Originally Posted by Jerry Bransford
Just to be contrary, I am of the school that mediocre OE speakers will continue to sound mediocre with even an excellent amplifier. A sound system will never sound better than its speakers. The current speakers were designed to work around the power limits of the OE amplifier so adding more watts isn't likely to help much at all. I've been an audiophile/electronics guy since the 60's so I've heard all the arguments.
Actually, I'm right with ya on that one Jerry...
OE Systems are either too mild to show a noticable benefit, or too specific to easily be melded into (the Infinity 6-ohm Grand setups come to mind). So generally, you're best upgrade all around is both. But doing one or the other:
Replacing speakers, you'll get a better SQ potential from the paper OE fluff they put in, but still limited to OE power and source potential.
Replacing source, you can usually get more power (sometimes even as much as from 5-7W to 15-20W RMS) which can increase the potential perceived volume possible from the unit, and you can usually, on better units, shape the sound a bit more to also help a little with SQ. But you're still playing it through OE paper fluff stuff...
The catch here is it can become vehicle specific to which way is better if you must limit to one or the other. In stock non-upgraded Jeeps with their whopping 7W of output, people are more likely to notice the benefit of a new source. However, the OE speakers are not meant to handle much over that also so you're effectively overloading them... However, if they fail... really... so what... By then hopefully you can swing $50 or so for some good budget replacement speakers all around.
In the end, neither one is going to blow your pants off. You have to pick SQ over SPL if you're going to limit to one upgrade. (I also did my speakers first way back when... but tend to wait and do a fully planned install all at once.) But if you know exactly what source you want, you might be happier with that simply because it then does the options and features you want. So...
There's a bit more to it that which one is simply better. It's which is better for what reason for what scenario for what person. Generally, you're going to hear 'head unit' (source). But being an SQ extremist, some of us will do speakers first, or all at once. In the end, your system is only as good as it's weakest link.
You can put a Viper engine in a Pinto... (like putting a new source unit in a stock system) But if you don't put the whole drive line in with it, it's going to explode. On the flipside, you could put the whole Viper driveline on the Pinto engine and it will run fine, though overkill extreme. Little harder to push (same thing as putting powerhouse speakers on a stock or mild aftermarket source) but as long as not abused, would last forever. OR you can put them both in, engine and drive line (like putting in source, amps and speakers) and have the scariest Pinto in history. How's that for a different way to look at it?