Bose Speaker Replacements

[torchred]

I recently replaced the stock head unit in my C5 and ran into the powered Bose speaker problems so many others have had. I was unaware of this problem prior to installing my head unit and have been completly unsuccessful at finding a viable work around...

Moving along, I am looking to replace all the Bose speakers in the stock sound system. I have a '99 so the only speakers I am not able to run are the door speakers providing all the lows. Can anyone first suggest speakers to replace these powered Bose speakers? From personal experience, does anyone know what speakers best fit in the doors without heavy modification? Pictures are appreciated.

Thanks!

Matt

 

[AZMike]

The guy who did mine ended up bypassing the internal amps and connecting the external amp to the door speakers.

I got a subwoofer and a 4 channel amp with my new head unit and just used the stock Bose speakers. Sounds great now.

The back speakers are still hooked up to the head unit, but they really don't produce any sound due to lack of power.

 

[torchred]

I have read it was not good to reuse the Bose speakers since they are only 1 or 2 ohm speakers. Can't they cause overheating with aftermarkent amps and eventually fry the equpment?

Do you know how to bypass the internal amps? How much power are you putting to the door speakers?

 

[corvettecrazy]

www.crutchfield.com

they are amazing, will tell you what fits your car, and if you buy from them they include an instruction sheet for the install(vehical specific) and any necessary mounts and thing...check it out.

 

[AZMike]

I'm running a 400 watt amp (4x100). 2 channels to the sub and 1 to each door speaker.

I've only had the amp cut out on me once so far, but that was with the old battery and the volts were down to 10 (oops!). Other than that, I see no signs of the amp overloading when it's given the proper number of volts.

Anyway, the guy at Unique audio owns a Vette and does a lot of them. Speaker resistance is not an issue unless you drive around with the volume at max all the time. In which case, you should step up to a 4x150 amp. I went with the 4x100 since I don't need eardrum bleeding volume. Mine setup sounds great and drowns out anything else - even at 100 with the top down.

 

[VAmagred01]

I ran into the same problem......before the installer finished, he called me into the shop, explained the problem and told me the effects (i.e. bad-quality CD sound). He and also Crutchfield said that the only way around this is to replace all of the speakers. I'm ordering them from Crutchfield. The front sizes are 3-1/2" and the rears are 6-3/4" (correct me, someone, if I'm wrong) so it's pretty much up to you on how much you want to spend. I'm personally buying the Polk EX351's for the front and the Kicker K65's for the rear.

Good luck!
Kenny

 

[yellow_2002_germany]

I was looking at Crutchfield as well.

The speakers are direct drop in with the factory head unit?

 

[torchred]

I have ordered the 3 1/2 " Polks for the front and the 6 3/4" Polks for the rear. They should be in today & I will post my installation experience once I've put them in. Crutchfield says they should be direct drop in replacements but I'm not 100% sure the front speaker size is correct. I havn't pulled the door/speaker grill off yet but I find it hard to believe that there is only a 3 1/2" speaker hiding behind that big grill.

Matt

 

[VAmagred01]

I don't know if the aftermarket speakers will work too well with the factory head unit (per "yellow_2002_germany's" question). I have a Pioneer DEH-6200 deck currently running into the factory-amplified speakers. I have yet to order/install the speakers that I mentioned above. I see that "torchred" has beat me to it! Definitely let me know how they sound. The Polks should give you crisp, clean highs while the Kickers should deliver some nice punch and midrange! I will be ordering mine in a week or two.

 

[torchred]

After playing with the speakers and going through the trouble of pulling the door panels off I decided to 86 the polks and just wire passed the Bose amplifier. At first I just tried jumping through the connected terminals with the amplifier in line and it was putting power back through the system and causing some strange feed back. Needless to say all I did was remove the clip that holds the door wiring to the speaker wireing (it slides out), disconnect the wiring harness from the Bose in door amplifier and run a jumper wire from the 3 1/2" Bose speaker to the compressed 8" Bose wolfer. I replaced my stock head unit with a Kenwood MP3/Sirius head unit some time ago and until now havn't had any lows... the stereo now sounds as good, if not better than the origional setup.

Now, drawbacks... I have heard that the Bose speakers are either 1 or 2 Ohm speakers. I'm guessing this would mean that either the pair (3 1/2" and 8") in parpallel would be running at either 1/2 or 1 Ohm. I have a hard time believing that the stock head unit can run the speakers at 1/2 ohm stable all the time and at every volume. I could very well be wrong, this is only my opinion... I didn't have a multimeter handy to actually measure the speakers resistance. If the speaker is truely a 1 ohm speaker it is possible I/someone else could fry either the after market head unit or an after market amplifier. Those units probably look for a 4 ohm load and will see anything at 1 or 1/2 ohms as a short which could cause the unit to over heat and die.

Matt

 

[torchred]

VAmagred01... I don't recommend the Polk 3 1/2" that I ordered. My entire order will be going back to Crutchfield tomorrow... the Polk highs do not put out near as much sound as the Bose stock speakers. At least not without and after market amplifier. I have the Kenwood KDC929 head unit and I believe it puts out 50 watts per channel. This sounds really good with the Bose speakers.

I've decided I'm done with the stereo. On to performance mods for me. Anyone got a 3.47 rear differential for sale??


Matt

 

[VAmagred01]

Thanks for the info, torchred! I'm confused though. Where did the 8" speaker (woofer) come from? Was that a seperate purchase or was that already in your car? I take it that you didn't use the 6-3/4's as well?

