i ran them sonys off a sony xplod amp giving them there recommend power and no matter what i tuned them too they sounded horrible and they finally blew. they lasted for like 6 months and they are not bad budget woofers because they can be bought at walmart cheap but they aint god's gift to caraudio. i don't know about sony HU or coaxials but there amp and subs where terrible and that **** 300 watt rms amp wore out my alt. too. do you work for sony?
Something certainly sounds a miss if your alternator failed specifically due to a 300W load. Most OEM alternators would have little trouble dealing with that type of power. Hence why I mentioned the possibility of user error before.
Otherwise, it sounds like you simply didn't spend enough time tweaking them.
A typical Xplod 12" in a sealed 1ft^3 enclosure crossed over at 60-70 Hz with about 150-300 watts of power to it can sound pretty darn good.
No issues either with their HU's or amps.
In fact, I currently run a Sony CDX-M630 HU in one of my cars. Been using it for over a year now....
I have ran everything from Pioneer, Alpine, Eclipse, Becker, Panasonic, and the on... The CDX-M630 is certainly one of the better HU's that I have owned.
No, I do not work for Sony. I simply have been involved in Car Audio, and Car Performance for quite a while; and have decent exposure to many products.