Upgrading the E34 Stereo Tutorial

[Mark185]

Mark, here is a question for you: when you are done with your car and I am done with mine, can we meet somewhere in the middle of the country and compare SQ?

I am glad to see we are both on the same page. Active is far superior, driver distance (and phase angle!) affects both slope and crossover points, but a properly designed (for the car, not a computer screen) crossover can still do just fine, especially considering cost.

I would like you to install one of my crossovers when they are done. Not in your car, obviously, but do you think you can find a local who would want to go that route?

I so want a "review" from you (a couple other guys are on this list too, worry not)!

Luke

I would love to take a road trip and meet somewhere in the middle. Not sure if it can be done when I take into account wife, kids, and my dwindling amount of vacation time but I am more than willing to explore this idea.

Just to bounce this idea around, what are you doing to design the crossover for the car environment? I intend to measure the frequency response of the raw drivers without crossover filters while they are mounted in the car. I will take somewhere between 4-10 measurements at different locations and average the curves. The average sound response is the curve I will use to set crossover points. I have never been a big fan of tuning the sound for only the driver's seat. It might yield better imaging but in a daily driver, I like going for a better average response across both seats. I am strongly favoring the 2" Peerless speaker as the best replacement for the stock midrange. It will be easy to fit and is clearly an upgrade from the OEM one. The trick will be figuring out the best crossover point. The Lanzar limits me to 240 Hz at 12 dB per octave. It would be better to cross at a higher frequency. Still thinking about this one...

If someone in NJ wants to try one of your crossovers, I would be willing to help install and review it. If you want to loan me one, I could probably install in one of my cars to check it out. I have 2 tourings. One is my daily driver and the target of this thread. The other is a project that I am taking my time with. It won't be on the road for a long time but could also be a test bed.

[Matt Z]

Not to interrupt but, wouldn't your frequency response measurements be different then what you would get in a sedan because of the different interior volume/shape? I know that differnet rooms have different acoustical properties, so wouldnt that be the same in a car? Or would it not create a noticable differance?

[Mark185]

Not to interrupt but, wouldn't your frequency response measurements be different then what you would get in a sedan because of the different interior volume/shape? I know that differnet rooms have different acoustical properties, so wouldnt that be the same in a car? Or would it not create a noticable differance?

The bass response would probably be different with a subwoofer because interior volume is different, but I doubt the kick panel speakers go low enough to make much difference. The front soundstage should be the same for sedan and touring models.

[K Fox]

The bass response would probably be different with a subwoofer because interior volume is different, but I doubt the kick panel speakers go low enough to make much difference. The front soundstage should be the same for sedan and touring models.

^^ This. The phenomenon is called 'cabin gain', and the kick panel speakers don't really go low enough effectively to use it (shouldn't really go that low at all, that's what a sub is for).

Fox

[Matt Z]

oh ok, you learn something new every day. haha Im just starting to get into audio so that is why i ask al the questions.

[Stereoinstaller1]

Hmmm.

Started doing a bit of more critical listening to some test tones. (full 20 octave sine sweeps if it matters, plus specific sweeps from 50 to 500hz)

Currently, I am using JVC deck power to the stock 6db/oct passive crossovers (full 4 channel input, no shared input grounds) and all stock 1989 drivers. My subwoofer is one of my 12" vented boxes, with all of the bass output sealed into the cabin. It runs from 80Hz or so at 12db/oct, while my midbass drivers run from 100Hz or so (again, 12db/oct) on up.

There is a clearly a HUGE gap between the top of the midbass and the bottom of the midrange. It makes the sound quite "recessed", less "in your face", which is a typical trait of European home speakers (of that era, at least) as well, that very "laid back" lower midrange...so I suspect that part of the phenomenon is actually cultural preference!

In my mind, that gap is also needed due to the phase angle of the driver (for the audio newbies, a bare "speaker" is called a "driver") location. Figure it like this, if the plane of reference is the midrange, the midbass is 90 degrees off axis just to start with, then twisted to radiate horizontally (compared to the near vertical dispersion of the top of the dash) too!

Again, for the newbs (please don't take me for condescending, I LOVE sharing this stuff, but I tend to get too technical) lets talk about ideal driver placement in terms of wave propagation for just a second.

