I've known their site to not recommend items that actually have fit. Maybe they err on the conservative side, or try to match the OEM speakers dimensions, IDN.

Your choice, but you might buy a single pair of either of the full size models and place fit one in all the positions before ordering the 2nd set.

Or for the Polks, maybe you can 'borrow' one from your boat to place fit/test.

The full sized models should in theory offer a better low frequency response (woofer excursion) than the shallower models...

I just did this project on my daughters 2000 CRV-EX during the holidays. I put in a new head unit and four new Polk DB650's. I bought everything from Crutchfield and am very happy with the install kit which includes the wire harness and mounting kit / faceplate. The instructions Crutchfiel gives you for the head unit install are good, I followed them and didn't have an issue. I know that their website lists the regular (not shallow mount)DB650's as not fitting but they do. I used the included adapter rings to get screw holes to match up and yes, I cut the plugs off the wire and put on spade terminals to slip on the new speakers.
I got her a sony head unit that has full controls for the iPod as well as charges it, USB input on the face, and bluetooth hands free for the phone. The whole setup sounds way better than stock and she's happy about being able to control the iPod, which is what she listens to 99% of the time.

One nice thing about Crutchfield is that they also provide disassembly instructions for removing the dash and door panels. Sure you pay retail, but they offer a value-added service, so it warrants the extra money you pay for their information in my view.

There is one confusing issue with power, especially with car stereos. There is an old bait-and-switch marketing technique (although I think it has more to do with dis-honesty than markteting), that some manufacturers rate their stereos at peak or peak-to-peak.

This used to be the norm in the '70s with some cheap department store brand stereos, where they would advertise a 100 Watt stereo, but it was actually only maybe a true 10 Watt system.

Fortunately, the FTC got involved and required stereo companies to either not advertise their power output, or if advertised, only as RMS, not peak, inverse Peak-toPeak, IPP, whoodo, voodoo, or any other fuzzy terminology.

But for some reason car-stereo companies were exempted from this ruling - most likely because there was not much of a car-stereo aftermarket in those days.

But a couple of years ago, some car-stereo manufacturers decided to clean up the system, and came out with a standard, called CEA-2006, that specified RMS ratings only. However, even then, RMS ratings are somewhat meaningless without the accompanying THD (Total Harmonic Distortion) rating, as the two are related.

Let me explain:

One typical distortion rating is 0.1% THD, as that is about the maximum THD your system can have before you will hear it.

As kenhdog suggested, as you overdrive a stereo system (overdrive as in trying to obtain more power than you should), the system starts to clip. The clipping is actually flat spots in the signal, and is actually caused when the signal is so large that the signal exceeds the input voltage of the amplifier. Well, this is getting technical, so we'll just say that distortion is bad. While there is no such thing as no distortion in an amplifier, it is typically so low that is does no harm, nor is audible.

However, as you begin to increase the signal beyond limits, those flat spots caused by clipping begin to raise the distortion level to the point that first it will become audible, then it will start destroying components.

So an amplifier rated at 100Watts RMS at a THD of 0.1% could be overdriven to put out 120Watts RMS, but then the THD will raise if the unit goes into clipping, so the THD might then be say 3%. Without a THD requirement, one manufacturer could rate their system at 100W RMS and another at 120W RMS.

Obviously, most folks would chose the 120W system. However, if the 100W system was at 0.1% THD and the 120W system was at 3% THD, the comparison is not fair, and in fact, it could be possible that if the 120W system were rated at 0.1$ THD, it might only output 90Watts.

So even with CEA-2006, you must look at both the THD and RMS figures to accurately compare units.

By the way, our ears respond to sound logarithmically, and not in a linear fashion, so it takes a 3dB change in power to sense any difference in loudness. Three dB is a doubling of power, so in reality, you will not even hear any difference between a 100W and 120W amp. Most of us would need to compare 100W and 200W signals to even hear a difference in loudness.

But how much power do you really need?

You might be surprised that in an enclosed environment like an automobile, 1Watt is louder than you might think. For most of us, a 15Watt to 25Watt system in an enclosed area is sufficient.

However, bass frequencies take more power than high frequencies, simply due to more mass in a woofer needs to be moved, and more mass requires more power. If you have subwoofers, your gonna need more power.

But my take is that most of the time, if you have a moderate quality head unit in the 25Watt range, any moderate quality loudspeaker will suffice, without regard to the power rating.

There is a lot of confusion about loudspeaker power ratings. The rating is done in a controlled environment, where a single-frequency sinusoidal wave that does not vary in amplitude is applied over a long period of time (relatively long vs. the actual signal), and the maximum power rating of the speaker is taken from this.

Unfortunately, this has nothing to do with real life. In the dynamic range of music, the softest softs vs. the loudest louds, especially since the days of digital content on CDs, can approach 90dB. This means the loudest signal can be as much as 1 billion times greater than the softest. Of course, this is the best-case capability of the system itself, not necessarily the music content.

But what this does mean is that for 99% of the time, the demands on the amplifier will be much lower, and any peak musical information, such as a drum beat, will be the only thing that might require the higher power output of the amplifier.

