Bose system blues...
 

OK, I'm posting this because when I went through this last weekend, I could find almost no info on it.

The Bose system is a pain in the ass to upgrade or replace. Let's start with that.

Apparently, if you buy a new fancy head unit (I got a Sony Xplod mp3) then it will not work with the Bose speakers. The ancient technology of providing an amp for each speaker (5) has to be painstakingly bypassed.

Now, the door speakers aren't that tough. We rewired those and put in some new 5 1/4" Pioneers that sound decent (AFTER being rewired to bypass their own individual amps <gag>).

But for the rear, I like the acoustic wave tubes. I think they are unecessary, gaudy, and a bit non-practical (like alot of things about the FD ;) so I wanted to keep them.
Also, I didn't want a strip of bare metal back there, or for the wave tubes to be non-fuinctional and just taking up space....

The two 6-3/4" speakers that are in the bass tubes are a bitch to simulate -because they face each other flush, touching- and most nice, new speakers will not face each other flush because of that gay looking middle part that is so common now.

SO, I had to go with some low level pioneers that were 6-1/2" and put them in with some padded tape so they wouldn't rattle, and guess what? It sounds like ass.

I guess people that upgrade the Bose just tear everything out. Cause I couldn't find one single thing on the net or the forums about what I was trying to do.

Has ANYONE found replacement speakers that will handle the load of a new head unit with pre-amp outs and yet still fit in the tubes and sound good?

Cause these pioneers sound like crap and I'm going to have to go back in and dissect the tube again....

Help?

I don't get it
if you go to the interrior/audio forum the top stickey post has a wireing diagram.
the only amp it shows is for the center channel. and it shows that amp running right off the line level outputs from the stock head unit.
From what I see teh door speakers and wave table both run off the power from the head unit.
I think you are wrong.
also you should be OK powering the wave table from your head unit as long as you don't play it TOO loud all the time.
most head units don't have that much power.

I personally can't say I installed a stereo in this car yet. I just ordered one today though. I figured it would be a bitch too untill I saw the wireing diagram.
see if that helps straighten you out.


anyone else installed a stereo in their car and retained teh stock setup for speakers and wireing. IE only upgraded teh door speakers and headunit?

fill us in is this real hard?

Leprechaun, One way to keep the Bose rear tube is to keep the Bose speakers in there, and drive them with an adequate amp. the load will probably be too much for most amps, so try running both speakers in series off of one channel of your amp.

I have no idea what you should do about the polarities of the speakers since they are facing each other. I think that means they need to be 180° out of phase from each other. (plug the + of the amp to the + of speaker one, then the - of speaker one to the - of speaker 2 & the + of speaker 2 to the - of the amp)

Re: Bose system blues...
 

That's what everyone thinks :D
ANY aftermarket headunit WILL work. You simply need to make sure the wiring harness is wired (Just one wire needs to be bridged) so that the amps get power with the radio. You also need to make sure you install a power reduction box so that the hi-power aftermarket headunit doesn't burn out the amps.

Make sure to reverse the polarity on one of the subs. So connect one with positive from amp to psitive on speaker and negative from amp to negative on speaker.

Do the opposite for the other sub, so positive from amp will go to negative on speaker and so on. You may have to check the phasing with the entire system. so the Bose wave will work with and not against your other speakers.

Hope this helps:)

hey flybye thanks for the info.
I even looked at that wireing diagram and didn't realize there were external amps in there since it points out the center channel so well and not the others.

as for knocking down the power with a power reduction box, where do you get those?
can you recommend one?

I used something like this:
http://www.crutchfield.com/S-72eL56i...p?i=101PL2&s=0


Except you need an adapter to convert the RCA connector into a regular cable so that you can wire it into the wiring harness.

Honestly, I did the headunit change almost 4 years ago, and I can't exactly remember the box that Crutchfield sent me, but it IS along the lines of what I just showed you. You Need a box like this to convert the high level outputs. Instead of using the RCA jacks on the headunit, I did it this way simply because I wanted to be able to adjust the amount of volume that was transmitted over to the amps.

Doesn't the Schose harness adapter do all of this for you? It has line level adjustments for each amp from what I remember.. I should take a picture of it and post it. You still have to splice one wire in to power the amps on with the stereo, but other than that it is plug and play afaik.

Matt

OK, reversing the polarity in the tube! Why didn't I think of that?!! .... Thanks I will give that a try.

BTW, yes it's more than just the center speaker with its own amp. All the speakers have it...

O.K. lets see if I can clear some things up. For 6 years I have been a custom stereo installer at various shops around Houston. I have won or been directly associated with an IASCA or USAC world championship car for the past 5 years and I built a van for Rockford Fosgate last summer. I hope I am qualified enough to answer this question. The factory Bose stereo only supplies power to the center channel directly. The door speakers are enclosed in their own housings with their own respective amps. The "Bose Hose" in the back also has it's own amp. This enclosure is referred to as a transmission line although Bose added their own twist to it to make a bandpass transmission line enclosure. The long side of the tube is 1/4 the total wavelength of the lowest frequency that they want the sub to reproduce. The shorter side is 1/3 the length of the long tube which corresponds to to uppermost frequency that the Bose engineers want the sub to play. When you put these two tunings together the system plays everything in between this range. damn that was technical and confusing! Bose designed this to work ONLY with the speakers that they have installed in it. Some other speakers may work albeit no one will know how good until someone trys it. The thiele/small parameters of each woofer will determine if they will or will not work. Since both speakers are facing each other, one of them has to be reversed in polarity from the other to be moving in the same direction at the same time or they will cancel each other out. You can't just reverse the polarity of the whole assembly and expect it to sound better. The pioneers probably do sound like crap in that box. They are also 4 ohm speakers vs Bose's 1 ohm units. Don't mix and match unless you change power source too. If you want to keep the factory Bose tube in the back then a way needs to be found to adapt the Sony headunits preamp output to the Bose's input so you can still use their amp and speakers (subs). Luckily there is an adapter available from some of the better highend car stereo shops. I can still get one but I am in Houston. I don't remeber the price since I changed professions at the beginning of the year. I still have ties though. If your brain didn't already explode I hope it helps you out somewhat. Sorry for all the technical crap.