In an ideal world (say, your living room or a test chamber) you would have all speakers on the same plane, typically with a horizontal dispersion. Just like your normal 2 channel home speakers, right?

If you wired 2 drivers "180 degrees" out of phase (like connect 1 speaker backwards) you would have cancellation of virtually all low frequencies. In essence, 1 speakers wave "eats" the other speakers output.

This phenomenon is EXACTLY the same as turning 1 of your theoretical speakers backwards, but having the wiring correct: it is simply the speakers wave firing backwards, but only from 1 speaker.

The fact is that anytime 2 speakers in the same space are not on the same plane, they will fight each other no matter what. No amount of electronic trickery (EQ, DSP, time alignment, whatever) will fix this properly...it is simply a mechanical issue.

This phenomenon is easy to demonstrate by moving the balance side to side: out of phase will show more bass from either speaker than with the balance centered.

So, the common misconception is that speakers only have "in phase" and "out of phase", or "180 degrees". The reality is that the waveform can be up to 359 degree out of phase.

This is critical to understand, and simply cannot be shown on a computer screen.

So, think about this: the low frequencies in your car come from the rear deck, where we have 2 little drivers in phase with each other, then (this is where it gets ugly!) we have 2 more low frequency drivers in the kick panels that are roughly 90 degrees out of phase from the rears...not to mention the phase issues from the upper end of the response spectrum of the kickpanel speakers to the dash speaker...no wonder there are huge "gaps" in the response, that is most certainly the easiest way to eliminate the fighting, just acoustically separate them!

It is a car, so we get to compromise right?

My muscles are burning from the typing and I must get back to work...but I hope my drivel being posted helps at least someone.

Luke

[84318i]

"This is going to happen any time you have a large distance separating speakers with respect to the size of the wavelength of the frequencies in the crossover filter range. For example, the wavelength of sound between 300 Hz and 1000 Hz varies from 3.75 feet at the low end to ~ 1 foot at 1000 Hz. If you are crossing over from a kick panel woofer to a dash mounted midrange in this frequency range, it will be impossible to get a smooth frequency response between 300-1000 Hz because the separation distance between the drivers is greater than or equal to the wavelength of sound in this range. It has to do with the time of arrival of the sound waves from each driver and how the sound waves combine in the crossover region. "


And this is why sometimes simple is better, as in a really good two way with tweeter and mid very close to each other IMHO

But I do understand you guys are trying to improve on the stock speaker locations, just seems like a lot of work for that.

[Mark185]

"This is going to happen any time you have a large distance separating speakers with respect to the size of the wavelength of the frequencies in the crossover filter range. For example, the wavelength of sound between 300 Hz and 1000 Hz varies from 3.75 feet at the low end to ~ 1 foot at 1000 Hz. If you are crossing over from a kick panel woofer to a dash mounted midrange in this frequency range, it will be impossible to get a smooth frequency response between 300-1000 Hz because the separation distance between the drivers is greater than or equal to the wavelength of sound in this range. It has to do with the time of arrival of the sound waves from each driver and how the sound waves combine in the crossover region. "


And this is why sometimes simple is better, as in a really good two way with tweeter and mid very close to each other IMHO

But I do understand you guys are trying to improve on the stock speaker locations, just seems like a lot of work for that.

Absolutely true. A high quality two way with tweeter and mid close together will sound better. Hard to do in an E34. I tried this in my kick panels but was impossible to get the tweeter and mid aimed towards my ears without giving up the dead pedal on the driver's side. Mine is a 5 speed conversion and I won't give up the dead pedal for better sound. I have seen this approach work very well in front drive cars with automatic transmission. Getting rid of the clutch pedal and eliminating the driveshaft tunnel makes this much easier to get good results.

