Upgrading the E34 Stereo Tutorial

[Layne]

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.

That's good to know. The aftermarket setup in there now just uses household speaker wire (and lots of masonite and hot glue). I'm removing it party because the amp is under the seat and will prevent me from installing my electric sport seats, and partly because it sounds like crap and makes a loud pop every time I shut the ignition off.

[shu328]

Just want to say this thread is clutch... I'm sub'd for sure.

I do have a good amount of electrical knowledge in industrial controls... but I simply get lost in audio speak... Always been a SQ-whore, but never really knew how to achieve it, technically speaking.

This thread has helped me bridge some of the gap and start to understand the "how" and "why".

Thanks a ton to you both for investing the time & effort to test, evaluate, and report your findings.

[MaxSteel]

If anyone here wants to replace the front stage speakers (the stock amp has to go) and wants a clean install, I recommend the Eclipse sc8355. The mids and highs fit perfectly in the stock locations :





And the crossovers can be wired easily to the stock wiring. I've placed them where the stock amp used to be:



No hassle at all. They sound very clean, especially for the money.
I had to make some adapters for the midbass's though, since the holes were a couple of mm off. Not a big deal.

Where did you get yours? I can't seem to find them online too easily. Also, are you running them amped or not? I'm not planning on amping whatever I replace my speakers with, for now.

Thanks for the help

If I get a 2-way component system can I still keep the stock mids?

[Schneider]

Yes I run them with an amp and got them here but now that you mentioned, I see they are nla. I've seen them on woofersetc.com/eclipse sc8355 but they are double what I paid for them. Sometimes they pop on ebay, maybe local cl. They are great sq speakers for electronic music, but they don't really like playing rock and classical, since the mids and highs have a solid aluminum cone. Planning to replace them as soon as I have the $ for what I want.

Imo if you want to go 2 way, with a decent set you won't feel the need of having those mids there, especially if you are not planning to use an amp right away. I'm guessing you're planning to use the headunit for powering the replacement speakers right? What headunit will you be using if you don't mind me asking?

Two way comps are plenty that fit in the stock locations.
I recommend you to lurk here and here. You can find good deals on quality speakers and usually everybody is very helpful if you have a question. If you find something and have doubts about buying it pm me or post here maybe others can chime in.

[MaxSteel]

I currently have this head unit:
http://www.crutchfield.com/S-lSOmyda...-CDE-9852.html

It appears to have a 16watt x 4 internal amp

If take out the rear speakers would it be possible to use all the power for just the front components? instead of using the internal amp 16x4, do something like 32x2?

[Mark185]

I currently have this head unit:
http://www.crutchfield.com/S-lSOmyda...-CDE-9852.html

It appears to have a 16watt x 4 internal amp

If take out the rear speakers would it be possible to use all the power for just the front components? instead of using the internal amp 16x4, do something like 32x2?

No. The internal amps in most head units already use what are essentially bridged channels to get 16 watts X 4. It is not possible to bridge them again to make 32 x 2. Just buy a decent used 25-50 watt per channel amp and mount it in the rear where the original OEM goes. Look on classifieds on diymobileaudio dot com if Ebay worries you. A used Alpine amp would mate easily with your head unit and sound much better than the built in amps. I have one in great condition if you are interested. PM me for details.

If you go this way, the issue becomes how you hook that amp up to the factory speakers. You either have to do the amp bypass mod described in another thread by Attack Eagle or do something like what I am doing on this thread - install an active crossover filter and a 6 channel amp. I have not made any progress on this project for many weeks. A combination of mechanical problems with my touring and health issues have slowed me down. Hurricane hitting NJ this weekend is not making it easier to finish.

[Schneider]

I currently have this head unit:
http://www.crutchfield.com/S-lSOmyda...-CDE-9852.html

It appears to have a 16watt x 4 internal amp

If take out the rear speakers would it be possible to use all the power for just the front components? instead of using the internal amp 16x4, do something like 32x2?

Like Mark mentioned you can't bridge the integrated amp. Imo that hu is great but has to little power for a set of comps. You can have a great condition used Alpine amp(to match your hu) for little money, so I suggest you to look for one if you want to truly enjoy your music.
There is also the KTP-445 power pack from alpine if you want to look into it. I'm not sure if its compatible with your hu though.

