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jalanparker37 05-16-2011 08:38 PM

Z3 Amplifier upgrade question
Hey all, this weekend I upgraded most of the speakers in my 2000 z3 2.3 and later this week the Integral Audio 8" sub kit will be arriving. I have a Rockford Fosgate P200-2 amplifier given to me for free that I will install to power the subwoofer.

BUT, although the new sound with the new speakers and without the terrible ~5 inch stock "subwoofer" assembly is quite improved already, I have a feeling that a little more uumph will be needed from the stock amp, especially at higher volumes and speeds with the top down.

So, I've been reading the forums, and I just want some guidance about replacing the stock amp. It seems some people have used 4 channel amps, but they use the head unit to power some speakers and such. I don't want to go that route because that is too complex for me. I'm thinking about keeping the Rockford for the sub and just getting a new amp for the other speakers, although I'll consider one big amp that can handle it all. But I don't mind the space that extra sub specific amp will take up.

So, the question is, should I get a 6 or 8 channel amp? The speakers are as follows...btw I am pretty sure I do not have the HK setup since I don't see HK on anything:

2 floor midbasses - about 5.25 inches I think
2 door tweeters
2 door midranges
2 behind the driver seat 4" midbasses
5 inch subwoofer POS that I removed and will be replacing with the Integral Audio 8" subwoofer.

I thought I heard that the tweeter and midrange have the same connection, but maybe not. I don't really know. Please help me out here, 6 or 8 channel. I think I can manage pulling all the plugs (or cutting and stripping them) from the stock amp and putting them in the new one.

Also, one more question....I suppose I also need (passive?) crossovers as I understand that is done in the current stock amp? What will that cost approximately? Do I need one for each channel or pair? Also, it seems that some people also buy a rather large capacitor - do I need that, and what terminals is that connected to. Lastly, please let me know anything I might have missed or any other guidance. Thanks a ton!

P.S. I don't really want to replace the head unit unless there is a really good reason to. I have a DICE setup with my ipod in the trunk that works fine for me.

Mpire 05-16-2011 08:48 PM

5 channel amp would be ideal, but those are rare.

A 4 channel and a single sub amp also works.

However, the placement of the rear speakers in the Z3 mean you won't hear the rear speakers anyways, so why not just go without for a while and see if you miss them.

Then you can run a single 4 channel and bridge the rear channels for the sub.

They are pathetically small speakers and aimed at the rear of your seat.

jalanparker37 05-16-2011 08:54 PM

Thanks Mpire. I suppose I could give that a try. I sort of noticed that too, that I couldn't really observe the sounds from those speakers while driving. So does that mean that the tweeter/midrange just needs a single channel to drive?

Mpire 05-17-2011 03:43 AM

What you need to do is find some cheap crossovers on ebay and then pick up a 2 or 4 channel amp for the speakers.

I have to ask what speakers you upgraded to, as they should have come with crossovers and they should NOT be compatible with the factory amp.

The factory head unit is a pre-amp only setup, and requires an amp to function, so you really can't run the rear channels off the head unit, so you can nix that idea.

Personally, I think the factory head unit sounds just fine, the only downside is that some people complain about skipping, I don't have a skipping problem, but the roads in Florida are excellent and dramatically lacking potholes.

So you can go a few ways...

1) Get a 2 channel amp to run your front speakers and keep the mono sub amp you already have. (what my friend Mark is doing)
2) Get a 4 channel amp to run your front speakers and use the rear 2 channels bridged for the sub (what I am currently doing in the wife's car)
3) Get a 5 channel amp to run all 4 speakers and a sub (what I am doing in the SG)
4) Get a 4 channel amp to run all 4 speakers and add mono amp for the rear sub (what I am doing in the EB)

My friend Mark went with a 2 channel amp that was rather small. Here is a pic installed in the factory location.

jalanparker37 05-17-2011 05:47 AM

Ah, Florida. Can't wait to move there at the end of summer - yeah, beginning of summer would be better but the job won't comply with that. In anticipation I bought my Z3 :)

Because of these compatibility issues and my original desire to keep this project as simple as possible - in fact I was hoping to avoid messing with the amp - I went with the BSW stage 1. I have a variety of good mechanical, electrical, and car experience and skill, but no knowledge about car amps/audio systems so I figured I'd make it easy on myself and go with their "plug n play" solution. Since then I've read the thread below, so I know your opinions on the BSW...and also learned that a lot of people think the number 1 high priority upgrade should be an aftermarket amp.