It is a lot of work to try to get the best out of the stock speaker locations. Simple is better and my favorite install approach right now is to use a high quality 3" full range driver in a pod on the A Pillar and cross it over as low as possible to a door or kick panel mounted mid-woofer. The 3" driver is aimed to focus direct sound arrival at the listening position and reduce the number of reflections off the windows and dash. This works in part because the 3" driver begins to 'beam' at higher frequencies because its off axis frequency response drops off. It does not eliminate reflected sound waves but reduces them compared to a two way with a tweeter. This also requires the use of a decent equalizer to tweak the full range driver's response. This is a two way but not in the conventional sense. I like this approach because it gets the crossover filter mostly out of the critical range where our ears are most sensitive (300-3000 Hz). I say mostly because the low end crossover still has to be around 300 Hz. I am doing an install like this in my wife's Outlander and will probably use a Zapco DSP6 with some old school Soundstream D-100 and D-200 amps. I tend to buy high quality used equipment from places like diymobileaudio.com classifieds. I couldn't afford this stuff when new and think it is a better value than the new amps and processors on the market in my price range. I also don't have a good mobile audio installer in my local area worth supporting with my business.

This is way out of the scope of what this thread is trying to do but thought I would share. After doing the best I can do with stock speaker locations, I will probably do something similar with my touring.

[Stereoinstaller1]

I too am a fan of 2 way front stage...active, of course.

Quasi-aperodic tapered quarter wave tubes. Excellent response down to 60Hz @ 125db, but crossed at 75Hz @ 24db/oct:

[Mark185]

I too am a fan of 2 way front stage...active, of course.

Quasi-aperodic tapered quarter wave tubes. Excellent response down to 60Hz @ 125db, but crossed at 75Hz @ 24db/oct:

Time for me to bow down and say, "I'm not worthy". The enclosure concept is very cool and not something I would have dreamed of trying.

[dogkiller]

Is it possible that my touring has no rear amp? I have a blank space with just the wiring all coiled up where the cd player and amp goes.

My radio gave up the ghost. So I have replaced it with an aftermarket. So now I have a radio and would like to make it sound better.

Is there a way you guys could summarize this so this so the layperson can get a little more perspective without having to read through all the technical aspects of it? PLEASE!

[attack eagle]

no. that's what ths thread is for.

this is as untechnical as it gets when you get to this level of discussion.

did you actually take the plate off the wall and look for the amp? it is behind the wall, not in front of it.

[Mark185]

Is it possible that my touring has no rear amp? I have a blank space with just the wiring all coiled up where the cd player and amp goes.

My radio gave up the ghost. So I have replaced it with an aftermarket. So now I have a radio and would like to make it sound better.

Is there a way you guys could summarize this so this so the layperson can get a little more perspective without having to read through all the technical aspects of it? PLEASE!

Like AE said, the whole point of this thread is to help explain the technical concepts to someone with little or no background modifying audio systems. Sorry, but that means you can't come into the middle of the thread and ask me to simplify the language. I have purposely started with some basic concepts and worked up to more complex technical explanations as I go. Luke is doing the same thing. If you just want a summary, I can't do that yet. I am not done measuring things and deciding what to recommend. The motivation for doing this is a desire to give something back to this forum because it has helped me learn how to maintain and mod my E34. It is also intended to prevent some of you from falling prey to the type of BS mobile audio salesmen fed me when I was young and did not know better. There are some good salesmen and installers out there but my experience tells me most will tell you anything to get the sale and not care if you got value for your hard earned $$.

If you want a quick recommendation without waiting for me to finish, I say buy an aftermarket amp from an honest shop and have them install it along with a decent set of two way component speakers up front. Or find AE's thread about bypassing the factory amplifier and do that yourself. That would still involve installing an aftermarket amp to go with your new head unit. Your question does not give me the sense that you can do the work yourself yet. If you want to follow along with what this thread is about, you have to put the time into reading it and trying to understand the concepts. You also have to be willing and capable to tackle the install yourself.

I would move through this faster if I did not have to balance this work against spending time with my wife and kids, fixing stuff around the house, and actually getting my touring back on the road. Last weekend was focused on installing used Billy Boat exhaust, poly rear subframe bushings and M5 sway bars. (Thanks GIANUCCI for the help!) This weekend, I will try to take some pictures of where amp is located and wiring in the back of the car as I get ready to tap into the harness for the head unit signal wires and lines going out to the speakers. I ran into a snag with the Lanzar crossover. It did not work properly when I set the switches for just the front channels as input. It worked fine when set for front and rear inputs but I sent it back to be exchanged for a unit that has no flaws. The Amazon dealer I purchased it from has been responsive so far and if this goes well, I will recommend them.