[M Quick]

I'll say thanks to M20E34 and Mark too, you guys are great and i'm happy to read and learn from everything you guys have shared with us! I'm also one of those SQ-guys that wants the best audio though have not much understanding at all in the talk you guys are sharing, until now that is, i'm understanding more and more as we go, i understand some things i need to change in my audio system now to improve it even more and that's fun!

I might aswell go ahead and evolve the discussion and ask about other aspects of a car audio sound system, if you guys don't mind!

A question for you M20E34, how have you routed your pow cables and where have you put your ground? Is the wires you have pictured enough for the length you've used from the battery? I'm asking because i got really beefy cables (which i don't really like, because they are in no way easy to route as they are not really flexible (4 gauge? 50mm)) and my amplifier location is not the optimal place to be if you want to use more amps and crossovers (i have my stuff where the oem jack "hoist" is etc which is not a good place due to ventilation/space).

Also i may also go ahead and ask you guys if one of those huge caps do any good? I got one and i was told they do their thing and i've had one installed since ages, i would want to get rid of that too, if they don't do anything. Fortunately it was free when i got it so that's why i have one in the first place.

And a couple of other question that popped into my mind, speaker cables and the RCA-cables, where have you guys routed them through the car, shortest way possible or any specific location?
Also what gauge cable is enough for the speakers? Or is the stock wiring enough? I'm using 16 gauge, atm.. and again i'd be glad to go down in size if thicker wires don't really matter.

How do you guys prevent generator noise or the like?

Sorry for all the questions, but i've read so much stuff on the net and pracitcally everywhere and i have yet to find a reliable "source" to get answers on these questions and what really matters, seeing as you guys are true car audio enthusiasts, i figured i might aswell ask! Don't be afraid to point me off if these questions are too dumb hehe..

Thanks

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.

Click your picture in this post to see my paint skills showing where the audio harness goes (red) and where the plate that hides it is held in at (green), IIRC those are the "bolts" holding it there, some of the "bolts" are hidden behind the sound insulating material and my point in where to the bolts are located may not be where they really are, but if i remembered correctly that's where they are, anyways, you'll see what to remove to get that plate with the sound insulating material off to reveal where the harness goes too, the other cables in your picture (that i didn't mark) are for the OEM GSM telephone option.

On cars like mine that didn't come with an amplifier, doesn't have any of those harnesses, i say this because people in the future may want to know how to easily check it up.

[Mark185]

A question for you M20E34, how have you routed your pow cables and where have you put your ground? Is the wires you have pictured enough for the length you've used from the battery? I'm asking because i got really beefy cables (which i don't really like, because they are in no way easy to route as they are not really flexible (4 gauge? 50mm)) and my amplifier location is not the optimal place to be if you want to use more amps and crossovers (i have my stuff where the oem jack "hoist" is etc which is not a good place due to ventilation/space).

Also i may also go ahead and ask you guys if one of those huge caps do any good?

And a couple of other question that popped into my mind, speaker cables and the RCA-cables, where have you guys routed them through the car, shortest way possible or any specific location?
Also what gauge cable is enough for the speakers? Or is the stock wiring enough? I'm using 16 gauge, atm.. and again i'd be glad to go down in size if thicker wires don't really matter.

How do you guys prevent generator noise or the like?

Thanks

Your welcome. M20E34 may feel differently but I usually use 4 gauge wire to supply power to the amplifiers. The proper gauge to use depends on how many amperes of current your system is going to require to make its rated power. I don't do installs with 1000 watt amps and 4 gauge works well for me. I don't really recommend going down in size to 6 or 8 gauge. I will see if I can dig up some info on what size wire to use for a given amount of current.

I like the stock amp location in North American cars behind the panel you show in your picture. Either that or on that panel as shown in M20E34's pics earlier in the thread.

The stock speaker wire in our cars is actually pretty good. It is not what a high end shop would install but if you are trying for maximum bang for the buck, keep the stock speaker wires. I think they would only become a limitation if you installed speakers that require big power to make them sound right. I am talking about a mid bass in the kick panels with a large excursion cone and a stiff suspension. That kind of speaker would need a lot of power to play loud and that usually means a lot of current. In that situation, a larger gauge wire than the OEM ones would be a good idea.

I don't like big energy storage capacitors. I think they are more marketing gimmic than actual effective hardware. If your car has a healthy battery and alternator and good thick wiring to the power amps, a capacitor is wasted money.

