I am currently in the build up stage of my audio project, and I have decided which speakers to run: Infinity Perfect 6.1 Components. The ratings for these speakers are: 100W RMS and Peak 400W.

When searching for an amp, do I look at RMS Power Output or Power at 2 Ohms? For example, here are the ratings for the Alpine MRP-F450:

RMS Power Output: 70x4
Power @ 2 Ohms: 100x4

Paired with the Infinity Perfects 100W RMS, will this amp be sufficient? I know that you want to have the amp and the speakers hitting at the same RMS, but 70W is obviously short of the 100W the speakers require. Or do I use the 2 Ohm measurement, in which case the amp is spot on?


My last concern is in regards to the amount of power the amp is pushing. If I step up to the MRP F550, here are the specs:

RMS Power Output: 90x4
Power @ 2 Ohms: 125x4

In this case the amp overpowers the speaker's 100W rating. Would this be too much? Both amps cost the same, which would I be better of going with?

I intend on just replacing the front speakers and shutting down the rears. I would think a 2 channel amp would be better than a 4, but I want to have those extra channels for future use if I decide to run rears, a sub or get a new car.

 

The Infinity Perfects are 4 ohm speakers, so you look at the 4 ohm rating of the amp. Ideally you will want an amp rated at 100 rms watts per channel to push the components, however, in the real world 70 watts rms and 100 watts rms would be near impossible to discern which is louder. If you like to listen at really high volume levels then you may want to look for an amp rated more around 125 rms watts per channel so you have a little overhead. This will allow you to stay far enough away from clipping the amp while running the snot out of the components at full volume levels.

On a side note, unless you are going to bridge the 2 rear channels to power a sub, just get a 2 channel amp and save some money. If you NEED to have rears later, just power them off the headunit.

 

Perfect's sound awesome with a nice chunk of power.

Try getting a 4-channel amp and bi-amping it.

 

Thanks for the reply, you cleared up most of my issues

I haven't decided about how I would run my sub... I have a mono sub amp that I got from a friend but I am not sure what the output is, but regardless, I would only get an 8" or 10" for behind the driver seat. I want to have everything hidden, so running the fronts and sub off of one 4-channel amp would be preferential. As for the rears, I could run them off the HU. I just got the Alpine 9887 for X-mas; not sure what speakers I could run off that, but they would be filler anyways.

So neither of the Alpine amps would be sufficient enough for these components. I would either need to step up to their more expensive PDX line or find another brand altogether. I just looked, and most 4 channel amps hit a price wall at 90Wx4. After that stuff starts getting pricey, which might steer me towards going with the 2 channel option. Any suggestions?

 

Bi-Amp?

 

What's your budget? And again, both amps you listed would indeed be sufficient. If tuned properly you will cause NO damage to the speakers and it will sound just as loud as if you were running 100 rms watts.

 

This is the amp I have powering my components. It's full-range class D (like the Alpine PDX amps), so it's very efficient and I am very pleased with the SQ of this amp. It also has a somewhat small footprint.

http://www.eclipse-web.com/amp/xa2000.html

http://www.woofersetc.com/index.cfm?...roduct_ID=4618

 

I want to stay around $200-$300 on the amp. Just looking online now the MRP-F550 can be had at ~$220 while the PDX lists at ~$300. Now, there is a 2-Channel Blaupunkt (Blaupunkt PCA2120) for $100 which would be more than sufficient (120Wx2). So I have a $100, $220 and $300 choice!

 

Run one channel to each speaker in the component. So one channel to one tweeter, one channel to the woofer, and another channel to the other tweeter, and another channel to the other woofer.

It's difficult, but the payoff in sound and clarity is excellent, and well worth it.

 

Another brand that doesn't get much notice is Clarion. I have a couple of their amps, and they are great, and quite reasonably priced as well.

http://www.clarion.com/us/en/product...294762695.html

You could bi-amp that one, and with Perfect's, it would be a beast.

 

Just a note to the OP, this method requires the use of a separate active crossover (NOT the passive crossover that comes with the component set). Some high end headunits have a built in 3way crossover for this task, otherwise you will need to purchase an active crossover.

 

Thanks for the explanation and suggestion. I wish I could check out someone's ride with these different options installed! I am still not certain how I want to go. I really want to have the 4 channels for future use, but don't necessarily need them.

I just got home and checked out the 2 amps that a friend of mine gave me from his old install. 1 is a JL 250/1 Mono Sub amp, so that looks like my sub amp option is made up The other is a Power Logic Component 45x2, which I may keep around just to have.