[attack eagle]

oh, i posted pics of the touring amp location a long long time ago. I'm sure he didn't unbolt the cover plate and is looking at the phone harness that is usually left coiled up on the floor in the cubby area.

[Stereoinstaller1]

Here is where the Touring amps are:





Take that panel out, there is a bunch of room.

[Mark185]

Luke, it looks like some of the Exile amplifiers can be configured for bandpass active filter operation. This is a feature that seems to be disappearing from a lot of the amplifiers on the market today. I am not familiar with Exile. Just out of curiousity, are they priced near the mass market offerings from companies like Soundstream? I ask because Soundstream also makes an amp with bandpass active filter capability built in. I like the fact that the Exile crossover filters are 18 dB per octave.

[Stereoinstaller1]

Exile is/was the brainchild of disgruntled ex-Phoenix Gold employees.

I am no longer thrilled with it, but I was the 2nd shop in Oregon to sign an actual dealer agreement.

The bandpass functionality of the older amps is simply a "subsonic" filter...but yeah, the steeper slopes are way better IMO, that is why I use so much Audiocontrol stuff. 24db/oct FTW!

[dogkiller]

Like AE said, the whole point of this thread is to help explain the technical concepts to someone with little or no background modifying audio systems. Sorry, but that means you can't come into the middle of the thread and ask me to simplify the language. I have purposely started with some basic concepts and worked up to more complex technical explanations as I go.

I did read through most of this. I just did it in a couple different settings over a span of a week or two. And when I asked for a summary I had forgotten that your work was still in progress. That was my bad.

The time I spend on my car is focused on getting it mechanically sorted out and right now the stereo is the least important part. I have just finished the suspension work. Then I have to decide what I’m going to do with the motor. But at least I have a working head unit now!

I am quite capable of doing the work myself if someone like yourself and others here have done the leg work. (Which I highly appreciate BTW.) I would not be into it enough to want to try and figure it out without the resource you are providing.

This is what I'm looking at were I thought the amp should be. Sorry about the attached photo. I'm still a noob at adding images.

[GIANUCCI E30]

I did read through most of this. I just did it in a couple different settings over a span of a week or two. And when I asked for a summary I had forgotten that your work was still in progress. That was my bad.

The time I spend on my car is focused on getting it mechanically sorted out and right now the stereo is the least important part. I have just finished the suspension work. Then I have to decide what I’m going to do with the motor. But at least I have a working head unit now!

I am quite capable of doing the work myself if someone like yourself and others here have done the leg work. (Which I highly appreciate BTW.) I would not be into it enough to want to try and figure it out without the resource you are providing.

This is what I'm looking at were I thought the amp should be. Sorry about the attached photo. I'm still a noob at adding images.

It looks like that is the Mobile phone wires (can't really tell.) The location for the factory amp was behind that carpet (unless that is behind that carpet..Can't really tell that either) However if the location is the same as the saloons then that's it. Read AE's thread on the subject for the location of it.

However let's say you don't have it. Your at an advantage. You can wire the car for sound minus the factory amp. But from discussing this with Mark and following the thread. This thread has a different purpose.

Definitely subscribed if the commish lets me go out a play this weekend open to be involved.

[Mark185]

I did read through most of this. I just did it in a couple different settings over a span of a week or two. And when I asked for a summary I had forgotten that your work was still in progress. That was my bad.

The time I spend on my car is focused on getting it mechanically sorted out and right now the stereo is the least important part. I have just finished the suspension work. Then I have to decide what I’m going to do with the motor. But at least I have a working head unit now!

I am quite capable of doing the work myself if someone like yourself and others here have done the leg work. (Which I highly appreciate BTW.) I would not be into it enough to want to try and figure it out without the resource you are providing.

This is what I'm looking at were I thought the amp should be. Sorry about the attached photo. I'm still a noob at adding images.

I get the part about making it mechanically sound before diving into stereo upgrades. I have done the same with my touring.