Now that I know how easy it is to get to and change the speakers, I probably should have gone with something like Polks which would have come with a matched crossover, but I've already spent the money so for now at least, I'd like to keep them if possible/practical. The sub is coming this week, and I have that amp, so that should be another improvement. I figure after I also replace the stock amp, then I can re-evaluate the speakers if I'm not happy with the system.

But what I don't understand - even if you axe the rear speakers - then it seems that you have 6 speakers in the front of the car still, not four. Two in the floor - the 5 1/4s, and four in the door - the tweeter and that odd midrange speaker. In yours (and others who use 4 channel amps for everything but the sub) are you also axing the midrange in the door, so you are just listening to the tweeter and floor speakers (seems I can't do that with the BSW tweeter which compliments the stock midrange)? Or do you somehow run the midrange and tweeter off of one channel? If I am reading this wiring diagram right, it seems that the tweeter and midrange may already be running off the same channel (perhaps there is an internal crossover in the system)? That's what I don't quite get about how a 4 channel amp would work. I guess one of the above would have to be true, but I'm not sure which is the case.

Not really going for audiophile here, just want to be able to listen to music loudly while driving with the top down and enjoy it. Looks like that isn't an easy thing to do!

KevinR 05-17-2011 06:55 AM

As I understand the BSW speaker system, you are now tied to the factory amplifier. Their system does not have crossovers, it relies on the crossovers in the factory amp. At this point I would recommend installing the Integral Audio subwoofer and amp that you already have and then re-evaluate at that point.

Don't get hung up on the number of speakers; what you're really interested in is the number of channels. The 5.25" speaker in the kick panel, plus the mid-range and the tweeter in the door all combine to make ONE channel. The other side front 3 speakers make up ONE channel.

Each rear speaker is ONE channel. The sub can be ONE or TWO channels, depending on your car's configuration.

Epicurean 06-06-2011 06:21 PM

I'm quite anxious to learn more on this topic. I just purchased an '01 Z3 2.5. As of the date of this post, I've only had the car for 7 days. 95 degrees in Texas and I have a serious sunburn from 7 days of driving with the top down! But I don't care because I'm having a blast.

I'm far, far from having figured out the audio system. Sub was blown (knew that before I bought). I have a 6 Disc changer in the trunk that works fine. From what I read, I'm guessing I have an Alpine unit (not Blaupunkt) but even there, I'm speculating. Do I have an Alpine 6 disc changer married to a Blaupunkt head unit? No idea. Everything appears to be factory.

At this point I'm trying to evaluate my options before I dive in. Like jalanparker37 I want to keep my head unit and I also don't want to overspend if I don't need too.

My first observation was that more power (amp) might improve things. I'd like to add a sub for more "umph" but don't want to assume I should just throw one in. Which, by the way, I doubt I can just "throw one in". I suspect it's not that simple. Also like jalanparker37, I don't have more than just average knowledge of car audio systems. For grins I took it by CarToys and they wanted me to take out a second mortgage "to get it right". Really didn't seem all that interested in helping me figure out how I might improve what I already have, but I recognize that that's not their focus.

My speaker set up seems to be different from what you all describe. I have a longish grill on each door near the top, but no other speakers in the door that I can see. I have the 2 behind the seat and the now useless sub enclosure (which I disconnected so I didn't have to hear the buzz).

I've been trolling the forums here and trying to research elsewhere to see if I can find a solution that doesn't require me replacing EVERYTHING. Or spending $1000. Since I just bought the car last week, I don't want to push my luck with my better half by going nuts on add ons :-)

So - with all that said - if there are posts, sites, etc that you can recommend, I'd be very grateful.

UPDATE: OK - check that on the speakers. I was looking in the actual door for the 5 1/4" speakers and now realize they are in the floor board area.

Mpire 06-06-2011 06:26 PM

I don't comprehend why people are afraid of the amp.

It could not be simpler to change out.

Takes a few hours on a nice afternoon.

