How much does wattage matter with car speakers?

Question

I've been searching for two 5x7 speakers to get for the back of my car, and what I've found has varied in wattage from 90-220 watts per speaker.... all at around the same price. Does this mean that if I get a two 90 watt speakers they'll be just as loud as two 220 watt speakers? Please help break this down for me please, also rms? thanks

Answer 1

First, you should go only by RMS power values.  Max or peak values are nothing more then marketing tools.

Your question is too vague to answer completely but I will try to give you a general idea...

Power handling numbers will tell you basically how much power the speaker can handle.  The more power a speaker can handle the louder it will be.  However, power handling values are not the only number to look at to determine how loud a speaker is.  One other very important number is the efficiency or senstivity of the speaker.  This is rated in decibels (db).  The higher this number the more efficient a speaker is.  So if two speakers are given the same amount of power then the speaker with the higher efficiency rating will be louder.  

It is totally possible for the 90w speaker you were looking at to be louder then the 220w speaker.  If the efficiency rating was greatly different between the two the 90w speaker could easily be louder.

It is really impossible to say what speaker is going to be the loudest without looking at specific models.  Even then it is not always an exact science.

So bottomline, the higher the power handling does not neccissarily mean the louder the speaker.

One last thing, you should look at more then just numbers when shopping for speakers.  Altough a speaker that has a higher efficiency will be louder that doesn't mean it will be better.  Many of the best sounding speakers will have lower efficiencies.  So numbers are not everything.  I would recommend listening to all the different speakers you are looking at.  Everyone has their own personal opinion on what sounds best and listening to the speakers before you buy them are the only way to tell if you like them.

Good Luck!!!  

Answer 2

If you are going to be using your factory head unit then a pair of pioneer or JVC speakers would be more than enough.  I always look at the quality of the speakers verses what their claimed power handling are.  You can take a pair of Dual 5x7 rated at 200 watts and it will never perform like a pair made by Polk Audio.  If you are going to be using it in a high end system then I would recommend a pair of Memphis Audio MC5.7 they are rated at 50rms/100peak each, and have an effieciency of 93db at 1w 1m, 10oz magnet and 2.125" mounting depth.  http://memphiscaraudio.com I have two sets with in my Ford Ranger and they sound great with the head unit, when I added an amp to supple more power it brought out the full potential of the speakers.  Good luck.