I like the stock wiring from the head unit to the rear amp in the North American cars. It is what is called unshielded twisted pair wiring and this is very effective at reducing the amount of alternator noise that gets into the system if you have the right kind of head unit and amplifier. The explanation is very technical for a beginning enthusiast but understandable. I wrote some long posts on www.diymobileaudio.com about this subject a couple of years ago. I will try to find a link if you want to know more. (mda185 is my forum name there.) For Euro market cars, I recommend that you look for unshielded twisted pair preamp cables. Shielded twisted pair is OK but not as effective as unshielded TP when your amplifier has a differential input. I have seen noise free installs in BMWs with coaxial preamp cables but in my personal experience, I have solved noise problems in an E34 by switching to twisted pair preamp wires.

Part of the reason is that with the battery mounted under the rear seat, there are large charging currents flowing through the chassis between the engine bay and the battery. These currents create magnetic fields that can induce noise in the preamp cables if they run through the fields. The other reason noise gets into long preamp cable runs is something described as 'loop area' by some respected mobile audio old timers, David Navone and Richard Clark. The explanation is more involved than I want to get into here. I also wrote some long posts about this on www.diymobileaudio.com under the name mda185. I find the most effective approach to reduce or eliminate noise in an E34 is to do the following:

1. Use 4 gauge wire for power amp 12 Volt DC positive and negative cabling.
2. Ground the amplifier(s) on a solid chassis point that has the paint sanded off for better electrical contact. I have used the rear seat center seat belt bolts for this successfully. I do not like to ground the amps directly to the battery. This can result in more of the alternator noise from charging currents getting into the stereo system.
3. Use some form of twisted pair preamp wiring from the head unit to the amps. Use a multi-channel cable with front and rear preamp signals in the same jacket if possible. This reduces 'loop area' problems. I use a 4 channel twisted pair preamp cable in my car. It not even a high end one. I think I bought it from Parts Express for about $20. It solved a nasty alternator noise problem in my old 535iM.
4. Use an amplifier with differential inputs that can subtract the noise on the twisted pair wiring + and - signals. The way twisted pair works, is it carries equal amounts of noise on the + and - wires. A differential amplifier input only amplifies the difference in the signals. The noise gets subtracted out. A coax cable has more noise on the outer braided shield by design. It is not as effective as twisted pair in a noisy electrical environment.
5. Install a new 4 gauge or thicker ground wire from the engine block to the chassis in the engine bay. Improving the ground connection between the alternator and the chassis can pay big dividends.

I have run the preamp cables along the side sills of an E34 and down the middle when I had the carpets removed. I found no difference in noise. The major difference in noise in my car was switching from coax preamp cables to twisted pair cables.

[cornflakecwl]

Some good info in here. Only thing I will dispute is about stiffening caps. Use one. They DO help keep current in the amplifier, especially sub amps. If nothing else, just put a half farad cap in close proximiry to the sub amp (ie shortest possible wire length between the amp and the cap). It will definately help keep your amp from loosing power amd clipping the sub.

Sent from my X10a using BF.com

[M Quick]

Thanks Mark and cornflakecwl for your insight!

M20E34, got any insight?

[stealthpenguin]

Gauge for power wires is determined by Amperage and Length of the run. 4GA is good for 95% of the installs out there.

[M Quick]

I see now that i said 4 gauge, when i meant 0 gauge (50mm2) it's really thick and if my eye messure is correct it's like 8-10mm of wire thickness inside the insulation. The speaker cables are 15gauge which are tiny.

I am very curious to m20e34 words about these things mentioned!
Do you also recommend 4gauge?

[sleeps41]