We have the wiring diagrams, and its all ready to go.

Just get an amp and isntall it. Its a great first project that doesn't require getting dirty to work on the car.

Mpire 06-06-2011 06:27 PM

Replace amp first.

Then speakers.

You can do it for dramatically less than $1000.

The only time that should cost you $1000 is when you hire someone to do it for you and they screw you.

Mpire 06-06-2011 06:51 PM

Just for fun, I threw together some stuff on They have good deals sometimes. I am sure you can find better ones.

This would be a major upgrade over the factory system, you could always spend more, you can probably spend less. Its not top of the line, but everything is an improvement over stock.

Here is an example of what you need to buy:

5.25 component speakers $149

6.5 inch sub $79

JL 360w 4 channel amplifier. $239

You will also need a trim ring for the sub: $12

Amp installation kit: $18

You will also need some RCA jacks: $3

Spade connectors: $3

You should also go to home depot and pick up some silicone...

GE Silicone 2.8 oz: $3.89

You can freak out and spend alot more, or you can waste a **** ton of money and pay someone to do it, but for around $500 you can replace everything with good quality, BRAND NEW stuff.

Its not hard. Just dive in.


droz3 06-06-2011 07:28 PM

A nice 5 channel amp is a Alpine PDX-5 / 5-channel car amplifier / 75 watts RMS x 4 + 300 watts RMS x 1

Mpire 06-06-2011 07:33 PM

Yup, thats a good amp.

Its also more expensive, but I love the PDX amps.

Can't go wrong with that!

Epicurean 06-06-2011 09:34 PM


Originally Posted by Mpire (Post 6114832)

This would be a major upgrade over the factory system, you could always spend more, you can probably spend less. Its not top of the line, but everything is an improvement over stock.


Thanks Mpire. Great suggestions. And all this will work with the factory head unit, yes?

By the way, wasn't fear keeping me from diving in. Just simple common sense. That is, sometimes it's best to do a little research first. That way when. I do dive in I know whether the water is 3' deep or 30' deep.

Mpire 06-07-2011 07:10 PM

Yes, you can keep the factory head unit.

Its not all that bad to be honest.

Its definitely not the weak link in the system.

Epicurean 06-09-2011 01:47 PM


Originally Posted by Mpire (Post 6114832)

JL 360w is on the way

Regarding the Kicker - it's a 2 ohm right? 10cvt654 is 4 ohm 652 is 2 ohm - so I need the 2 ohm, correct?

Am I driving the factory speakers and the kicker with the JL Amp? i.e. will the 360w support driving the front 5.25's, the door speakers, the 4's behind the seats and the sub?

Mpire 06-09-2011 02:23 PM

Get the 4 ohm sub if you aren't driving it with a custom sub amp.

Its the same sub really, just 4 ohm vs 2 ohm.

This setup basically deletes the rear speakers in the car. You will not miss them.

4 channels on the amp. 2 channels to the front components, 2 channels to the sub.

You can always add a dedicated sub amp later and then add some small rear speakers for fill.

The factory rear speaker are about an inch in diameter. They are truly a joke, and yours are probably dry rotted by now.

Epicurean 06-09-2011 03:04 PM

Sweet! Thanks.

I'm resisting the temptation to ask you lots of install related questions. Amp will arrive Monday. I'll just have to open up the "patient" first and see if I can figure it all out without being a pest. Haven't done a car audio installation since the late '70's. Seems guaranteed that a few things may have changed since then :)

I suppose my biggest fear is being sure I'm careful about having to do any cutting of wires. I will use the wiring diagram floating around the forums and be 100% sure what I'm doing before I start doing surgery. I'll prep a little this weekend by digging into the trunk to ensure I know where everything is situated.

"Measure twice, cut once" as they say.

PS. Also ordered a USA Spec iPod Interface. I really wanted the DICE Mediabridge 1500 but with all the problems people seem to be reporting (including DICE themselves telling me not to buy it until they resolve the firmware issues) I decided to just move on. Hopefully I won't regret buying the Spec interface. Worst case scenario I use it for awhile until the DICE issues are solved and switch to that later.

Mpire 06-09-2011 05:10 PM

Feel free to ask questions.

The amp is the weak point in the system, for sure.