The amp in the touring is behind the panel in your picture. There should be some screws holding it in place. Remove them and all will be clear.

Sorry I am moving so slowly through this. When I was in my 20's and single, this would have been a 1-2 weekend project at most. Age, family, and home ownership all slow me down. Saturday, I was working on stopping the rust in my doors before it gets out of control. I spent all day Sunday in a 110 degree unfinished attic installing a ventilation fan on the gable vent.

As far as the remaining steps, here is what I plan to do:

1. Tap into the wiring behind that rear panel to feed a signal straight to the speakers without the factory amp in the circuit.

2. Take some frequency response measurements with factory speakers doing each speaker separately.

3. Install one of the Peerless 2" drivers in the dash locations and measure them.

4. Solder RCA connectors on the twisted pair signal wires coming from the head unit. Plug these into the Lanzar crossover.

5. Connect output of Lanzar crossover to an old Soundstream 6 channel amp I have laying around. Measure frequency response after playing around with crossover filter settings.

6. Time permitting, experiment with an Audio Control EQX crossover/equalizer inserted in the signal path before the Lanzar crossover.

The Amazon dealer I purchased the Lanzar crossover from has been responsive to the fault in the first one shipped. The took my return no questions asked and shipped a new one out today. They are listed as Gem Products.

[Yahweh]

bump

[Layne]

bump

Lol wut?

Are there any alternate locations for the touring amp? Or did some not use an amp? (mines a 9/92 euro) I cannot find any trace that there was ever an amp in the location specified. No wires, no mounting screw holes, nothing. It has an aftermarket amp, speakers, and wires. The original wires are still in the speaker holes, I just can't find the other ends.

[Mark185]

Lol wut?

Are there any alternate locations for the touring amp? Or did some not use an amp? (mines a 9/92 euro) I cannot find any trace that there was ever an amp in the location specified. No wires, no mounting screw holes, nothing. It has an aftermarket amp, speakers, and wires. The original wires are still in the speaker holes, I just can't find the other ends.

No alternate locations for touring amp. An earlier post on this thread from a member in Europe indicated that some of the cars in their market did not have the rear mounted Blaupunkt amp and probably used the head unit to drive the speakers directly. This seems to indicate there were two different wiring harnesses used for the stereo by BMW.

BTW, I have not abandoned this project. I just had to take a break with the hot weather in July making it difficult to get much done when I had the free time. This weekend was another bust. Yesterday, I spent most of my time repairing a blown water pump and bleeding the system. I have done this job many times and never had so much trouble getting all the air out before. Today was around 90 degrees and 90% humidity. (I know Texas has had it worse this summer but 90/90 is way past my tolerance. This middle aged body just does not work well in those conditions.) I took my kids out for some DVD's and hung out with them instead.

I have all the parts I need to get into the build but still need to make some measurements of the OEM speaker responses in their stock locations before going to the next phase. Hoping to make progress this coming week.

[Layne]

No alternate locations for touring amp. An earlier post on this thread from a member in Europe indicated that some of the cars in their market did not have the rear mounted Blaupunkt amp and probably used the head unit to drive the speakers directly. This seems to indicate there were two different wiring harnesses used for the stereo by BMW.

Then that is definitely what I have. I noticed in my Bently manual both stereo schematics were for 10 speaker systems, but my car does not have the traingle tweeters on the doors. So it had to be a system not available to the US market. I'm parting out an E32, and the plan was to install all 10 speakers and the amp from it. Looks like I'll have to bring the wires over too. Nothing is ever as easy as it seems.

[Mark185]

Then that is definitely what I have. I noticed in my Bently manual both stereo schematics were for 10 speaker systems, but my car does not have the traingle tweeters on the doors. So it had to be a system not available to the US market. I'm parting out an E32, and the plan was to install all 10 speakers and the amp from it. Looks like I'll have to bring the wires over too. Nothing is ever as easy as it seems.

FWIW, it is worthwhile to bring the wiring over. The unshielded twisted pair wire BMW uses for head unit to amplifier and amplifier to speaker connections is very effective at reducing or eliminating alternator noise. You would have to spend a lot of money on aftermarket wiring to match the OEM performance.