C4 Audio FAQ
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C4 Audio FAQ
Please, don't ask questions here! This is a FAQ for comments related to the FAQ, not general questions. Thanks!
I have been thinking of doing this for some time, now. The spirit never quite moved me. However, I got a PM from Shoregasm, which made me create this FAQ page for C4 audio systems.
I culled this together from older threads and relevant links.
First, Shoregasm's tech questions. I am not going to get into component selection, per se, but I will recommend brands to investigate.
This has been edited for content, namely, to get to the brass tacks of the situation, versus the specifics of his PM.
Answer to #1: Wire Diagrams. This site has other diagrams in it for other vintage GM cars.
From 1990 to 1996, the receiver was a stand alone unit. It is connected via a harness to the head unit. Here lies the problem.... I don't think for two straight years GM left it in one place. If you have a 1992, I know for a fact it is in the dash, kinda behind the glove box. Beyond that, it's a crap shoot. The convertibles and certain years, 1993 and 1994, for example, have the module in the ABS bin. It's easier to check the bin than the dash...
Answer to #2: Link is dead.
Answer to #3: The 4 gauge will run nicely down the drivers side sill. there is a channel there that will accept it perfectly. You will have to drill a hole in the fire wall to accept the wire. Fill the hole with RTV after setting in the wire. Run power and ground to the battery.
From fasteddez (this does apply to '94-'96, don't know about '90-'93): As for running a new power wire form the battery...there is a knockout already in the door jam just above the upper hinge that can be utilized, it has a rubber grommet in the existing hole. Using this allows you to avoid molesting your vehicle.
Answer to #4: 84-89: It's in the dash, with the head unit.
90-93: The antenna is rather easy, it is up on the dash, on the receiver, behind and to the center of the glove box. you will need an extension/GM adapter.
94-96: The receiver was relocated due to the addition of the passengers side airbag. It is in the left rear storage bin (behind drivers seat).
Verts are different. The receiver, I think, is in the back. I am not 100% sure.
I am gonna order this up, too... It applies to pre-1993 Vettes.
Thread regarding antenna grounding
Apparently, this part is no longer available. It might be in dealer inventories. I plan on getting one, then will share so others can make their own.
Some tips on C4 Receiver module removal (coupe, 90-93):
These instructions came to me via IM from Shoregasm, thanks! I did some minor editing and such.... but the bulk of this comes from Shoregasm.
1. Remove the air vents under the glove box.
2. Unscrew the underneath cover below the kneepad carpet under the glove box. Pull the carpet corner under the fuse box. It's sort of a press fit. Bend it back.
3. The receiver box which has the antenna lead is silver. The plugs face the fuse box. Two clips top and bottom hold them in two separate harness' come out as one.
4. GM harness is a standard item. You only need the power related one. It includes the power antenna lead, ignition lead, Ground and Battery lead - all in the same harness.
I used the GM harness and then added about 1 1/2 foot of extra wire and ran it under the kneepad carpet and in a hole large enough for the entire aftermarket Sony HU harness (most harnesses are about the same size). Plenty of room in there.
5. Using a long screwdriver, pop out the antenna lead from the silver receiver box. There is one clip in plain site that needs to be popped loose. There is a screw mount holding it closer to the dash. No way to get that one. A short antenna extension and GM adapter will give plenty of reach to the new HU. Done.
If you have a new HU that takes RCA's that plug into the back of it then you will need to trim a piece behind the dash. It will prevent the deck form sliding all the way in. Drill bit will cut a nice fast notch on the right middle side of the plastic. There is a YELLOW box that has a clip. Just pop that off and tuck out of the way. Some head units will have leads that make the actual connection of the RCA's remote from the head unit.
As an aside, a very important aside, anything in the dash that is yellow is related to the airbag. Be VERY careful not to cut, splice, or spindle those wires.
Thoughts regarding the '94-'96 receiver:
The receiver won't have to be removed, just disconnected. The harness on the receiver has all the wiring needed. However, you will need about 5' of wire, in 4 colours - power, ground, memory, antenna. It's best to take the four wires, then bind them at one end, take the other end and insert all wires into a drill and tighten a bit, then let the drill to the work! It will create a nice spun harness which will make running it up the console that much easier.
www.c4guru.com - Head Unit Removal - 1990-1996
Answer to #5: Grounding on a Vette is hard... plastic isn't a good conductor of electricity
. However, many folks have found that the seatbelt bolts work. Personally, I have had great luck with going straight back to the battery. No noise, no questions.