What I am trying to say is that regardless of the power rating of the loudspeakers, the chances are that 99% of the time, a relatively low amount of power is being supplied from the amplifier, but only in short bursts of loudness does the amplifier have to output high power.

Most loudspeakers can handle this high output for short periods of time, even if it means it exceeds it's power rating, as the musical transient is over before the speaker coil has a chance to overheat and melt.

But of course, if you are listening to Ozzy with no dynamic range at the highest levels, expect things to be overdriven and melt. But for the most of us, our musical selections are such, and our hearing is not burned out, so that we will not need to crank the volume so much for this to happen.

One other point I'd like to elaborate on is something else that kenhdog mentioned; that you can burn up a set of speakers faster with a underpowered amp than an overpowered amp.

Of course again, this is relative, depending on the volume level you are listening to. But what happens is that a lower powered amplifier will begin to clip sooner than a higher powered amp. If you begin to hear distortion out of the speakers due to overdriving the amp, you are at the point where speaker damage can be done.

If you were to look at the waveform with an oscilloscope, you would see flat spots at the top and the bottom of the waveform, which is where the term "clipping" comes from, as the waveform peaks are clipped off. What causes this is the waveform is a voltage swing, and the amplifier is trying to amplify so much that it is exceeding the voltage limit of the power amplifier; thus the clipping actually ends up being DC voltage supplied to the speaker.

The more severe the clipping, the wider flat spot you will see, and the longer time DC is being applied to the speaker's voice coil. DC is bad for a speaker. If you hooked a speaker up to a battery for instance, it would soon overheat and burn out.

This exact same thing is happening to the loudspeaker when you severely overdrive it. Therefore, if you had a more powerful amplifier, the clipping would be less, and since the musical peaks are short transients, the loudspeaker's voice coil can handle those easier than DC clipping, so there will be less chance of burning out the speaker.

But of course, if you play the music loud enough, you'll even burn out that speaker.

Al's first law of loudspeakers; A speaker cannot be designed to prevent it from being destroyed by some fool that cranks the volume up loud enough.

But I digress. Any moderate quality loudspeakers, such as my favorite Polk DB series will give you satisfactory performance with any moderate quality aftermarket head unit; especially one rated under CES-2006. To me, the CES-2006 rating means the manufacturer is one of moderate to high quality, and perhaps is the bellweather in separating the junk from the quality stuff.

Sorry for the long reply, its been awhile, the raconteur that I am.

keith - thanks for the tips on the polks and suggestion to try the one from the boat. should have thought of that one myself.

al - good to know i don't need a bagillion watts of power.

btw, here's the head unit i'm thinking about. interesting philosophy....no need for cd's if i'm playing the ipod. and why not plug the ipod into something that charges it without having a tangle of wires. while we're at it, let's charge the ipod AND make it available close to hand to see what's playing. and here's the part i really like.....let's make it cost $99. it sure ain't pretty, but it's functional and cheap and i'm gonna give it a try. i don;t have an iphone, but it docks in the thing as well and charges. you can also answer it while it's docked. pretty cool.

http://www.engadget.com/2009/11/18/dual-electronics-xml8110-in-dash-iphone-dock-announced/

I have a Dual in my car and it works fine!

the same model i linked or a different one?

I have this one: http://www.dualav.com/mobileaudio/xhd6430.php

Use an iPod cable to run and charge my iPhone through it.

HD radio is excellent on stations that provide it! Its the real reason I bought it ... I wanted to try HD radio and it was cheap (~$90 at walmart).

It has a shocking amount of configuration abilities. I was impressed. Way better than my previous Sony one was. If you get it, be sure to turn the Loud function on. It really made my audio sound pretty dang good.

I bought a new stereo system last summer that included an external amplifier with two subwoofers, an iPod interface, a hard drive to dump CDs to, and a Compact Flash card reader I can load MP3s on. It cost $37,000, but included a free car.

wow. too bad they have that free car give away now. actually, despite being a 10 year old car, the cr-v only has 70k miles and runs and looks great. tough to justify a new car.

Bruce, if you decide on the Polks, try these links:

Polk DB651

Polk DB651S

I am kind of surprised they are still at this price, but I guess it is your lucky day.

BTW, I have bought lots of equipment from Crutchfield, and many times, made it fit even if Crutchfield did not say it would. Does Al give awards for cutting into your car???

Nope. Just boats.

Well of course this thread got me to thinking about the Infinity's and my above comment, so I just ordered a set. The urge became urgent when I found out the 5.25 versions I need/want are discontinued... I think I found a slightly used (1 month) set on ebay and pulled the trigger.

well, here's a quick update.

i ordered the infinity's (slim model) before checking back and seeing waywego's post. i can't believe the price on the polk's is the same as the infinity's. oh, well.

i installed the infinity's which were easy since they didn't require any modifications and the pigtail connectors were a snap (literally). i noticed an immediate improvement over the factory speakers.

still not great sound, but the new head unit is back ordered so i'm still using the old one. in a few weeks i'll install the new one and should get great sound and easy ipod functionality.

Which head did you order?

this one.....

http://www.engadget.com/2009/11/18/dual-electronics-xml8110-in-dash-iphone-dock-announced/