Diagnostics
I bought my 1993 BMW 850 Ci back in March 2000 and one of the things that I immediately noticed was the extremely low quality of the sound reproduced by the stock sound system. From what I have read, these cars were delivered with either a fairly standard 10 speaker system or with a HIFI 14 speaker system(2 speakers reserved for the phone). As my car came with the 10 speaker system, this text only describes one of many examples of how that system can be upgraded.
I am a person who enjoys music a lot and as I am a Latino to start with, samba and other very rhythmical flavors of music is what I enjoy pumping in my car. I am not a volume freak, but I do care a lot about the different details of the music being reproduced as accurately as possible. The problem I had with the original sound of the car was simply that the overall sound picture contained too much bass. Even when I brought the bass to its lowest levels, the high frequencies were simply muffled inside a humming and abstract low frequency sound soup which made me wonder if my ears were clean or not.
My second problem was that the bass also tended to get distorted at fairly low volume. Instead of having well defined bass thumps in my music, the kick panel speakers could simply not reproduce the bass power that was being sent to them. Instead the bass power disappeared and was replaced by a vibrating, muffled bass sound which tended to drown the details of the music even further. I hated it!
The third problem was the very bad quality of the tweeters in the door panels. When listening to music that did not contain too much bass, I would notice very rapidly that the high frequencies were extremely squeaky and intermixed. The result was more or less what you get when you speak with somebody over the phone and that person almost shouts at you. Instinctively, you pull the phone from your ear and close your eyes as the sound simply cuts within you.
Doing something about it
Imagine my frustration. I had the most wonderful car I could ever wish for, but inside it resided the worst sound system that I had ever allowed to violate my ears! I took the car to a very well known auto audio shop and had one of their guys listen to what I thought I heard and he agreed very much with what I was telling him. My original thought was to have the whole sound system replaced, but he told me very honestly that such a problem should be addressed step by step starting with the speakers. His idea was simply to change a pair of speakers at a time, to make sure that the solution we were bringing forward was moving towards the wishes I had for the final result. It would result in some extra labor costs, but it would at the end make me have a system that I really wanted to have. His proposal was to start with the kick panel speakers, followed by the door speakers, followed by the rear speakers. Three different areas to work with took us three days to have it all done as I was working very hard at that time and just couldn't get off work a whole day to spend it with this guy and the car. But the good thing was that every night when something was replaced, I had the chance to take the car out and listen for improvements and simply return the car back next morning with my comments.
Replacing the kick panel speakers
During the first day we concentrated on replacing the kick panel speakers. The stock speakers are 4" speakers held into place by a black plastic frame screwed into place by three metal screws. Section 65 12 000 in the repair manual describes how the kick panels are removed to access the kick panel speakers. This description is confusing and not well depicted and described. What you FIRST have to do is to remove the plastic panel above the pedals. This panel is held into place by four, black plastic screws (two in the front and two in the back just between the pedals). You need to remove this panel to be able to get out the kick panel easier, but finally to be able to unscrew the third screw that holds the speaker frame in place. The kick panels are held into place by two smaller, black plastic screws (you need good illumination!) and on the driver's side by an additional metal screw holding the hood release lever in place.
Once you have removed these two panels, you will see the rather small speaker held into position by a black plastic frame. We saw directly that the frame was going to be able to hold a larger speaker in place and we decided to upgrade the stock 4" garbage speakers to something better. Knowing that one of the major problems in the car was that I felt I had too much "dirty" bass, we decided to install a 5.25" Infinity Referens 552i speaker, which is a coaxial speaker that contains a centered tweeter that can be directed in a range of 350 degrees. The cost for a pair of these speakers including frequency division filter is about $100.
Step one is to make a copy of the plastic frame and copy its shape and the holes for the three metal screws. Step two is to make a hole in the frame to fit the larger speaker. Step three is to install the new speaker and make sure to direct the tweeter upwards towards the driver/passenger, as the high frequencies are very direction dependent.
Comment on the result
When driving the car that night with this simple upgrade, the change was enormous! The previous bass which was distorted at low volume, was now well defined and clear all the way almost to top volume! A big part of the "dirty" bass was gone, and the tweeter added a much better clarity for high frequencies that were now clearly audible from the front of the car and not only from the door tweeters. Purists will probably argue that it is useless to add tweeters so low and far away from the ear, but in my case this actually did help!