==================================
General Thoughts:
Expect this install to take time; it won't be done in 2 hours. Budget a weekend - or more.
Do you solder? If not, learn! It's the best way to make solid connections that won't come apart. I recommend the Weller SP80 electric iron - super hot. Also, use heat shrink - the good stuff.
I am not a fan of the various adapters out there. Sure, some work, but most of the time they don't, or create more noise than they are worth.
When installing an amp, the bigger the wire, the better. This will require drilling a hole in the firewall, but, that's the price we pay... Refer to the amplifiers manual for wiring guidelines. However, if you are running more than one amp, run at least 4 gauge (2 gauge may better!) to a junction box, and split from there.
Use new wire for speakers, too. I recommend 14 gauge.
Head unit:
I suggest and Eclipse or an Alpine head unit. There are so many available to fit every budget.
A nice, old school system is the Alpine 7939 mated to the Alpine ERA-G320 EQ. eBay only.
Install Kits:
If your C4 is pre-90, Metra and such have nice kits. With 1990+, check with Vrumvrum or Specialty Autosound, Tempe, AZ 85281, 800-937-6644, Part # GM-37, about $20.00 (both kits are metal). Metra now makes a kit for the 1990+, price is about $20.00.
Speakers:
84-89: 6.5" round or even 6x9 can fit in the doors. You will need a "notch" filter, set at 160 Hz, to soften the blow. According to Kale, the door acts like a resonance chamber at the frequency.
90-96: The front's can take 5.25" round components with no problems. However, 6.5" components can be made to fit, with custom enclosures.
Rear: 8" subs, 6.5" round, 6x9. Take your pick.
I suggest Boston Acoustic, CDT, Focal or Rainbow. They all are super smooth. If you can find Canton Pullman Series, get'm. RS1's are 5.25", RS2's are 6.5" (both 2 way separates) and RS3s are 6.5" 3-way. eBay is a good place to check.
If you are creative, I would go with nice 6.5" 2- or 3-way separates up front, and forget rear fill. Something like CDT or Boston.
Subs:
I recommend a single 10", that's what I have it will blow you right outta there! And it can be installed into the storage bin!
10" in storage bin example 1
From this thread....
... Come these pictures
Two 8's is also trick. I like the idea, due to space savings.
nintyfivevette did this and looks fab!
8" Sub Install
For brands, JL Audio, Focal, Eclipse, Kicker, Bramha.
Click Here, here and here for pictures!!!
Amps:
I need to research new brands - Bogus, Aug 2025
Concepts:
Try to keep the tweeter and the woofer together. This will cut down on that sense of separation that occurs when speakers are apart.
I don't recommend bothering with the dash speakers.... Unless you want to build custom crossovers to help overcome the distances.
Repair Options:
The most popular repair location is Dr Don's. He is da man, apparently. And he can convert them over to do MP3s and home burned CDRs.
Dr Don's
Speakers and amps can be serviced at Bose. They are pretty fair on pricing, really. Bose
BadjerJim's Bose Speaker Fix (1990-1996 shown):
Important: Before you do any of this, remove the speakers/enclosures from your Corvette. Yank the Bose speaker enclosures out of the car, and put them on a good work surface, like in the following pics.
Mix Elmer's Carpenters Wood Glue - about 2/3 glue to 1/3 HOT water. HOT water makes it easier and faster to mix,and make for a more uniform stuff to spread. Stir it up good. Here's a pic of about half of a front speaker 'painted' with this mixture:
Next is a pic of the front speaker evenly coated with the glue mixture. Note that it's okay to 'paint' the center Also note that there's some 'run-off' down to the center of the cone. This is normal:
Finally... give it some time... maybe 15 minutes or so. And then 'brush up' the pooled glue near the center of the cone. The idea is: you don't want a big pool of glue-glop near the center of the cone. Brush it up so it looks like this:
For the front speakers in your Bose/Corvette: do not do this to the smaller 'tweeter' speakers. No. Never. Do not. They're already covered by a fine 'mesh' material. Don't be tempted to pull it off and do this glue-treatment to the tweeters.
