Newb: Do I need an amplifier? Why?

aafflyer

Long time Polk owner, but inside the house stuff (going back to Polk SDA-2B's -- anybody want to buy them as they are just sitting in the garage? -- now a Polk 7.1 solution made up of in-wall speakers and speakers in coffee tables). But I know nothing to little about car audio.

New car. 2009 Mini Cooper. Based on Mini forums recommendations, replaced front door speakers. Went with MM6501 components based on getting killer deal and listening to speakers at local Fry's store. Did self install with woofers in stock lower door speaker location and tweeters in stock upper door location (had to make an adaptor plate out of ABS).

Car has weird head unit that is not going to be replaced -- too much other car electronics and stuff displayed on radio display.

New speakers sound better than stock (junk paper speakers). Didn't worry about replacing 4 ohm with 2.7 ohm as the old stock door speakers (the two of them) were wired in parallel thus offering a 2 ohm load (right?).

Some music is killer, other just there. I'm thinking stock rear speakers are muddling up what I hear -- so rears should be replaced next.

I'm thinking of replacing rear stock speakers speakers with MM691's, but a little worried about the speakers being 2.7 ohm where stocks are 4 ohm. But per Polk site, factory head unit should be ok with 2.7 ohm speakers. Others in Mini forums have used DB691 speakers in rear with no problem.

So many questions ...

First background on me. In mid 50's, so not looking for booming bass. Not looking to blast my music. Not looking to win contests. Not planning to add a sub. Just want nice, clean, pleasant sound in my car.

Mini head unit is supposedly 15 watts RMS x 4 speakers at 4 ohms. Don't know voltage, don't know anything else.

Now the questions:

1) Will MM691's work with my factory unit, or will it "kill it over time" as the unit struggles to drive 2.7 ohm speakers?
2) What will an amp give me beyond more volume than the stock unit, i.e. must I install an amp? Does the music sound "better" with an amp? Would your answer still be better if the amp is getting speaker level input? (see next question).
3) If I install an amp, it's going to have to be one that uses speaker level inputs as tearing apart the dash is not something I am going to do or let anyone else do -- there is a connector right at the driver footwell which has all the four speakers brought to it so I can route the speaker input to an amp from this one location and then route the front speaker wire back from the amp to this one connector and have the stock wire then go to the front speakers and not deal with wires through the door "boot" (good plan or bad plan?). The rear speakers would be driven with new speaker wire direct to the speakers as the amp will go nearby in the back (the boot as Mini calls it).

Because of the nature of the killer deal, if I buy the MM691's (which I am close to just buying them and see what happens), my total investment to replace the stock paper speakers will be about $270.

Any help or advise will be appreciated.

MacLeod

aafflyer wrote: »

1) Will MM691's work with my factory unit, or will it "kill it over time" as the unit struggles to drive 2.7 ohm speakers?

I cant say for sure. Generally the amplifer on any head unit is about worthless and a stock head unit is even more worthless so I would think that it would be ok so long as you dont crank on it too hard.

2) What will an amp give me beyond more volume than the stock unit, i.e. must I install an amp? Does the music sound "better" with an amp? Would your answer still be better if the amp is getting speaker level input? (see next question).

Think of it in terms of horsepower. You dont race and you may not drive fast but wouldnt you rather have a car with 200 horsepower as opposed to one with 120? The reason being is that even tho you dont drive fast, sometimes you need to accelerate fast to merge onto the freeway or pass a slow poke and there may be sometimes when you want to drive a little more spirited than normal. Same with amp power. A good 50 watt amp will be able to reproduce low frequencies easier and more realistic and dynamic parts in the music like a SLAP of a snare drum with more authority which means better SQ. Plus if there are some times when you want to crank it up a bit, the extra power will help. Do you need an amp? No. Do you need more horsepower in your car? No. Is it awful nice to have it there when you want it? Yup.

3) If I install an amp, it's going to have to be one that uses speaker level inputs as tearing apart the dash is not something I am going to do or let anyone else do -- there is a connector right at the driver footwell which has all the four speakers brought to it so I can route the speaker input to an amp from this one location and then route the front speaker wire back from the amp to this one connector and have the stock wire then go to the front speakers and not deal with wires through the door "boot" (good plan or bad plan?). The rear speakers would be driven with new speaker wire direct to the speakers as the amp will go nearby in the back (the boot as Mini calls it).

Most amps these days offer speaker level inputs so that shouldnt be a problem. What the problem will be is noise. Using speaker level inputs means a a higher noise floor (hiss) that could be quite annoying. Another downside is that if you have a newer car your stock head unit could have some heavy EQ'ing going on from its own amplifier so that could mean more noise and more potential to screw up the sound. Buying an aftermarket head unit is the best way. You can look into getting something like a JL Audio Cleansweep or Rockford Fosgate 360.1 which cleans up the stock signal and boosts its output which means a cleaner signal to your amp. They run about $300 or less but worth every penny if youre trying to get the best SQ without swapping out the stock HU.