OK, we just bought a 96 850 GLT Sedan for our son. Drivers side rear speaker has bad vibration. Options include replacing with a Volvo speaker or going after market. Does anyone know of an after market speaker that will fit in the opening that doesn't look like crap? Or is there an after market speaker that will fit inside the housing that the original speaker was in? Next question. The Volvo speakers say they have an 8ohm impedance and most of the ones I see in the stores are 4ohm impedance. What is impedance and will it make a difference in whether or how good an after market speaker would sound? Please help before I pull out what remaining hair that I have.

I would fit the largest speaker possible in the housing that I could. If that means I have to use a dremel, then I would. After market speakers are most common in 4ohm impedence. That means the nominal (average) resistance is 4ohm for the 21-20,000 Hz sound output. Don't worry about this too much. Only problem would be if you went too low and caused the amp/chip to shut down or overheat. Good luck.

By going too low do you mean like a 2 Ohm impedance? If the 4 Ohm speakers wont fry my amp in the head unit, I would prefer to go with them. The frequency response, etc. is probably better than the OEM Volvo speakers.

Eight ohm speakers are most common in home applications. The four ohm units will put more load on the amp. You will get more power from the amplifier, too. You'll need to be careful. I put some Pioneer speakers in the rear doors of my 740, and the OE units are 8ohm, and the Pioneers are 4ohm. I am running these off of the factory amp/headunit, and so far, so good. I have to turn the bass down some, or I get distortion, but that is to be expected. It still sounds just fine, if not better. The front speakers are still the Volvo units, so I don't know what would happen if I replaced them with normal speakers.

Ruling out defective equipment, distortion occurs when your speakers/amp runs out of power (clips). Bass ( lower frequencies) require more power to reproduce, in order for us to hear it we need the speaker cone to move air. This is done easier by using a larger speaker commonly called a Subwoofer. Asking smaller speakers less than 6 1/2"
to reproduce loud accurate bass at higher volumes is too much. Add the amp/sub for the bass. Help your son out with designing the audio system correctly. Decide how much you want to spend and start somewhere. Common items you will need are cdplayer with mp3 or ipod capability,4 nice speakers for mids and highs, subwoofer and amp for the low end. Decide if you want to amp the mids and highs for higher volume levels. If not get a cdplayer that has built in high pass filter to cut out the lower bass frequencies. This will result in higher volume levels for the smaller speakers. I would then add a subwoofer/amp combo to fill in the low end. The equipment is easy to install if you take your time and use common sense.

Well he's not wanting a huge bass sound. He is into classic rock (AC/DC, Lynerd Skynerd, Eric Clapton, Steve Vai, Jimi Hendrix, Led Zepplin, Dire Straits, etc). He likes to hear the guitar parts especially. So whatever I replace with I'm looking for a good clean sound with balance across all parts of the audible range.

I would like to go with 4 Ohm units as there are many more choices and generally better specs (watts, frequency response, etc.) without running the risk of frying the radio. That being said, I can't really afford to replace the whole system at this time, I was going to replace the bad speakers (one in the passenger side rear door) and both of the rear deck speakers.

I am soooooo confused.

Don't be one of those so called spec shoppers. Just because a company says their product is and sounds better is usually not the case. Let yours and your sons ears be the judge. What kind of budget are you working with? Is it an absolute must that you keep the factory radio? BTW they really restrict a nice sounding system, costing more dollars to get similar performance. You will fry speakers far sooner than you will ever blow the amp/IC chip. I can try to point you in the right direction with some product advise, but bare in mind, you get what you pay for.

We've listened to everything we can in our area (Pioneer, Sony, Alpine, JVC, JBL and others that I can't remember the name of). Not just shopping specs, but I've always been of the impression that the wider the range of the frequency response generally the better the sound. So far the Pioneer speaker is the best sound, with the Alpine & Sony tied for second. Fairly restricted on budget so the real high end stuff is probably out of the question. I guess you would say middle of the road. Not looking at any $20 pair of speakers. As of right now, yes we plan on keeping the factory radio. MKC70 I would really appreciate some suggestions. I'm looking at using a 5" x 7" unit that will fit (with modifications most likely) in the existing Volvo grill in the rear deck.