Rear Speakers
This is very much the same as the front speakers. I've included these pics only because some previous owner (or related 'mechanic') removed the 'kick plate' grill over the front speakers. Bad. So here's some pics of the Rear Speakers, and their related BadjerJim Treatment:
This pic shows the 'kick plate.' Kind of a grill behind the speaker grill:
Remove it so it looks like this, for the treatment:
Brush away with the glue mixture, so the rear speaker ultimately looks like this:
Semi-Important Misc Notes About This Procedure:
1) Realize that the idea here is to 'stiffen' the cone of the speakers. It's okay to get the glue-mixture onto the center (what's known as the 'dust cap') of the speaker.
2) You don't want a big puddle of glue down in the center of the cone. This adds weight/mass. A small puddle, as shown in the pics, is okay.
3) Let the glue-mixture cure and harden in at least room-temperature environs, for at least 24 hours before you test the result. Realize that a big part of this process is letting the hot-water-glue-mixture penetrate the paper of the Bose speaker.
4) Finally... a second coat of the glue-mix probably will not hurt, and may actually help. The overall result will be to make the speakers sound more like Infinity 'poly' speakers. You may or may not like the result. Adding layers of glue will make the speakers sound more 'plasitcy'. Is that a word? Dunno. But for sure: they will be louder and punchier. Don't go beyond 2 coats: that will just weigh down the cones of the speakers, etc.
Cassette Tape Belt Repair: This comes from member, jfb:
GM/Delco Auto sound Cassette Players 1980 thru mid-1990's come in 4 styles.
(1) Non-auto reverse models use 7.4" belt, #1407-161.
(2) Auto reverse Fujitsu 3 Mechanical Button Mechanisms use an 8.6" belt, #1425-07.
(3) Auto reverse Blaupunkt 4-button Mechanisms uses two belts: 4.9" belt, #1407-478 & 9.2" belt #1425-58.
(4) Pioneer (1988 up) and Alpine Mechanisms (1991 up) have electronic switch buttons and use 9.2" belt, #1425-58.
These part numbers are from www.kenselectronics.com, who also sells them.
Stock Delco:
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY. I have been doing some digging - reading the Helms, actually - and I am ready to say - the Delco Bose CD head unit WILL work in place of the stock Delco head. The head feeds data to the receiver module, the receiver either sends data to the speakers, or, to the Bose amps.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.
Bose:
The Bose system came in two flavours, one with and one without a CD. The CD transport is the problem. It does not support CDRs or MP3s. I don't honestly know if MP3s can be done, but modern CD upgrades can pay CDRs.
For 1984-1989, the fronts and rears are 4" within a ported, powered box. The amps are actually inside each speaker enclosure and not centralized.
In the 1990-1996, the speakers are powered boxes, with a 4" and 1.5" tweeter up front, and a 6" round in the rear. Both enclosures are ported. Those ports are tuned to the Bose speaker and will not function with any other speaker. If you reuse the old Bose enclosures, make sure the ports are blocked off.
The amps are weird, they run at 1 ohm. This means that normal speakers cannot be used with those amps.
The advantage to the 1 ohm system is size. The lower the impedance, the more power you get. That amp is supposed to be 50 watts, but in a norm 4 ohm environment, it would only be 12.5 watts. As such, they use an amp which is physically 12.5 watts in size, but produces 50 watts of power. Neat trick.
The main failure of the amps is a capacitor that blows up and spread goo on everything. Replacing the cap will restore function. However, the factory Bose drivers are junk at best. Paper is a great material for speakers, but this is cheap paper, and it dry rots and such. They just don't last.
Compatibility Issues:
These questions come up from time to time.
* 1984-1989 Bose systems are NOT compatible with 1990+ systems.
* C5 and C6 systems are NOT compatible with either version.
* To the best of my knowledge, no other GM Bose system is compatible with the Corvette Bose system, model years 1990+.
* 1984-1989 Bose systems can use other GM Bose heads, mainly, F-Body (and apparently, Monte Carlo!). This requires a couple of adapters to fit the later style GM head unit to the older style chassis connector.
* The reason for this is that the 1984-1989 heads were the Bose processor... 1990+ uses a separate head unit and a stand alone receiver. The receiver is what does all the hard work. This is why a Bose CD head will work with the base Delco system.
Final Comments:
This is a living document. As such, suggestions are welcome!!!
