Anderson

Is the 2001 Bose Unit the same as the 1999,2000?

Can I use the posts describing the C4 and C1 wiring pinouts posted by 99HT?

Specifically, is the following info correct?

C4 pin9 (tan/blk) LF
C4 pin10 (ltgrn/blk) RF
C4 pin11 (brn) LR
C4 pin12 (dk blu) RR
C4 pin15 (blk) ground

C1 pin8 (dk grn) radio on

thanks for any advice.

Norris

Don't know if I can answer your question completely, however my 2001 Coupe came with an AM/FM/Cassette with the 12 disc changer in the rear. I purchased and had installed an AM/FM/CD head out of a 2000 Coupe. A perfect match, it plays and works perfectly. The Parts guy at our local chevy place told me that the AM/FM/CD head unit is the same for the 99,20 and 01 models. The AM/FM/Cassette radio that I took out of My 2001 Coupe is for sale cheap if anyone is interested.

99HT

1999 thru 2001 head units are the same part number. The stereo wiring diagram is the same for all years.

Wicked C5

Same POS

Anderson

Thanks everybody for the info.

I'm gonna replace all speakers, add a 10' stealthbox and power it all with 450W. I am keeping the stock head unit however. I don't really care for the current models. I like ***** and a display I can easily read. The stock is just fine.

NastyC5

Anderson the stock deck won't sound good with aftermarket speakers. The stock deck is made for the Bose speakers. I tried this and had to go with an aftermarket deck (Sony) :chevy

99HT

The stock HU sounds fine with aftermarket speakers as long as you add a sub-woofer. The bass control of the Bose HU is set up for a sub-woofer. I modified my Bose HU to change the bass control turnover frequency.

Anderson

99HT,
What exactly did you modify in the Bose HU to change the bass control turnover frequency?

Are the line level preamp outs "conditioned" ? For instance filters out low frequencies. If not, I don't understand what's the problem. The 8" speakers in the doors have to get a signal that contains low freq. Correct me if I am wrong, the 8" get their signals come from the BSP, which in turn comes from the Bose HU preamp outs. If this is the case shouldn't these signals contain low level freq?

Thanks again for the help.

99HT

The pre-amp outputs are unfiltered. Only the Twiddler outputs of the BSP are filtered. The sub outputs of the BSP are not. The sub amps have the crossover built in them.

Look at my post on upgrading a FRC to the Bose HU. The basic info is there. The Bose HU has it's bass turnover frequncy set VERY low, less than 200hz. Normal bass/treble controls are set to "turnover" at about 1khz. I changed four capacitors and two resistors in my Bose HU to make the bass control work like a normal one. The same tone/volume control IC used in the Bose HU is used in many Delco HU's. If you can solder, the upgrade is not too hard. You could even get a repair shop do the mod's.

Anderson

99ht,

I read your info, helped alot. Thanks.
Just one more question, you mentioned in the FRC Bose upgrade post that the bass mod improves the bass enormously. I will have a 10' sub with a 250W amp. Is this mod valid in my scenario? Will it improve the bass with a sub? I am an electrical engineer, so the mod seems doo-able.

Thanks again for your help.

99HT

The main boost is due to the mid range and upper bass frequencies being increased by the modified bass control. I put in 6.75 inch Pioneer 3 way speakers in the doors in my car. These speakers do not have a lot of bass compared to a true sub-woofer.

The standard Bose HU bass control gives very little boost of the upper bass and mid range frequencies. I am used to a normal bass control, not one modified to control sub frequencies only.

If you add a good sub-woofer, you may not need to modify the bass control. I still think it would be nice to control the lower midrange with the bass control like a standard HU would.

Anderson

You sure respond quickly!

If I decided to do this bass mod, where can I find the parts and how do I find out how to get to the Bose HU. I am not the one installing the speakers, amp, sub. I am having a place called Tweeter do it for me. I highly doubt they will do this bass mod. To get to the HU, what needs to be taken apart and how?

Thanks.

99HT

Red my post of the FRC upgrade. The parts are standard 1206 size surface mount components. They are very cheap, but trying to but so few parts is a problem. I would try to talk to a technician friend and show him my instructions.

6SPEEDY

I just installed an amp and sub in my 2002 Coupe per 99HT's instrutions and everything was correct on the C1/2, C3, and C4 connectors.
Dave