I have Infinity speakers in my Olds, and like them. I would like either Boston Acoustics or MB Quart, but those aren't cheap. They ARE worth it. I would stay away from Pioneer, Sony, JVC. Blaupunkt makes a decent speaker at a reasonable price, too.

The greater the frequency range is just that, a greater range. The human ear can register sounds from 21hz to 21,000hz. What is the range of your ears? This is a max range, with people falling short of each end. When you take a look at the box or fact sheet about the product you will see several numbers. The only numbers or attributes that we want to look at are in this particular order, size(can it physically fit), price(can I afford them), and sound quality(do I like the sound). If you can physically fit 6x9's in the rear deck instead of 5x7's I would. They have approximately 35-40% more cone mass which will result in more sound output. Ford and Chrysler both used 5x7's, w/ Ford still using them today. My personal take on that size is it's crap. Either use a 6 1/2" or larger round speaker, or the 6x9". Remember those speakers will take on some audio characteristics of your car, meaning they will sound a little different once installed.
Take into consideration the sound output will be lower using your factory radio since it produces less wattage than an aftermarket radio or amp. What size front speaker can you install, and where can you put them (dash,door, or both)? If you want to stay mainstream I would stick with the brands you named. They are easy to find and replace without breaking the bank.

Thanks. I just talked to a guy at Best Buy (I know, I know), who actually sounded like he knew what he was talking about. He stated that the 4 Ohm speaker would not harm the head unit, but that if I went to a 2 Ohm speaker then I would probably have problems. I'm going to remove the entire rear speaker housing and take it in and see what will fit. Based on that I plan on buying the largest size that will fit in the housing, that sounds the best and is within our price range.

The way frequency response was described to me was that anything below 20hz or above 20Khz was not within the range of the human ear, but that frequencies above or below this number would capture more of the output and give you a better (cleaner) sound.

Appreciate everyones ideas and help.

That is correct. Taking in your speaker enclosure is an excellent idea. Best Buy around here carries Infinity Reference. They are a good value. Inexpensive, but not cheap. If you can, put a 6.5" speaker in instead of a 6x9. My experience, within the same brand & model lineup has told me that the 6.5" driver will create a cleaner sound. You DO give up some of the bass response by default, but not much. If you choose the right speakers, they'll still do just fine.

As for the 20Hz-20KHz, that is a general guideline to what the ear can hear. I know that my own hearing tops out around 19.7Khz, and bottoms out at 12Hz. There are some weak spots in between, though. If you see a speaker with a high response of let's say 32Khz, that implies that it will create the high frequencies more accurately and crisply.

Is the rear speaker enclosure a factor? Does it even have to be used in the new speaker installation? By having a small speaker in a poor rear enclosure will cause the sound to become muddied. Rear deck speakers can either be top or bottom mounted. This means they can bolt down into the rear deck,or up from the bottom. If this is the case then put the largest speaker you can fit.

I wouldn't, other than the way the speaker well is designed in the 850 is a rectangle that is a depression in the rear deck where the speaker enclosure sits. I've seen on this or another forum where someone installed a 6' x 9" oval speaker in the bottom half of the stock enclosure. It hung out over the ends and didn't cover the opening completely. That was just an installation that didn't look clean to me. I prefer a cleaner looking installation. Since neither me nor my son is looking for a monster setup with booming base. . . a smaller speaker that still sounds good but gives a clean looking installation is preferable. I was just wanting to make sure that if I changed the impedance of the speakers that I wouldn't fry the head unit.

Now I'm planning on replacing all the speakers, except in the dash. I measured the door speakers but I can't tell for sure if the fronts are 5" or 5.25" and the rear doors are somewhere between 5.50" and 6". Does anyone know the sizes I should replace with?