I have a 10" BOSS Sub sitting in my room. Why do I need an amp to runt he sub? Why cant I hook the speaker wire directly onto the sub like a normal speaker?

You could, just it would be bad for your sub and its health.

You see speakers have an RMS value, which is the wattage that they like to opperate at. Opperating under this can "burn" them whilst operating above it can blow them.

Your headunit puts out aprox 14watts rms on average, and can only handle one speaker per channel, and is un-bridgeable as it can generaly only handle 4ohms resistance.

This is where amps come into play, if you have top end speakers like.... alpine type r components, then they are 70watts rms, so you will need an amp that can power to this level, so you would have to run rca's from headunit to amp, and then cables from amp to speakers. the best idea with this is to get a 75watt rms or 100watt rms per channel (2 channel if only front, 4 channel if using in back and front) amp and turn the volume control on it down a bit. Cause this way you limit the chance of under powering.

Your sub how ever is going to be somewhere between 100watts and 3000 watts rms depending on what type... your would be down the bottom of this scale though as its a BOSS. so basically your going to need something that can put out your rms power at the specified resistance rating. your sub might be a 2 ohm or 4 ohm, your going to need to find that out, as amps put out different power levels depending on the resistance rating and the voltage from the battery. The best voltage to look for is 13.8v cause thats aprox what your battery should be putting out while its on charge **ie car running**. 14.4v is un-realistic, so any figures you see at this voltage will actuley be lower in real life. and any figure you see at 13.8v will be lower when the car isnt running. so you will need to know things like that.

But basically the reason you cant just plug them both together is cause it will blow the amp in the headunit or "burn" your sub.

i think thats it.... if anyone wants to correct me feel free to btw.

So its possible just hihgly recommened not too?

all i can say is if you do it, its only a matter of time before either the sub dies or the headunit..... and it could be only an hour or so before one of them dies.

oh and besides that, the sub wont be loud at all

yes your sub would be severely underpowered and as soon as you turn up the volume if it will even let you your sub with either spaz out and crap itself or you'll f**k ya head unit.

Head unit arent designed to run woofers....amps tho can be picked up rather cheap tho...if u just wanna run a sub without worrying to much about how much grunt you can supply it with then just get a cheap s**t jaycar one or sony explode.