I have been thinking of doing this for some time, now. The spirit never quite moved me. However, I got a PM from Shoregasm, which made me create this FAQ page for C4 audio systems.
I culled this together from older threads and relevant links.
First, Shoregasm's tech questions. I am not going to get into component selection, per se, but I will recommend brands to investigate.
This has been edited for content, namely, to get to the brass tacks of the situation, versus the specifics of his PM.
1) Which wires are the Power, Ground and constant?
2) What needs to be done to remedy the SES light popping on after removal of the stock deck? - Lost to time, August 2025 - Bogus
3) What's the best location to run a 4 Gauge power lead to the hatch area?
4) What am I up against on the antenna lead?
5) Can you suggest a good location for the ground?
2) What needs to be done to remedy the SES light popping on after removal of the stock deck? - Lost to time, August 2025 - Bogus
3) What's the best location to run a 4 Gauge power lead to the hatch area?
4) What am I up against on the antenna lead?
5) Can you suggest a good location for the ground?
From 1990 to 1996, the receiver was a stand alone unit. It is connected via a harness to the head unit. Here lies the problem.... I don't think for two straight years GM left it in one place. If you have a 1992, I know for a fact it is in the dash, kinda behind the glove box. Beyond that, it's a crap shoot. The convertibles and certain years, 1993 and 1994, for example, have the module in the ABS bin. It's easier to check the bin than the dash...
Answer to #2: Link is dead.
Answer to #3: The 4 gauge will run nicely down the drivers side sill. there is a channel there that will accept it perfectly. You will have to drill a hole in the fire wall to accept the wire. Fill the hole with RTV after setting in the wire. Run power and ground to the battery.
From fasteddez (this does apply to '94-'96, don't know about '90-'93): As for running a new power wire form the battery...there is a knockout already in the door jam just above the upper hinge that can be utilized, it has a rubber grommet in the existing hole. Using this allows you to avoid molesting your vehicle.
Answer to #4: 84-89: It's in the dash, with the head unit.
90-93: The antenna is rather easy, it is up on the dash, on the receiver, behind and to the center of the glove box. you will need an extension/GM adapter.
94-96: The receiver was relocated due to the addition of the passengers side airbag. It is in the left rear storage bin (behind drivers seat).
Verts are different. The receiver, I think, is in the back. I am not 100% sure.
I am gonna order this up, too... It applies to pre-1993 Vettes.
Thread regarding antenna grounding
Apparently, this part is no longer available. It might be in dealer inventories. I plan on getting one, then will share so others can make their own.
Some tips on C4 Receiver module removal (coupe, 90-93):
These instructions came to me via IM from Shoregasm, thanks! I did some minor editing and such.... but the bulk of this comes from Shoregasm.
1. Remove the air vents under the glove box.
2. Unscrew the underneath cover below the kneepad carpet under the glove box. Pull the carpet corner under the fuse box. It's sort of a press fit. Bend it back.
3. The receiver box which has the antenna lead is silver. The plugs face the fuse box. Two clips top and bottom hold them in two separate harness' come out as one.
4. GM harness is a standard item. You only need the power related one. It includes the power antenna lead, ignition lead, Ground and Battery lead - all in the same harness.
I used the GM harness and then added about 1 1/2 foot of extra wire and ran it under the kneepad carpet and in a hole large enough for the entire aftermarket Sony HU harness (most harnesses are about the same size). Plenty of room in there.
5. Using a long screwdriver, pop out the antenna lead from the silver receiver box. There is one clip in plain site that needs to be popped loose. There is a screw mount holding it closer to the dash. No way to get that one. A short antenna extension and GM adapter will give plenty of reach to the new HU. Done.
If you have a new HU that takes RCA's that plug into the back of it then you will need to trim a piece behind the dash. It will prevent the deck form sliding all the way in. Drill bit will cut a nice fast notch on the right middle side of the plastic. There is a YELLOW box that has a clip. Just pop that off and tuck out of the way. Some head units will have leads that make the actual connection of the RCA's remote from the head unit.
As an aside, a very important aside, anything in the dash that is yellow is related to the airbag. Be VERY careful not to cut, splice, or spindle those wires.