Replacing the amp is rather straight forward if you use the wiring diagram.

You will need to install some crossovers when you put in the new amp. Its almost easier to replace the amp and speakers together.

You can still do everything in the trunk, so it doesn't turn into a messy install.

You can get various crossovers here and there, however ANY speakers that you find anywhere, even the $20 Walmart specials will be better than the stock speakers.

Epicurean 06-10-2011 02:20 PM

Can you point me to documentation, how-to's or tips on how to be able to thread a cable from the cabin to the trunk? I've done some searching and dug through BMW TIS. But I'm not finding any visuals specific to my 2001 Z3 2.5i that can help me target my effort.

I received the iPod integration box today and the only thing that seems like it might slow me down is the process of getting the main cable from the front of the cabin (probably in the glovebox) through to the CD changer cable in the trunk. I don't mind doing the surgery, but I want to be sure before I start stripping off plastic bits that I'm focusing in the correct (most direct) area.

Thanks in advance for tips and/or pointers.

(By the way, if there is some obvious set of threads about this stuff that I'm somehow missing, by all means point me there and I'll refrain from posting all of my questions in this one thread.)

Mpire 06-10-2011 03:22 PM

Wait, are you using a stock head unit? If so, you don't need to thread anything or do anything in the cabin, ITS ALL IN THE TRUNK ALREADY.

If you are using an aftermarket head unit I would just run a 6 channel RCA down the center of the car on a coupe and across the drivers side and down the footwell to the hatch area through the grommet behind the driver under the carpet.

However, you don't need to do anything if you have a stock head unit.

Just look at this diagram and splice the leads accordingly into the amp and then wire the speakers into the crossovers. That's all there is to it.

Epicurean 06-10-2011 03:46 PM

No I'm not doing anything with the head unit. The iPod interface box has two cables. 1) The cable that goes from the box to the iPod and 2) the cable that goes from the box to the 6 disc changer cable in the trunk. The one from the box to the cd changer is the long one. The one from the box to the iPod is the shorter one. So the interface box itself has to be located in the cabin. But the cable from the box to the changer has to go through the cabin into the trunk.

So I'm really just trying to figure the best way to get that cable into the trunk. My suspicion is that I'll be going under the center console and then into the trunk.

I've just gotten home from work and was going to start working on this tonight. Taking my time. No reason to rush.

Hopefully this isn't a bad omen: I disconnected the negative battery lead so I could plug it back in to test the unlock code I have for the radio. Hadn't done that before and wanted to be sure I could actually unlock the radio before I got too far into things. Entered the code wrong. Now I have an "Code Wait" indicator. My understanding is that the only solution I have is to wait and hour with the key in position 2 and wait for it to clear itself then I can enter the code again. The dealership gave me 3 codes: 1 for Alpine, 1 for Pioneer (which are both the same code) and one for Blaupunkt. Of course, I really don't know what radio I have. I've continued with the assumption that since I have the CD Changer, I have an Alpine radio. But I'm not sure. So once the code clears, I suppose it's possible that I'll screw it up again and have to wait another hour. Jeez. :(

KevinR 06-10-2011 06:40 PM

I guess it depends on where you want to put your ipod while you're driving and the length of the cable from the interface box to the ipod. If you have enough cable length, you could mount the interface box in the trunk and then run the ipod cable to the center console.

Epicurean 06-10-2011 10:07 PM

Success - at least as a phase 1. I ran the long cable through one of the VERY small slots behind the subwoofer compartment leading into the trunk. The challenge was that the connectors on either end of the main connector cable. So i ended up cutting the end off the CD changer interface end. There were 6 small wires soldered to a small "logic board" like connector. I was pretty apprehensive about this because it meant I would have to solder the wires back together. But I couldn't really see a simpler way. Took a fair amount of patience but I was successful. I ran the cable underneath the center console through to the front passenger foot-well. At this point I was pretty worn out (95 degrees today in Dallas) so I left it for tomorrow to finish.

The phase 2 challenge will be to figure out the best location for the box (glove box I suspect) and then figure out how to run the iPod cable behind the radio to the drivers side where I'd like to run it into the unused accessory faceplate. I fear this will be a bit more tedious than I'd like. A bit more disassembly than I'm initially comfortable with.