Thanks for all the good info being shared in this thread. I am looking at finding an economical upgrade for our speaker locations. I was looking at purchasing new speakers from bsw, but ouch on that price tag of $500. The kit had good reviews, but they don't have them available anymore on there site, plus I would rather spend that type of chip on other things. I am tuned in hoping that a better solution can be found here. I know there has to be a more cost effective solution. One thing that I have been trying to figure out and I know I have read it somewhere but cant find the posting on this but here goes:
1) We have established that we have a 10 speaker set up, but I do know not all of them are the same ohmage (I think that is how I can spell and refer to it). Has anyone researched what the ohm's are for each speaker as well as power rating?
2) Can anyone post the proper signal ratings for the door and rear tweeters, dash speakers, and kick panel speakers. I know there have been good educated range estimates, but does anyone have concrete numbers?
3) Has anyone tested the crossover rating (either 4 or 8 or some other ohms)? If so, what is the ohm rating for the crossover for the front and for the rear.
By establishing this I believe we can find some parts source to either a) replace the stocks with a decent replacement that doesn't cost $100 a pair, but matched up with the proper ohms and signal rating and b) possibly find a cheap yet decent 3 way crossover for the front and 2 way for the rear. I do know that this posting has been simplified for the average diyselfer, but if we can find parts from a vendor, and provide part numbers, then I think we can still be on track. If I am way off, then I apologize but these questions have been bugging me and I am sure that collectively we can come up with other solutions. So far I have been able to collect this info which is posted in other places but will share again, if my info is wrong, please correct me so that we can get the right info out there, but here is what the stock sizes are:
front tweeter size- 3/4"
dash speakers (mid range)- 2.5" (it has also been posted that 3" do fit but with slight modding)
kick panel (mid bass)- 5.25" (a larger size up to 6.5" can fit, but will require modding)
rear panel (mid bass)- 5.25"
rear tweeters- 3/4"

@M20E34- How is the venture on the crossover coming along? Would like an update.

I am currently working on the cd43 w ipod interface upgrade. Thanks to Mark185 for posting the links on post 1 that provided me the info on how to bypass the stock amp on my 95. Now I am hopeful in using my 5 channel Image Dynamics I5800 to power all the speakers and a sub that will be added later, but if we can figure out the crossover situation, then we can possibly eliminate the need to do the whole bypass and just purchase an economical yet practical set of crossovers that wont break the bank. Thanks again everyone and I will keep posted.

[Mark185]

After a long break, I am back on this project. sleeps41, I posted some frequency response and impedance curves for the dash midrange and door mounted tweeter earlier in this thread and will probably post again as I get into the next phase. IIRC, both the stock tweeter and midrange had extremely flat impedance measurement of ~ 4 ohms over a wide frequency range. This tells me they probably have ferrofluid in the voice coil gap because that generally smooths out the impedance response. Rare to see this in a midrange but not unheard of. An important point to consider is that the impedance of a speaker is usually not a constant value like 4 ohms. It usually changes with frequency and a passive crossover circuit must take this into account or the response will be wrong. That is why buying generic passive crossovers from any source is a bad idea. There is virtually no chance that they will be well matched to your speakers unless they were designed as a matched set.

The stock midrange and tweeter can probably have a very simple crossover between them because their impedance response is very smooth at all frequencies. I have not measured the 5.25" kick panel speaker but that is certain to have an impedance that is changing in the frequency range we want to cross it over to the dash midrange. That is one of the reasons why an active crossover for the 5.25" driver to the 2" mid is a good idea. It will eliminate having to compensate for the changing impedance of the small woofer in the kick panels.

Let me lay out the ground rules for this initial upgrade path again:

1. No subwoofer. This is intended to get the maximum possible out of the stock speakers and stock locations. Upgrades are definitely possible but beyond the scope of the first design I am going to describe. Before adding a sub, I would probably put 6.5" drivers in the kicks and see if that adds enough bass to satisfy. Using an active crossover filter between the woofers and the mids makes it easy to upgrade to larger 6.5" drivers in the kick panels at a later date.

2. Active crossover between the kick panel woofers and the in dash midrange driver. I wanted to cross over between 250-500 Hz because at higher frequencies, the wavelength of sound gets shorter and makes it harder to integrate the two drivers. The stock midrange has a built in roll off that starts at 1000 Hz. A better solution is to replace it with a newer design that has better response and efficiency. The best candidates I can find are made by Peerless. They have 3 models. Two are 2" full range mini woofers and one is 2.5" diameter. All three have a large Xmax. It is the max linear displacement the speaker is capable of before distortion becomes a problem. The Peerless drivers have 3mm Xmax which is close to the best I have seen in such a small driver. This bodes well for their ability to handle power and to cross over down in the desired frequency range. The cost ranges from $23-35 per speaker for the 3 Peerless drivers. This is up almost 100% from early this year but still much cheaper than the commercial system that is no longer available. Best places I have found to purchase are Parts Express and Madisound Speakers. Both have online stores.