Thoughts regarding the '94-'96 receiver:
The receiver won't have to be removed, just disconnected. The harness on the receiver has all the wiring needed. However, you will need about 5' of wire, in 4 colours - power, ground, memory, antenna. It's best to take the four wires, then bind them at one end, take the other end and insert all wires into a drill and tighten a bit, then let the drill to the work! It will create a nice spun harness which will make running it up the console that much easier.
www.c4guru.com - Head Unit Removal - 1990-1996
Answer to #5: Grounding on a Vette is hard... plastic isn't a good conductor of electricity
. However, many folks have found that the seatbelt bolts work. Personally, I have had great luck with going straight back to the battery. No noise, no questions.==================================
General Thoughts:
Expect this install to take time; it won't be done in 2 hours. Budget a weekend - or more.
Do you solder? If not, learn! It's the best way to make solid connections that won't come apart. I recommend the Weller SP80 electric iron - super hot. Also, use heat shrink - the good stuff.
I am not a fan of the various adapters out there. Sure, some work, but most of the time they don't, or create more noise than they are worth.
When installing an amp, the bigger the wire, the better. This will require drilling a hole in the firewall, but, that's the price we pay... Refer to the amplifiers manual for wiring guidelines. However, if you are running more than one amp, run at least 4 gauge (2 gauge may better!) to a junction box, and split from there.
Use new wire for speakers, too. I recommend 14 gauge.
Head unit:
I suggest and Eclipse or an Alpine head unit. There are so many available to fit every budget.
A nice, old school system is the Alpine 7939 mated to the Alpine ERA-G320 EQ. eBay only.
Install Kits:
If your C4 is pre-90, Metra and such have nice kits. With 1990+, check with Vrumvrum or Specialty Autosound, Tempe, AZ 85281, 800-937-6644, Part # GM-37, about $20.00 (both kits are metal). Metra now makes a kit for the 1990+, price is about $20.00.
Speakers:
84-89: 6.5" round or even 6x9 can fit in the doors. You will need a "notch" filter, set at 160 Hz, to soften the blow. According to Kale, the door acts like a resonance chamber at the frequency.
90-96: The front's can take 5.25" round components with no problems. However, 6.5" components can be made to fit, with custom enclosures.
Rear: 8" subs, 6.5" round, 6x9. Take your pick.
I suggest Boston Acoustic, CDT, Focal or Rainbow. They all are super smooth. If you can find Canton Pullman Series, get'm. RS1's are 5.25", RS2's are 6.5" (both 2 way separates) and RS3s are 6.5" 3-way. eBay is a good place to check.
If you are creative, I would go with nice 6.5" 2- or 3-way separates up front, and forget rear fill. Something like CDT or Boston.
Subs:
I recommend a single 10", that's what I have it will blow you right outta there! And it can be installed into the storage bin!
10" in storage bin example 1
From this thread....
... Come these pictures
Two 8's is also trick. I like the idea, due to space savings.
nintyfivevette did this and looks fab!
8" Sub Install
For brands, JL Audio, Focal, Eclipse, Kicker, Bramha.
Click Here, here and here for pictures!!!
Amps:
I need to research new brands - Bogus, Aug 2025
Concepts:
Try to keep the tweeter and the woofer together. This will cut down on that sense of separation that occurs when speakers are apart.
I don't recommend bothering with the dash speakers.... Unless you want to build custom crossovers to help overcome the distances.
Repair Options:
The most popular repair location is Dr Don's. He is da man, apparently. And he can convert them over to do MP3s and home burned CDRs.
Dr Don's
Speakers and amps can be serviced at Bose. They are pretty fair on pricing, really. Bose
BadjerJim's Bose Speaker Fix (1990-1996 shown):
Important: Before you do any of this, remove the speakers/enclosures from your Corvette. Yank the Bose speaker enclosures out of the car, and put them on a good work surface, like in the following pics.
Mix Elmer's Carpenters Wood Glue - about 2/3 glue to 1/3 HOT water. HOT water makes it easier and faster to mix,and make for a more uniform stuff to spread. Stir it up good. Here's a pic of about half of a front speaker 'painted' with this mixture:
Next is a pic of the front speaker evenly coated with the glue mixture. Note that it's okay to 'paint' the center Also note that there's some 'run-off' down to the center of the cone. This is normal:
Finally... give it some time... maybe 15 minutes or so. And then 'brush up' the pooled glue near the center of the cone. The idea is: you don't want a big pool of glue-glop near the center of the cone. Brush it up so it looks like this:
For the front speakers in your Bose/Corvette: do not do this to the smaller 'tweeter' speakers. No. Never. Do not. They're already covered by a fine 'mesh' material. Don't be tempted to pull it off and do this glue-treatment to the tweeters.
