Audiobahn ACX692 6x9's?

You should be fine running the ACX692’s off of the head unit. You will not have any problems at lower volume levels. But what happens is at higher levels your head unit starts to max out and instead of pumping out clean power it will put out distorted power. Distortion is what blows speakers not too little or too much wattage. So at higher levels if your speakers start to distort just turn it down a little and you should be fine. If you want to be able to get more volume out of them with out them distorting then get an amp. µThose speakers also have an outboard X-over so be sure to adjust it for best sound. On some systems it sounds better in full range and in some it sounds better in high pass so try both modes and then choose which one sounds best to you.