3. Crossover frequency between the kick panel woofers and dash mounted mids will be 24 decibels (dB) per octave. This is to protect the mids and allow them to handle more power above the crossover frequency and it is to minimize the amount of overlap between the 5.25” speakers in the kicks and the mids. The active crossover I picked from Lanzar only has 12 dB/octave filters. I will get 24 dB/octave response by using an amplifier that also has active filters built in. Putting two 12 dB/octave filters in series like I intend to, results in a 24 dB/octave response. The trick is getting the frequencies aligned on both the Lanzar and the amplifier. Another way to get this capability is to purchase an Audio Control 6 XS. That has 24 dB/octave slopes and good input circuitry that can handle a wide range of signals. It is an excellent piece of equipment but it is more than twice the cost of the Lanzar crossover. I was able to purchase an amplifier and the Lanzar for similar money.

4. I am going to try designing a passive crossover between the dash mid and the tweeter in the sail panel on the door. This should be much simpler because the size of the components goes down at higher frequencies and the impedance of the drivers is fairly constant above 4 KHz. The only problem may be that the Peerless mids are too efficient and play louder than the stock Nokia tweeters. I won’t know until I mount some drivers and take measurements.

5. There is no way the modified system will have anything close to flat frequency response. The way the mid fires into the windshield and the tweeter fires from the door will make it impossible to get flat response. I am just shooting for the best possible within the constraints of the stock mounting locations.

6. Initially, I am only upgrading the front stage. I am not even going to hook up the rear speakers. I will provide tips on how to do this but won't do it in my car.

Power ratings for any of these speakers is not very important. It is what it is and we can't change that. The active crossover will do a good job of protecting the midrange drivers and the tweeter crossover will be high enough to protect that. The real important aspect is to have an amplifier that puts out enough clean power with low distortion. Distortion kills speakers faster than raw power. The driver most at risk is probably the 5.25" Nokia in the kick panels but they are easily replaced.

The approach I have described in this post will only require a 4 channel amp for the front stage if I can design a decent passive crossover for the midrange to tweeter. This makes this mod more affordable and will work with a larger selection of amplifiers on the market. The key feature needed is a built in High Pass active filter that can be set around 250-300 Hz. The Lanzar crossover will be set at 270 Hz for the High Pass to the dash mounted midrange. The combination will give the needed 24 dB/octave filter roll off slope. If you are shopping for an amplifier, I have a recommendation. It is the Soundstream Stealth Series STL4.500 model. Here is a review:

http://www.avhub.com.au/index.php/Pr...amplifier.html

This has the necessary active filters built in and is a compact design that will make it easier to mount in the stock amp or CD player location. It is also a bargain when compared to similar designs from Alpine, ARC Audio, and JL Audio. Those other brands make great products but I am looking for best bang for the buck here. The Soundstream Stealth amp is it. They also make a 6 channel model but you can purchase two 4 channel amps for the same money on Amazon. Get two 4 channel amps and you have the option to drive the rear speakers without major changes to my approach.

I will not be building this with the Soundstream because I have a couple of good amps on the shelf with the necessary crossovers but if I was buying new equipment just for this mod, the STL4.500 would be my first choice. I will be using a Cerwin Vega EXL 400.4 another excellent bang for the buck amp that has been out of production for a couple of years. It was designed for CV by Robert Zeff's company. He is the founder of Zapco but sold that company some time ago. His design firm used this basic circuit design for several commercial amps sold by Zapco, ARC Audio, and Cerwin Vega. It is larger than the Soundstream amp by a significant margin and will present some mounting challenges but is still a great choice for this E34 upgrade. If you find a used one in good condition, check it out but don't pay more than $150 for it.

[sleeps41]

Ok, I took out my front stock speakers out yesterday and wanted to add on to the info posted. Keep in mind that my E34 is a 95 525i with a production date of 9/94. Once I pull the rears i'll share the info as well.

front tweeter size- 3/4" Couldn't find manufacturer name- 4ohm rating
dash speakers (mid range)- 2.5" Nokia - 8ohm rating
kick panel (mid bass)- 5.25" Nokia -4ohm rating
rear panel (mid bass)- 5.25"
rear tweeters- 3/4"

Once I pull the rear panel out I will post the maker and the ohms of each speaker. Does anyone know what the wattage rating is for these stock speakers?