Rear Speakers
This is very much the same as the front speakers. I've included these pics only because some previous owner (or related 'mechanic') removed the 'kick plate' grill over the front speakers. Bad. So here's some pics of the Rear Speakers, and their related BadjerJim Treatment:
This pic shows the 'kick plate.' Kind of a grill behind the speaker grill:
Remove it so it looks like this, for the treatment:
Brush away with the glue mixture, so the rear speaker ultimately looks like this:
Semi-Important Misc Notes About This Procedure:
1) Realize that the idea here is to 'stiffen' the cone of the speakers. It's okay to get the glue-mixture onto the center (what's known as the 'dust cap') of the speaker.
2) You don't want a big puddle of glue down in the center of the cone. This adds weight/mass. A small puddle, as shown in the pics, is okay.
3) Let the glue-mixture cure and harden in at least room-temperature environs, for at least 24 hours before you test the result. Realize that a big part of this process is letting the hot-water-glue-mixture penetrate the paper of the Bose speaker.
4) Finally... a second coat of the glue-mix probably will not hurt, and may actually help. The overall result will be to make the speakers sound more like Infinity 'poly' speakers. You may or may not like the result. Adding layers of glue will make the speakers sound more 'plasitcy'. Is that a word? Dunno. But for sure: they will be louder and punchier. Don't go beyond 2 coats: that will just weigh down the cones of the speakers, etc.
Cassette Tape Belt Repair: This comes from member, jfb:
GM/Delco Auto sound Cassette Players 1980 thru mid-1990's come in 4 styles.
(1) Non-auto reverse models use 7.4" belt, #1407-161.
(2) Auto reverse Fujitsu 3 Mechanical Button Mechanisms use an 8.6" belt, #1425-07.
(3) Auto reverse Blaupunkt 4-button Mechanisms uses two belts: 4.9" belt, #1407-478 & 9.2" belt #1425-58.
(4) Pioneer (1988 up) and Alpine Mechanisms (1991 up) have electronic switch buttons and use 9.2" belt, #1425-58.
These part numbers are from www.kenselectronics.com, who also sells them.
Stock Delco:
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY. I have been doing some digging - reading the Helms, actually - and I am ready to say - the Delco Bose CD head unit WILL work in place of the stock Delco head. The head feeds data to the receiver module, the receiver either sends data to the speakers, or, to the Bose amps.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.
Bose:
The Bose system came in two flavours, one with and one without a CD. The CD transport is the problem. It does not support CDRs or MP3s. I don't honestly know if MP3s can be done, but modern CD upgrades can pay CDRs.
For 1984-1989, the fronts and rears are 4" within a ported, powered box. The amps are actually inside each speaker enclosure and not centralized.
In the 1990-1996, the speakers are powered boxes, with a 4" and 1.5" tweeter up front, and a 6" round in the rear. Both enclosures are ported. Those ports are tuned to the Bose speaker and will not function with any other speaker. If you reuse the old Bose enclosures, make sure the ports are blocked off.
The amps are weird, they run at 1 ohm. This means that normal speakers cannot be used with those amps.
The advantage to the 1 ohm system is size. The lower the impedance, the more power you get. That amp is supposed to be 50 watts, but in a norm 4 ohm environment, it would only be 12.5 watts. As such, they use an amp which is physically 12.5 watts in size, but produces 50 watts of power. Neat trick.
The main failure of the amps is a capacitor that blows up and spread goo on everything. Replacing the cap will restore function. However, the factory Bose drivers are junk at best. Paper is a great material for speakers, but this is cheap paper, and it dry rots and such. They just don't last.
Compatibility Issues:
These questions come up from time to time.
* 1984-1989 Bose systems are NOT compatible with 1990+ systems.
* C5 and C6 systems are NOT compatible with either version.
* To the best of my knowledge, no other GM Bose system is compatible with the Corvette Bose system, model years 1990+.
* 1984-1989 Bose systems can use other GM Bose heads, mainly, F-Body (and apparently, Monte Carlo!). This requires a couple of adapters to fit the later style GM head unit to the older style chassis connector.
