Speaker/Amp Question and Help

Systems

My basic question is what size amp should I get in relation to my speaker rating? Do I look at the speaker RMS or peak value to determine the size amp I need? I thought I was suppose to match my amp to my rms value on my speakers but I read an article here at Polk and it said something different. Could someone please clear this up for me?

Second, I have the following Polk speakers in my car:
MMC690 6x9's 100W(rms) 200(peak)
MM6 comp. 150W(rms) 250W(peak)

I am going to buy 2 amps and I would like to know what amp size I should get to make sure that I dont over power my speakers and blow them. I am also a little confused about the MM6's they say the recomended amplifier power is 25 - 150W am I pushing it to much or pushing the tweeters to much at 150W?

Thanks in advance for everyones help.

Jstas

For the MMC690's you should get an amp with an RMS value no lower than 60 watts per channel. You can push the RMS value up to maybe 110-120 watts per channel if you feel like gambling otherwise, don't go past 100 watts RMS per channel.

For the MM6's, I wouldn't go any lower than 85 watts RMS because of the heavier structure of the MM6's. You can probably push the MM6's to 175-200 watts per channel fairly safely. Others have done it here but really, unless you want to go deaf, 150 watts peak RMS value is more than enough power.

As far as what power ratings to go by, you can safely ignore the peak values on speakers. They will mean very little in the grand scheme of things. Don't buy speakers and amps for thier peak value, always use RMS as your main buying spec when considering power levels.

When buying amps, you can't ignore peak values because even though they too are fairly unimportant, they do have more value than the peak rating in speakers. The peak power ratings in comparison to the RMS values for the same amp can give you a good idea of how much over-heard the amp has and how well it will perform under heavy loads (high volume). However, the RMS values should be your main power spec consideration when buying amplifiers also. It is more important to match RMS values than it is to match peak values.

Remember too that too much clean power is much better than no enough dirty power. So don't buy an underpowered cheap amp for expensive, high power speakers.

Systems

Thanks for the info. So would the following be good or could I do better?
Amp for the 6x9's Rockford Fosgate Power 351s 90Wx2RMS ?
Amp for the MM6 Rockford Fosgate Power 451s 115Wx2RMS ?

But how do I determine the Peak value of those amps, they dont seem to be listed anywhere? I assume that it would be good to know the peak value on the amps so I dont have a peak larger than the peak on my speakers, correct?

Jstas

Yes, you are correct but it isn't as important as you are making it out to be. Don't worry aboutthe peak power, both of those amps should work out just fine for you. You may be able to do better but most likely not with RF. Look around, there are many sites out there with audio equipment at good prices. Some company is bound to have something that you would like better if the RF stuff isn't to your liking.

You may want to see if you can't up the power for the MM6's to 125 watts or more. I know they are power hungry and respond well to increases in power.

Some other brands to check out in that same price range
Alpine
Hifonics
Kenwood
Polk Audio

I'm sure someone else will chime in here too.

Systems

My only other comparision is my sony amps that got shorted out with water the other day from a leak in my trunk. I could go with the next RF which are 140W x2RMS.

The other question is would it have been better to put a pair of 6.5 in the back instead of the 6x9's?

Jstas

Well, that is a good thing that the Sony amps are no longer working. Working or not, they make great doorstops!

As far as 6x9 vs. 6.5 round, it's up to you. Both will perform equally well with a slight edge to the round speakers for sound quality. However, you have to consider ease of mounting, price and availability. Not only that but it will change your choice of amps too. But if 6x9's fit the hole, stick with them for now and upgrade later if you like or just leave it. They aren't a bad choice at all and if you like them, whats the point in changing? Besides, you are barely going to hear the rear speakers anyway so it won't make much of a difference.

sntnsupermen131

try the 551S, i think it would do you better, i have the older version of that amp running my mm6's and it works out great
as far as 6.5s vs 6x9s
if youre going to get a sub(s), then id go with a nice 6.5 coaxial, or if you want to spend a lot, go with components
if youre not planning on getting subs, then id go with the 6x9s because youll get more bass out of them than 6.5s
and with polk's momo line, you can safely go over their RMS rating about 25%...i have 200-225 on my mm6's(my RF amp is underated)
and i had about 615 watts on my mm12s when i had my old bd1000
so you can go to 200 watts each for the mm6s and about 125 for the 6x9s with no problems
-Cody