 

[Bugster57]

Check this out, valuable info. That stock system is something else.
I don't mean good either.

Bose Stereo All you ever wanted to know

 

[torchred]

VAmagred01:

In each door you will find a 3 1/2" twiddler, a 8" reverse cone woofer, and a 100 watt Bose amplifier that connects to the 8" woofer. When you change the after market head unit, the 8" woofer stops working. I suspect this is because the after market head unit is not aware of the amplifier and does not send it a power signal to turn it on. When I pulled my stock head unit I noticed that there are two wiring harnessess connected to it. I believe the Bose Control Module (BCM) is run off the wiring harness that is more left and I believe some of these wires may be responsible for turning on the in door amplifiers. I do not have a good diagram so I'm not 100% sure how this actually works, this is just my suspicion.

I am going to pull apart my door again this weekend and try to layout a lowpass filter for the woofer. Also, if the woofer measures < ~3-4 Ohms I'm going to order a 50 Watt or 100 Watt wire wound 2 Ohm resistor from newark so it will be impedance matched with my head unit. Just to avoid excess heat in the amplifier. I will post a picture of my setup once it's complete and details on how to make the low pass filter for the woofer once I lay it out and put it together (tested).

Bugster57:

How do you read the info at the bottom of that document? It's a wiring diagram for something... it makes no sense to me. Best I can tell, it's got something to do with the BCM module and how it works with the in door amplifiers?? I was aware that there is not true tweeter in the car already (i've pulled the thing apart), however the stock speakers definatly sound significantly better than the Polk 3 1/2" full range speakers that are drop in replacements.

Matt

 

[Bugster57]

If this is of what you speak;
C4(9) TAN/BLK connect to C3(1) DK GRN
C4(10) LT GRN/BLK connect to C3(2) LT GRN
C4(11) BRN connect to C3(3) BRN/WHT
C4(12) DK BLU connect to C3(4) BLK
C4(13) LT BLU connect to C4(7) YEL

These are C5 wiring connector designations for the head unit.

FYI - adding a wire wound resistor will not help in matching the AC impedance of a speaker to the output amplifier.
Impedance matching in AC circuits (like a speaker output) is different than DC circuits.
You actually need impedance matching transformers and related circuitry to achieve this.
Read the link to the Bose tech tip in my post above.

The Bose system is a "complete system" bad as it may be it is difficult to hack it apart and use only pieces in addition to an aftermarket head unit. The speakers have onboard differential amps, the head unit outputs will not drive speakers sufficiently without these amps. The Bose system uses a BSP (Bose signal processor) located to the right of the go fast pedal under the dash. The BSP drives the amps and provides the crossovers for the system. If aftermarket setup is used I think the BSP must remain to keep codes away....
Usually the optimum setup is remove the headunit and speakers and install a "complete aftermarket system"
Crutchfield may have a harness adapter for the C5 now, previously they did not. That's where I would start to build a complete system.

 

[torchred]

My mistake, you are correct about impedance matching an AC circuit. I still don't believe the best option is to replace all the speakers in the car. The only reason I say that Is because I would more like to use the speakers in their current locations. Crutchfield only sells the 3 1/2" speaker in the door and no reverse cone woofers. A friend who does stereo installations told me infinity, like Bose, makes a reverse cone woofer however I have been unable to find anywhere to order one.

I think the best option in this case would be to replace the door woofer with another, properly impedanced, woofer to keep the door panel as stock as possible. Also, placing a good cross over where the Bose in door amplifier may be a good option. I am not looking for thumping bass, I would just like to hear some lows in the music I'm listening to. I'll leave the 'booms' to the kids in the ricers.

Matt

 

[VAmagred01]

Thanks for the info, torchred. It seems more in-depth than I thought. Looks like I'm going to have to take it to a custom shop to get it to sound like I want. I've been driving around today with the top off and it really makes me realize how awful this system sounds. I'll wait to here what you come up with before I spend $$$ on a custom system. Thanks again!

 

[Bugster57]

An effective way to boost output and bass is to add an amp to drive an additional sub and add additional piezo tweeters parallel to the rear speaker connections. Point the tweeters at the head of driver and passenger.
Some 6.5' aftermarket speakers even have moveable tweeters, swap out the rear stocks with those.

I've seen these at Crutchfield, several to choose from.

 

[torchred]

Bugster57:

Personally, I had an aftermarket woofer in my last car and it's just to much bass. I am not trying to boom all crazy when I'm going down the road.

As far as the impedance matching circuit goes, you should be able to use a 2 Ohm 50 Watt resistor in series with the speaker. I believe this issue comes down to the noise you will get form the speaker with the resistor in series. The frequency responce form the woofer is probably only 20 Hz to, at the most, 500 Hz. In this range the resistor should be sufficient in impedance matching the speaker impedance (though it will dissipate some power). The main issue in the AC circuit is reflection through the transmission line, in this case it's the speaker wire from the amplifier to the speaker. A 1 Ohm load will look like a short and most of the current will be reflected, out of phase, back into the amplifier. I believe raising the DC impedance of the speaker will help reduce the ammount of AC current reflected back into the amplifier. Even if you can reduce the current to the 1 - 1.5 Amp range you are prolonging the life of the amplifier as well as extending the ammount of time the amplifier can run before cutting out due to heat.

Let me know what you think, I'm all ears.

Matt