[Mark185]

Ok, I took out my front stock speakers out yesterday and wanted to add on to the info posted. Keep in mind that my E34 is a 95 525i with a production date of 9/94. Once I pull the rears i'll share the info as well.

front tweeter size- 3/4" Couldn't find manufacturer name- 4ohm rating
dash speakers (mid range)- 2.5" Nokia - 8ohm rating
kick panel (mid bass)- 5.25" Nokia -4ohm rating
rear panel (mid bass)- 5.25"
rear tweeters- 3/4"

Once I pull the rear panel out I will post the maker and the ohms of each speaker. Does anyone know what the wattage rating is for these stock speakers?

Wattage rating for stock speakers is not very important in terms of how to upgrade the system. That data is probably not available but just looking at the speakers, I doubt they are capable of handling more than 25 watts of continuous power. The tweeters in particular do not handle much power. The key is using a proper crossover filter. The filters keep damaging power levels from getting to the mid and the tweeter. BMW does this filtering in the stock amp.

When picking replacements for the stock speakers, power rating is still not very important. Music signals are not usually constant power. There are peaks and dips and unless you are cranking some bass heavy music as loud as possible, the average amount of power delivered to the speakers is not very high. Modern speaker manufacturers usually rate their speakers in terms of max power (watts) and average music power (RMS watts). In general, those ratings indicate the limits when the voice coil starts to overheat and melt the glue holding things together.

I would say the only time power rating is important for you to consider, is when choosing a subwoofer or mid woofer if you like to crank your tunes and love a lot of bass. Power rating for tweeter and midrange drivers is not nearly as important as determining the proper crossover frequency and best slope for that crossover. If we use a 24 dB/octave filter to the midrange at about 250-300 Hz, any decent 2-3" mid should work well regardless of its power rating. If we cross to the tweeter in the range of 3500-5000 Hz at 12 dB/octave, the same should be true. Stock BMW 3/4" tweeter probably should be crossed over at 5000 Hz or above.

Actual frequency response measurements of the stock speakers and recommendations from me are coming soon. Had some trouble getting my measurement equipment working after letting it sit for a long time but I think all is good to go as of tonight. I moved the software and hardware over to a Windows 7 machine supplied by my employer and I just finished sorting out the issues an hour ago.

[sleeps41]

Mark, you are correct about the wattage not being too much of a big deal. Especially if they are to be upgraded later. After doing some more extensive reading about this topic I realized that my amp is the 94-95 one, therefore it seems that I can't just pluck away the crossover in this thing (unless someone else has done it and posted it, but I have looked and have not come across it for this model). It would be ideal since it contains an active crossover, but the circuitry is a bit complex and not ideal for hacking. I will be looking at another option, perhaps the Lanzar crossover you mentioned. How has it been working out for you? This is the last piece of this puzzle I need to figure out in order to install my equipment. Everything is lined up, just have to figure out this crossover issue. Luke, any luck yet with that crossover you were developing? So close yet so far!

[attack eagle]

if it was a front battery car, id say 4. but for most 4 channel amps in the 30-50wx4 range, 8 is more than ample
now if you want a sub amp, sure, run 4 to a distro block then go to 8 for the last 2-4 feet per amp... not worth the $ or install hassle to run 4 to an amp for .05 volts

[Mark185]

Mark, you are correct about the wattage not being too much of a big deal. Especially if they are to be upgraded later. After doing some more extensive reading about this topic I realized that my amp is the 94-95 one, therefore it seems that I can't just pluck away the crossover in this thing (unless someone else has done it and posted it, but I have looked and have not come across it for this model). It would be ideal since it contains an active crossover, but the circuitry is a bit complex and not ideal for hacking. I will be looking at another option, perhaps the Lanzar crossover you mentioned. How has it been working out for you? This is the last piece of this puzzle I need to figure out in order to install my equipment. Everything is lined up, just have to figure out this crossover issue. Luke, any luck yet with that crossover you were developing? So close yet so far!

