Questions about my new system and underpowering speakers

Hey guys, I have a few questions about my system. So this is my first time changing out a stock audio system in a car with brand new parts, yes noobie here . The parts I have alrdy ordered are a set of Alpine type R 100 RMS (coaxial)6x8 for the front two speakers. For the back I have Alpine type S which are 75 W RMS(coaxial 6x8). I ordered a Sound Ordnance M-4075 amp which delivers 75 w rms to 4 channels. I also use an alpine cde 141 head unit.

So, im starting to question my choice of purchasing an amp with only 75 W rms, when i will be installing speakers that have a 100 rms rating. I have read that this can cause my amp to clip the tweeters heating them up and eventually blowing them out ("underpowering" them). Is this true even if I don't crank up my amp at all? In other words, if I just keep my amp at the normal settings (gains ect..) then my amp will not be sending any more power than it would be to my alpine type s's; which is why i bought the amp in the first place due to them being 75 W RMS.

Now, could I use 2 channels of the amp for my two rear 75 w rms speakers and then bridge the other 2 channels for higher wattage for my front 100 w rms speakers? I need to research more on bridging, but won't this make the impedance 2 ohms for the front speakers? Not sure how I would go about doing this with parallel and series. Any help here would be appreciated .

Lastly, since i alrdy purchased the amp I will be using it assuming it won't harm my type r's, would the sound really be that much worse when only 25 W under the speaker's RMS? Does anybody have experience with underpowering their speakers by 25 W rms?

I know I have many questions, just trying not to screw up my first audio installation and want to learn as much as possible before I start wiring. Thanks guys!

 

It won't hurt your Type-R's but it won't push them to their limits. You're good with 75watts to them.

 

Ok cool. I'm not one to drive around blaring music, but will they still sound decent? Is it worth looking into bridging to give them more power?

 

Not sure you can bridge a channel -- usually bridging is both channels, and you would lose the stereo effect (mono to both channels). 75 should be fine, I wouldn't worry about it.

 

You can try bridging, looks like it will push 125watts to the fronts bridged. I didn't see if that would be 4ohm or not. You do not want to push 2 ohm to those Type-R's.

Try it one way, bridge it and see if you like it better.. Bridging is over power, normal is under powering.

Why not return the amp and get something else?

 

Ok thanks for the replies. I'm probably just going to stick with the amp and see what it sounds like. Down the road I may updgrade the amp, a 100 w rms will be fine on the type s's at 75 rms correct?

 

Im going to start installing in the next week or so, i have another question about RCA wiring. The wiring kit i bought which has good reviews is this http://www.crutchfield.com/p_142PA10/EFX-10-gauge-Amplifier-Wiring-Kit.html . I know it's not the best out there but it fits my budget and seems to have everything i need besides my speaker wiring. I believe it only comes with one set of RCA cables and I am wondering if I need two sets so I can control the fade and what not ( I may be way completely wrong) I believe one for the front channel and one for the rear. Still learning here, but my HU and amp can handle two sets so is it necessary to install two?

 

your gonna need another set of RCA for the rear channel

 

I didn't read to much into this but to make things a bit more clear. You can not mess up speakers by "under powering" them. What a person does to clip the speakers or subs is turning the deck up to where the deck sends out a clipped signal.

Not necessary to have to two sets of RCA's but you will however need a splitter. To control balance and fade you will need a second set.

 

I'll bite this in the butt and give an explanation...There is no such thing as underpowering a speaker/woofer. You can blow a speaker when you drive your amp to clip but not when its set properly.
If we blew speakers by underpowering them, we would have to listen to our music at full blast to keep the power up.
For example, if you see a rating such as 89db/1w that means at 1watt of power to the woofer, you will have 89 decibels of sound. So listening to the radio at "normal" listening levels, you could be using way less then 1 watt of power.
When you drive an amplifer to clip by having the gain set to high, you can destroy a speaker and possibly your amp.

 

^^^^ THIS. But "stories" keep getting propagated due to misunderstanding the true concept. As has been said, underpowering can't blow a speaker. Those that try to turn their amps, either the HU amp or a seperate amp, up too high cause the amp input signals to overdrive the amp output circuits. This causes the amp to clip the output signal, and THIS causes speakers to blow.

Best way to keep this from happening is to set your amps gains using a DMM and a set of test tones. This way you match the amp gains to the HU outputs, and set it too output the max clean power that the amp can.