Fred

What I meant was that I tried that Scoosche adapter, and it a joke! It's just a bank of variable resistors! $40.00 bank of resistors!

So, I went a less expensive route & installed 1.4 Ohm resistors in series with the speakers. It worked, but IMO the best way to do this is to replace the front speakers, remove the center channel amp, & replace the center speaker. You may have to add resistance to that circuit to get the desired volume. Then run the two subs in series to get a total of 2 ohms & drive them with one channel of a 100 Watt amp (Fosgate?). ALSO, wire the two subs in series, but reversed polarity from each other just like I spelled out above.

Enjoy,
Eric.

If you want to upgrade the head unit in a Bose system and retain the Bose speakers there is really only one cool way to do it. I have done it and helped some other people with it and it definetly works.

It will only work properly with head units that have the folowing features:
4.5V or higher line level RCA outputs.
Dedicated (4.5V or higher) line level RCA Subwoofer output .
EQ and Crossover functions for main speakers and sub built into head unit.

These features alow you to properly drive the bose amps and fine tune the system and especially the sub for optimum performance. The end result is sound far better than the way it sounded stock.

Some Kenwood Excellon head units (as well as a some others brands) have all of the above features. The choices are limited but available if you shop carefully. (I am using a Kenwood Z828 MP3 enabled head unit.) If you check Crutchfield you will probably find several head units that have the required features.

Then you need a P.I.E. PDC-LOC4 diferential converter

http://www.pie.net/sec12sb4.htm

This wires the front speakers to the Front RCA outputs of your head unit and the Subs to the Subwoofer RCA outputs of your head unit.

Wiring is made easier if you buy 2 wiring harness adapters. These are availble from Metra or American International and can be found at many autoparts stores an/or stereo shops. You need 2 because you need to steal a wire from one of them to gain acess to the Bose Amp turn on wire or your amps won't turn on.
If your head unit has variable illumination or you want to illuminate an aftermarket guage etc. you can steal another wire to gain acess to the variable dimmer circuit as well.

You also need an antenna adapter to connect the radio. Use the larger of the two antenna wires.

That is really about it and it works and sounds quite good. The key is in the ability to set high pass crosover points for front speakers and low pass crossover points for sub, control subwoofer output level and eq for optimum sound. If you want better you need to replace all speakers and use outboard amps.

By the way the center channel speaker has an outboard Bose amp below the center console. You dont have to worry about it though because it is already wired into the L&R front speakers so that it plays a sumed mix of both channels to reinforce center imaging.

Hope this info helps some of you.

Wrong-
The BOSE head unit does NOT directly power the center speaker (or for that matter does the std head unit) there is a center amp (mounted under the dash next to the Glove box in both systems) I know I had to replace mine. The amps are different for both systems and NOT interchangable

Just deleting a double post.
Not sure how it happened.

Any one want to sell their old Bose "crap"?
i.e. center, and right speakers and amps.

Ok, just an update. Reversed the polarity just now and it sounds a LOT better. Not perfect (like I wanted) but no longer sounds like ass and I can actually crank up the d-bass a little without cringing.

Thanks for the help. I wish I had asked before I started any of this (hehe) but I never imagined having any trouble like this replacing a stereo...

Never had a probelm with mine I had a mini disc head unit and 10 disc changer hooked up to the bose system, in the process of pulling that wave speakers out now since I just bought a 8" RS amp bazooka tube. I guess I have to buy new carpet for the rear which is probaly like 100 bucks from mazda lol

Just to wrap this thread up to help searchers. I put an after market head unit in this weekend. In order to get it working with the factory amps and speakers, I first had to connect the remote out wire(on the head unit) to the amp relay power wire on the factory harness, then I bought this 40$ black and orange (no real name ) box from Best Buy. It had inputs and out puts for 4 channels to convert line level outputs to amp level inputs. It also had gain controlls on it for fine tuning. Just go to bets buy and tell them what your trying to do. they had it right on a shelf with wires and other adaptors in the car stereo section.
worked great. Well worth the money.

I plan on replacing the whole stereo within the next two months, but I was wondering if it is possible to use the Bose amp for the center channel speaker to power an aftermarket 2" or 3.5" speaker. It's almost impossible to find an amp small enough to power just a center channel. Alpine sells a whole center channel setup that comes with a 35x1 amp and a 2" speaker, but the speaker is in a dash-mount housing; I'm not sure how easy it will be to remove the speaker, and the whole setup retails for $200. I don't want to pay that much just for the amp I need for the center channel speaker, so it would be great to use the Bose amp, since it's so small. Also, on the issue of wiring an aftermarket deck: whether you want to keep the Bose or not, it may be much easier to just rewire the whole car. I'm not keeping any of the Bose pieces, but, if you think about it, the wires have been there for 7-10 years, depending on which year FD you have, so it'll be worth it to redo them all anyways.