* The reason for this is that the 1984-1989 heads were the Bose processor... 1990+ uses a separate head unit and a stand alone receiver. The receiver is what does all the hard work. This is why a Bose CD head will work with the base Delco system.
Final Comments:
This is a living document. As such, suggestions are welcome!!!
Last edited by bogus; Aug 2, 2025 at 08:47 PM. Reason: that guy doesn't do this anymore
Safety Car
Joined: Sep 2004
Posts: 4,815
Likes: 0
From: Port Orange Florida
Luvs It!! 
I am on a budget...I do know stereo installs....BUT there is a limit to what I will tackle.The BLOSE was the limit...Until I figured a way around re-wiring the car.
2 amps!!!!!!
Super simple...1 amp for the mids and highs and one for the sub...The H*** with the Bose system.Throw it away...all of it.You would not believe the smell I had from a burnt Bose amp.It wasn't recent either.
I have ideas runnin through my head more and more...and this car is gonna slam!
Thx To Bogus for actually takin the time to care about something.It's this kinda stuff that gets ya movin in the right direction.
I am on a budget...I do know stereo installs....BUT there is a limit to what I will tackle.The BLOSE was the limit...Until I figured a way around re-wiring the car.
2 amps!!!!!!
Super simple...1 amp for the mids and highs and one for the sub...The H*** with the Bose system.Throw it away...all of it.You would not believe the smell I had from a burnt Bose amp.It wasn't recent either. I have ideas runnin through my head more and more...and this car is gonna slam!
Thx To Bogus for actually takin the time to care about something.It's this kinda stuff that gets ya movin in the right direction.
Instructor
Joined: Aug 2004
Posts: 113
Likes: 0
Good post dude. I am still contemplating between a single 10" in the compartment and a pair of 8's in the 6x9 holes. There are also some 6x9 subs that will drop right in and apparently hammer that I am also looking at.
Pro
Joined: Dec 2002
Posts: 695
Likes: 1
From: Edgewood WA
Originally Posted by DF
Something I have thought about but never suggested or tried to tackle.
I am pretty certain that VrumVrum has dash kits for pre 90.
I heard he built a couple of adapter blocks to fit the C5 mount in a pre 90. He'd probably just have to use the C4 engraving style. There was never much demand so I heard he didn't make a lot of them.
Le Mans Master
Joined: Jul 2004
Posts: 7,163
Likes: 61
From: NH
St. Jude Donor '14
Couple of comments... - I have my system already done in my Vette, just waiting for money before I order the DVD screen. I have rear fill, and they really do make a difference. I'm running CDT 6.5" components up front, and MB Quart 6.5" drivers in the rear. I origionally wasn't going to, but I also have a 12" E12O from eD, and without the rear drivers, you'd barely hear mids. Depending on your system, sub and box volume-vs-recommended range, I would recommend rear drivers in certain applications.
Also... You put CTD further up. ; )
-Joe
Also... You put CTD further up. ; )
-Joe
Drifting
Joined: Feb 2004
Posts: 1,485
Likes: 2
From: Champaign, IL
St. Jude Donor '05
I didn't even know C4 audio FAQ existed I had to run a search to find this post! Move this to C4 tech and make it a sticky there for people like me that can't navigate the site competently.
I called Dr. Don's yesterday and talked to Don. He said he would give Corvette Forum members a discount on CD player repairs. This usually runs $150 and comes with a year warranty but he said for forum members he would give a $20 discount and rebuild the cd players for $130. My cd player is in the mail I just thought I'd give everyone a heads up on this!
I called Dr. Don's yesterday and talked to Don. He said he would give Corvette Forum members a discount on CD player repairs. This usually runs $150 and comes with a year warranty but he said for forum members he would give a $20 discount and rebuild the cd players for $130. My cd player is in the mail I just thought I'd give everyone a heads up on this!
Racer
Joined: Sep 2004
Posts: 430
Likes: 2
From: Sellersville, PA
St. Jude Donor '10
Stock Delco:
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY and will not support a Bose head. The harness ain't there.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY and will not support a Bose head. The harness ain't there.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.
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Team Owner
Joined: Apr 2002
Posts: 28,741
Likes: 41
From: Frankenstein never scared me. Marsupials do, because they're fassst…and they DART, THAT'S crazy!
St. Jude Donor '03 thru '26
Originally Posted by bogus
Bose:
For 1984-1989, the fronts are 4" within a box and 6x9s in the rear (if I remember rightly).