Bottom line - it works. Great to be able to use my iPod and my iPhone through the radio. That alone improved the quality of the sound. The JL Audio Amp will surely improve things further. That's next weekends project.

jalanparker37 06-12-2011 07:00 PM

Hi All,'s been a few weeks since I installed the Integral Audio 8" sub enclosure (after the BSW Stage 1 and sound deadening). My honest assessment is that the improved sound is probably worth the money if you don't want much hassle and don't want to listen at blistering high volumes with the top down. The system sounds good on *most* songs (songs with a lot of low end - try "Great Car Dealer War" by the Drive-by Truckers, with 3 down tuned guitars playing low on the neck - still get a bit mushy) and with a passenger on a trip last weekend I was too polite to get it at the limits of its loudishness anyway and he was more than satisfied with the sound with the top down. For a lot of people, this would be enough, even without the sub. But, I like to play my music LOUD and I'd like it as clear as possible at those loud volumes (I play guitar and have probably lost my hearing...either way I'm used to LOUD :D). Therefore, the BSW is not for me and will go on sale soon at a good price for someone who is looking for the BSW stage 1 as the final goal and NOT as a stepping stone to a future system with an after market amp. As I have found, and others on the forum have said, if that is your goal, skip the BSW stage 1 (which doesn't play well with amps due to no crossovers and other issues like using a tweeter/midrange)

Thanks to the advice on this thread and others, I went ahead and purchased new speakers and a new amp.

What I bought:

Focal 130 KP 5.25" midbass+tweeter component speakers, JL Audio 300/4 Slash Amplifier (4 channel class A/B amp), more sound deadening for the floor panels, poly-fil, and speaker baffles (may or may not use them or I may try both ways to compare). I'm bridging the rear channels to power my sub, and will get rid of the mono amp I was using for that purpose - to save space.

I am also going to ditch the 4" rear speakers. Behind the seats I can't hear them anyway as Mpire and others have suggested.

The amp is coming Monday. Today I went ahead and hooked up the midbasses and disconnected the amp, wired my RCAs, and the crossovers. Everything in the trunk is ready to quickly accommodate the new amp tomorrow.


How do I wire the new tweeters in the door panels?

I am using the stock "midrange" wires to the tweeter terminals of the crossovers, as suggested here: (I have the non-HK). But, at the tweeter in the door, do I also use the midrange wires? Because it seems like there is an internal crossover that sends some frequencies to the stock midrange wires and some to the stock tweeter wires. The colors for the wires that connect to the midrange speakers at the door are different than the colors from the old stock amp (and that I have connected to the crossover tweeter terminals).

I'm guessing the answer is one of the following, but it may be something else:

1. Just use the stock midrange wires - because perhaps only the tweeter has a reduced frequency range and the midrange does not?

2. Solder the tweeter and midrange wires together to pick up the whole frequency response meant for the new tweeters.

3. Run my own wire; or run wire from the midrange wires at a location before they are split by the internal crossover - possibly the unmolested midrange wires can be found in the kickpanels?

4. Something else...

Some help on this question would be very much appreciated! Thank you - this forum is awesome.

jalanparker37 06-13-2011 09:13 AM

So....this morning I did some testing with my multimeter and a 9V battery.

Here's what I found:

The midrange wires in the trunk only pop the stock midrange speaker and not the stock tweeter. Likewise, only the impedance of the stock midrange is seen by the multimeter.

BUT, there were a couple of pairs of wires (yellow w/green stripe + yellow w/brown stripe and blue w/green stripe + blue w/brown stripe) that were not included on the wiring diagram: (non-HK).

The thought occurred to me briefly that those may go to the factory tweeters such that the crossing over for the midrange and tweeter was actually done at the amp. However, those wires do not pop a tweeter and do not have an impedance - so I don't think they are hooked up to a tweeter.

This seems to confirm that the midrange wires at some point in the car between the stock amp and the stock midrange/tweeters that the midrange wires enter a crossover of sorts and send some frequencies to the stock midrange speakers and others to the stock tweeters.

I'm just concerned that connecting my aftermarket tweeters to the midrange wires is going to result in only some of the frequencies I want going to them. Just wondering what the answer/solution is from some of you who have installed aftermarket component speaker sets.


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