buy 2 or 3 way speakers and then replace the dash tweeters separately rather than buying splits?

I dont even know if that makes sense tbh haha

I did this a few weeks back, since the existing speakers are splits (and not bad ones at that) it'd would be best to replace them with splits. putting 2/3 way speakers in the door will just mess up the sound staging. I replaced the front speakers with Hertz HSK165's and its not really a small feat.

What sort of improvement are you after,price etc?

$250 for the fronts and $250 for the backs so about $500ish give or take... i just want a cleaner sound and to be honest wont have them blasting as i dont want to look like a tool...

so you think even if i still have the tweeters running on the dash aswell as having 2/3 ways in the doors it will throw the sound out?

Having coaxial speakers in the doors you will sorta be able to tell that the sound is coming from the doors. Of course not all speakers or peoples hearing is the same but from my limited experience that's how it works. If you unplug the passengers door speakers and play with the h/u fader and balance so that its panned to the front left you'll find the stock tweeter is very quiet.

IMO If you are going to upgrade the speaker may as well do it right. For that kinda cash I'd recommend getting an amplifier with High-level inputs and upgrading the front splits.

EDIT: this site explains it a bit better: http://www.caraudiohelp.com/newsletter/coaxials_versus_components.htm

unless your going to use an amplifier to drive the larger wattage speakers , stick with the low power ones you have now as they are matched well for the headunit output.
my first system was using a hi/low level converter off the stock GT headunit, then ran RCA's to the amplifier..

obviously a nice set of splits with a crossover network is much better than mix n' matching speakers and tweeters up..

Semi on-topic here, but I am thinking about building a Car PC. Audio output (I expect) would be via 3.5mm jacks from a USB sound card going direct to the speakers via an ISO connector to the existing radio connector in the dashboard. Would this even work, or would I need to go through an amp first?

It would be a lot easier to use a amplifier seeing as it already has RCA inputs. As for trying to connect it to the head unit you'd need to hack something like the iPod connector.

If keeping the stock headunit, you need to look for speakers (particularly the mid-range speaker if running splits) that have a high sensitivity rating i.e 91 dB or above. Stock headunits and some lower end aftermarket jobbies don't have the guts to power a decent set of speakers without an external amp. Running speakers with a higher sensitivity rating will improve overall performance, and the difference over stock speakers will be much better. No point sticking 150W RMS speakers in an otherwise stock setup if the sensitivity dB rating is low

Are there speakers with a high sensetivity rating that we know of?

I do know of this problem as I upgraded the speakers in my Falcon and it was terrible so I amped it. I don't want to add an amp to the 380, just a simple upgrage of speakers will suffice.

Infinity Reference components run in the 93dB range. This is above average, even a 91dB sensitivity rating will be good on a stock head unit

Cool, I'll check into those, thanks.

You'll have to make some custom rings/ baffles. The380 speaker intergates the mount and speaker as one, the speaker is lined up better than the magnas, but is set fairly well back, lots of sound rattles the doors like crazy,.
They seem like a rattly door.compared to a magna.
If you to on the volume knob a bit, or decide to amp them, I would -
If possible, raise the mount off the door, close to the hole in the card, deaden a lot, sound absorbent pads behind,and at least 250 mm of deadening around the speaker on the door skin.
I have high passed mine to get over the rattles.
Personally I would cheat and run a 10 - 12 sub off the high levels from the rears. The 380 system is pretty good for what it is, it just needs more bass.
The black SA 380(formerly qld)with the 22's, now sold, matt n carol, IIRC, I think did this and it was very good.
My 2 cents.

Whoa, sounds like a lot of work to change these over. I was hoping it was just unscrew and replace, like in the Falcon......may have to rethink it.

Just pull the doors off and take a look.

thanks for all the info guys...

im going to run everything through an amp as this seems the way to go... and to be honest i think im just gona get an installer to do it all properly. ill just let them know about all the little niggles and the rattling problem and leave it to them..

im thinking about getting some rockford fosgate power series 6.5 splits in the front and 6x9 same series in the back... anyone had any experience with these or similar??

It's all been done before here (http://www.aussiemagna.com/forums/showthread.php?t=54382&page=1&highlight=Rockford)
I know Knotched upgraded too, to what I can't remember, but his is amped too.

just got a double din gps/dvd unit and im gona have a go at installing it myself but im not too keen on cutting and connecting wires so i was looking around for a harness and found one on ebay... would it suit a 2005 380? it says iwill suit a galant up to 2006 but still not sure if it will be a complete match?

the other thing that is getting to me is that theres a note saying "This lead is for the NON-AMPLIFIED systems on these vehicles only.".. not sure what this means..