Replacing the door tweeters
My problem with the door tweeters was simply that the sound was way too squeaky. Also, a clear problem is that these tweeters are placed very low and aimed at your stomach, unless you are VERY short and have your head where I have my stomach. My 1998 BMW 535i has a much more modern sound system and both on the driver and passenger sides you have two tweeters directed directly towards the listeners. One is on the door just under the window and the other at the base of the A-pillar where the side mirrors are located.
To be able to access the door tweeters you need to remove the door trim panels. The description for how to do this is in section 51 41 000 in the repair manual. I was not present when the changes were made to the tweeters, but I learned they had no problems removing the panels and putting them back on. The original tweeters were here replaced with 1" Visaton CT 25 tweeters. A pair of these will cost you about $85.
The new tweeters were installed so that they were tilted slightly upwards, so that they were directed towards my head from behind the protective grill in the trim panel. This by itself made a tremendous difference, which amplified the stereophonic effect in the car several times over.
Comment on the result
Driving the car that night produced a grin that I had problems getting rid of. The squeaky nature of the stock tweeters was gone. The direction was perfectly calibrated and in combination with the front tweeters from the kick panels the result was a pure joy. The only problem I now had was that the perfection that was now taking place in the front of the car was more than ever clearly divided from the still "dirty" bass coming from the rear speakers. This was the subject for the third and final day.
Replacing rear speakers
The plastic grills cover a small cluster of three different speakers. One of the speakers is a 4" speaker, the second is a 3" speaker and the third is a 1" tweeter that (believe it or not) is correctly aimed forward towards the driver/passenger. The only remaining problem we had in the whole sound picture was that I felt the bass coming from the back of the car was still rather distorted or muffled. The proposal from the audio guy was to just replace the 4" speakers and leave the rest alone. The 4" speakers were therefore replaced by 4" Pioneer TS-G1045, which cost me about $50 a couple.
Section 65 12 020 describes too shortly how to access the speakers in the back and the actual pain getting into the back of the car to access them. [As every E31 owner knows, the rear seat was never meant for human habitation -- far less providing adequate room for a burly stereo installer. PMB] You need to move the front seats all the way forward and tilt them forward. Be VERY careful with the plastic protective grills when removing them from the hat rack (rear shelf). Use a putty knife to first release the tabs from the front, short side. Then gently move the whole grill outwards (from the center of the hat rack) to avoid breaking the side plastic tabs. This is a pain and you have VERY little maneuvering space, so take your time and be patient.
Comment on the result
The audio guy seemed to know what he was talking about and once we examined the 4" speakers they were cracked. Replacing them caused the whole sound system to come into a perfect balance and I really tell you it was worth every effort we put down into making these changes.
Final word
The Swedes have a nice saying that says "Taste is like an ass...divided!". This is so very true! What one person can come to love, the next can hate.
I want to you remind you all that I in no way claim to be an expert on audio brands or sound system. I have with this text only described upgrades I made to my car to achieve a sound picture that I was looking for. Don't select my speakers just because I did so and don't make my changes just because I did them. You need to analyze your problem in several steps and here at the end I am simply trying to give some good advice to how you can reach YOUR goal on improving YOUR system.
1. Make sure to first try to identify exactly what it is you don't like about how your car audio system sounds. Put in several types of music into your CD-changer and listen to your music in different volumes and write down the defects you think you notice. Use a wide variety of music to understand better the range of the problem you want to remove.
2. If you know what is "wrong" with you system it is also because you probably know what you want. Visit several auto audio shops, but make sure to only visit reputable ones with those small isolated rooms where they allow you to bring your own CDs and select different speakers from a matrix on the wall. Don't get fixed up with a brand to start with. Identify the set of speakers you think reproduce your music in the way you want and THEN look at the brand to make sure those are speakers that at least will last. Taste here is VERY individual, so my selection is what I liked best. Your selection might be something totally different.
3. Try to get the shop to make the replacements for you, unless you find some joy in doing it yourself. These guys know what they are doing and you will avoid messing up things.
4. Try to make the upgrade in different steps if possible. This costs you more in labor, but it will guarantee you a better final result. If you have the time, make a deeper analysis of the sound for each pair of speakers your have replaced. Write down the improvements, write down your new ideas and take your time.
Final cost
The speakers I bought ended up costing me $235, which for me is an acceptable number. For labor I had to add an additional $250, but this price was lowered as the guy that helped me out claimed that it had been a pure joy for him to be allowed to have such a nice car in his shop for three days. If the shop is a good one, and the guy who does the work is committed, he will take your comments as a challenge and the working process will be enjoyable.
Good luck!
Fedde Engler