As always seems to happen, I ran into unexpected issues. The Lanzar crossover is good bang for the buck but has some limitations that keep me from strongly recommending it. The only way I can recommend it is if you use an amplifier that also has a high pass crossover capable of being set somewhere in the 250-300 Hz range. The reason is that the Lanzar crossover does not have symmetrical roll off slopes in this frequency range. The low pass section that would feed the kick panel woofers rolls off at 12 dB/octave as expected. The high pass filter rolls off at just 6 dB/octave. Nothing in their literature indicated this. 6 dB/octave is too shallow a slope to protect a small midrange driver in the dash. If the Lanzar crossover is used with an amplifier that also has a crossover filter that can be set to the same frequency, you will end up with an 18 dB/octave filter slope and that is OK for a small midrange driver. 24 dB/octave is better but I doubt the difference between 18 and 24 dB/octave will be audible to most ears. I actually built an amp board that mounts the Lanzar and one amplifier in the space normally occupied by the CD changer in a touring. I will post pics later today. Here are list of pros and cons for the Lanzar active crossover:

Pros: Low cost (~$100), Can be configured for a 3-way system with woofer, midrange, and tweeter. Midrange can be configured with bandpass filters. This is not a common feature in aftermarket active crossover filters. Individual output level controls allow matching of volume between woofer, mid, and tweeter even if they have radically different efficiencies. This makes it easier to install upgraded dash midrange.

Cons: Only 6 dB/octave roll off slope in midrange high pass active filter. Requires use of amplifier with its own built in crossover to achieve 18 dB/octave slope. Lanzar does not appear to have differential inputs on this model which means it could have problems rejecting alternator noise in some installs. Larger than most active crossovers. Might present install challenges depending on amplifiers you use and where you mount them.

I am going to suggest some alternatives that I have not personally bought and installed. The first is to check out the Soundstream STL4.500 4-Channel amplifier from their Stealth series. It can be configured with a bandpass filter for the midrange and could eliminate the need for the Lanzar or any other external crossover. The filter slope is 12 dB/octave which I consider the minimum acceptable for a small midrange crossed over between 250-300 Hz. This amp is available on Amazon right now for about $135 and seems like a good deal. Down side to using this amp is that it is only 4 channels and you probably need to use 2 for a decent install in an E34. Up side is that these are very small amps and mounting 2 should not be a problem. You will have to figure out a way to feed the signal from the head unit to both amps if you buy 2. It could be as simple as using a 'Y' cable to split the inputs from the head unit.

http://www.amazon.com/gp/product/B00...F8&me=&seller=

My preference would be to use these amps with an Audio Control EQX in front of them in the signal chain. The EQX has a built in 24 dB/octave filter that can be set to many different frequencies simply by changing a set of resistors inside. The resistors can be purchased online from many different sources. I like a company called Mouser and will supply part numbers and ordering info when I finish checking this out. I will set the EQX crossover filter to somewhere between 250-300 Hz and use it to feed a 4 channel amp on the high pass side for the midrange and tweeter. This will not require an external active filter like the Lanzar and it will not require a bandpass filter like the Soundstream model has. It will require the ability to set up a crossover filter between the midrange and the tweeter. Many amps have this ability. The Soundstream should still be a good choice for this. The low pass side of the EQX filter will feed a second amp used to drive the kick panel woofers. I will probably use a 3 year old Cerwin Vega amp rated at 100 watts per channel for this. Pros and Cons of this approach:

Pros: EQX has 24 dB/octave filter and 12 bands of equalization that can be used to further tune the install. It also has differential inputs that should make it easier to get a noise free install. It also has an extra set of output signal jacks that enable daisy chaining of signal processors or amplifiers depending on what your install plans are. It is nice to have this flexibility.

Cons: Cost is around $250-280 new and $125-175 used. I picked 2 of these up on Ebay a few years ago for $150 for the pair but prices seem to have risen since then. Does not have capability to do 3 way active crossover filter. That requires another crossover unit or an amplifier with built in active filters for the midrange to tweeter frequencies. The Lanzar active crossover is one possibility but we would only be using a couple of its filter channels. I think it makes more sense to just buy an amplifier that can do the crossover filter from midrange to tweeter in the 3000-4000 Hz range.

http://www.audiocontrol.com/t34/5248...Crossover.html

I will do a test install using one of my EQX units as soon as possible.

[Tenrac]

I upgraded my stereo based off of the advice in this thread, and I thought I would offer my impressions.

Here is the equipment that I am using.

Headunit: JVC KD-R730BT
Front stage amp: Soundstream STL6.620
Rear Stage amp: Eclipse 3650
Speakers: All stock, plus 8" JL Audio Sub.

