Amp and Preamp Questions

I have a JVC KD-HDR50 head unit powering four Pioneer TS-A6882R speakers and one Boss 600 powered subwoofer.

The speakers have a max of 280 watts, 50 watts RMS, with 2-preamp outputs.
The head unit has 50 watts max with 20 watts RMS.

What's the purpose of a preamp?
Would it behoove me to still get an amp for this system?
With only getting 2-preamp outputs, does that mean two of my speakers are getting it and two are not?
Do I risk damaging my speakers (via under-powering them) if I don't get an amp?


Thanks.

 

From the link you provided for the headunit, it looks like it has speaker preamp outputs and a subwoofer preamp output. Meaning 4 different RCAs. The speakers will not get damaged by underpowering them, that would be like saying everytime you turn the volume down ur hurting the speakers. If it was me, i would power the speakers with an external amp and get a different subwoofer. Boss isn't really a good brand, it's among the lowest quality.

 

Ok, so I still have room to add an amp if I wanted. Good. That was my concern.

Thanks. I've heard conflicting information regarding this.

My truck will only accommodate a very low profile sub. I experimented with other wedge-designed subs and it still wouldn't fit without cutting into the truck. The Boss is not excellent but it does the job. I don't need to vibrate the windows out of the door panels.

 

I think i know where you're coming from. Having an amplifier that puts out less RMS (keyword RMS) than you're subwoofers RMS makes people think that they can crank it up all the way without hurting the subwoofer. This, however, is false as when you turn it up all the way, the amplifier sends a clipped signal (squared instead of round) and the power gains can be tremendous.

Here's an example...
You have a 200w RMS amplifier.
Your subwoofer is 250w RMS.
You crank up the amplifier as much as it can go with the gain and the bassboost thinking it wont harm the sub since it's only 200w. Now your amp instead of making a nice 200w sine wave, it makes a 400w square wave. That will damage the sub eventually leading to overheating the coil and blowing it.

There's very nice shallow subs in the market. Pioneer makes some, but the one that i would recommend the most is the Stereo Integrity BM (baby mag). Here's a link to it: http://stereointegrity.com/bm.php