I already had the Eclipse 3650, which is a 4/5 channel amp. I bought it used 5 years ago for $120.00, and it has been rockin like a champ in all 3 of the cars it has been in. I am using it to run the rear speakers and the 8" JL audio sub.

I needed a solution for the front stage, I wanted to keep all 6 speakers in the mix. I like simple solutions. In the original post, Mark mentioned the Soundstream STL6.620. It was exactly what I was looking for. It has plenty of power for the front stage and the crossovers on it are extremely tunable. It has a high pass for the tweeters, a low pass for the midrange woofers in the kick panels, and a band pass for the dash mounted mids. I am still tweaking the crossovers, and getting the gains balanced between the front and rear stage, but even before I started tuning the crossovers the front stage sounded 100x better than it did on the old stock amp. There are a few small cons to the Soundstream, one is the awkward shape and size of it, and the other is the limited amount of input options...you are forced to use RCAs. Splitting up the single "front" preamp output on the head unit into three inputs for the Soundstream was annoying.

Overall I am very very very pleased with the whole system now. I am using all of the stock speakers, and they sound pretty fantastic.

Ideally I would like to use a CD43 in the console because I absolutely can not stand the way aftermarket headunits look, but that would have added some more expenses to the system to get the same functionality that the JVC unit gives me...maybe someday.

[Mark185]

Wow, I have not been on the forum much in the past 4 months and I check in today only to find some action on this thread months after a long delay in my work. Tenrac, I am really glad to hear that you have had some success setting this up with the Soundstream amp. I think I told you that I bought two of the 4 channel versions before the holidays last year. I have not had the time to get back to this project but I intend to do something very similar to what you did only I will use the two 4 channel Soundstream amps instead of a 6 channel version and your Eclipse. I am interested in hearing what crossover settings worked best for you.

[Tenrac]

I will let you know when I get done tuning the crossovers. The front dash midrange and tweeters are still both a little too bright and I am getting a ringing type distortion from the lower woofers in the kick panels...can't tell if it is because the speakers have gone bad, or that I have some frequencies going to them that shouldn't.

This is also the first time I have ever tuned a crossover on a car amp, done it plenty if times on an amp rack...but it has been a while. Trying to remember all of my frequency lessons and also get a feel for the sensitivity of the pods.

[trsbmw]

This may be a bit off topic, but would like some advice regarding a problem I am currently having on my 94 530i.

All stereo components are completely stock, and about a week ago started facing the following symptom:

1: with stereo on, using all four bands (i.e. radio, tape, cd changer, and WB) at varying volumes, the left front mid and tweeter speakers (I couldn't perceive whether the kick panel speaker was doing it) begin popping and crackling, and eventually the entire front left channel turned off. It would intermittantly come back on. The volume of the stereo did not affect the volume of the popping and crackling, for example, even with the stereo volume set at an inaudible level, the popping and crackling were still evident. It even remained when I set fader to rear, or balance to right. On top of that, I smell a faint electrical burning smell from the head unit area, but no sign of smoke.

Hopefully someone has a good idea of where to look first, and whether it is most likely an amp problem, head unit problem, wiring problem, or any comination thereof.

Thanks in advance for any ideas...

[Mark185]

This may be a bit off topic, but would like some advice regarding a problem I am currently having on my 94 530i.

All stereo components are completely stock, and about a week ago started facing the following symptom:

1: with stereo on, using all four bands (i.e. radio, tape, cd changer, and WB) at varying volumes, the left front mid and tweeter speakers (I couldn't perceive whether the kick panel speaker was doing it) begin popping and crackling, and eventually the entire front left channel turned off. It would intermittantly come back on. The volume of the stereo did not affect the volume of the popping and crackling, for example, even with the stereo volume set at an inaudible level, the popping and crackling were still evident. It even remained when I set fader to rear, or balance to right. On top of that, I smell a faint electrical burning smell from the head unit area, but no sign of smoke.

Hopefully someone has a good idea of where to look first, and whether it is most likely an amp problem, head unit problem, wiring problem, or any comination thereof.

Thanks in advance for any ideas...

Sounds to me like the amplifier output stage of your head unit is damaged because you got popping noises in more than one speaker on left channel. The amp in the back has separate circuits for the individual speakers. Popping in more than one speaker points to the head unit. Smell from head unit is also strong indicator. Try swapping in another head unit. It is pretty easy to do.