For 1984-1989, the fronts are 4" within a box and 6x9s in the rear (if I remember rightly).
In fact, you already have a link to a picture of this plastic mounting ring in this thread. This thing holds and mounts the rear Bose pod. As you can see, with the pod removed from it, there is a place to mount a 6x9.This was used with both the Bose and non-Bose systems. In the non-Bose systems it held a really crappy 6x9. In the Bose systems it held the Bose pod with a really crappy 4" speaker in it.
Instructor
Joined: Aug 2002
Posts: 120
Likes: 1
From: ohio
Just a few small notes...
1. The reciever box in 94 and later is behind the passenger seat in the rear glove box next to the jack...you will need to run your wires from there to your new head unit.
2. As for running a new power wire form the battery...there is a knockout already in the door jam just above the upper hinge that can be utilized, it has a rubber grommet in the existing hole. Using this allows you not to molest your vehicle.
1. The reciever box in 94 and later is behind the passenger seat in the rear glove box next to the jack...you will need to run your wires from there to your new head unit.
2. As for running a new power wire form the battery...there is a knockout already in the door jam just above the upper hinge that can be utilized, it has a rubber grommet in the existing hole. Using this allows you not to molest your vehicle.
Melting Slicks
Joined: Aug 1999
Posts: 2,619
Likes: 1
From: Whidbey Island Washington
Need help selecting Bose replacement for '90
Our Bose system is history and we do not want to spend any $$ on it.
What is best inexpensive aftermarket buy for an AM-FM CD, and /or Cassett tape stereo system including speakers, antenna raise-lowering and wiring that will completely replace ALL the BOSE junk and not screw up any remaining C4 coupe's options...sport seats, alarms etc. We've heard too many horror stories about stereo shops butchering the operation and looks of the C4 interior trying to force fit some after market system. Really afraid to make the change, but it's long overdue. Anyone in the Seattle area that knows of a stereo dealer that we could trust to make the change? Thanks in advance for the help. Bill
What is best inexpensive aftermarket buy for an AM-FM CD, and /or Cassett tape stereo system including speakers, antenna raise-lowering and wiring that will completely replace ALL the BOSE junk and not screw up any remaining C4 coupe's options...sport seats, alarms etc. We've heard too many horror stories about stereo shops butchering the operation and looks of the C4 interior trying to force fit some after market system. Really afraid to make the change, but it's long overdue. Anyone in the Seattle area that knows of a stereo dealer that we could trust to make the change? Thanks in advance for the help. Bill
Intermediate
Joined: May 2004
Posts: 46
Likes: 0
From: Huntsville AL
Im gonna have to disagree on something in the post. Even if the sub is in front of the rearfill, it is still a good idea to have the added rear speakers. Although you will barely hear them, they will not be completely inaudible unless you just have your bass turned all the way up and enjoy ground pounding. A nice set of 3 way 6x9's work and sound nicely.
excellent write up though. A+
excellent write up though. A+
Race Director
Joined: Nov 2002
Posts: 14,298
Likes: 3
From: S. Florida
Well I have several questions not yet answered in this thread(I think).
I have a 1990 ZR-1 and at least two or more speakers are out. I've heard that my speakers amps are 50 watts being a coupe/targa, where as the convertibles are 75 watts. So my first question is it true?
If so, can I install the 75watt amps with my system without any problem? If so, how can I get my hands on 4 used amps out of a convertible? Obviously if they all work problem solved, but if not I can send them off to Dr Don's or Blose to get them fixed.
The next question would be regarding year to year compatibility. Which other year Corvette amps will fit/work with my 1990 speakers?
TIA
I have a 1990 ZR-1 and at least two or more speakers are out. I've heard that my speakers amps are 50 watts being a coupe/targa, where as the convertibles are 75 watts. So my first question is it true?
If so, can I install the 75watt amps with my system without any problem? If so, how can I get my hands on 4 used amps out of a convertible? Obviously if they all work problem solved, but if not I can send them off to Dr Don's or Blose to get them fixed.
The next question would be regarding year to year compatibility. Which other year Corvette amps will fit/work with my 1990 speakers?
TIA
Race Director
Joined: Nov 2002
Posts: 14,298
Likes: 3
From: S. Florida
Originally Posted by bogus
Another option is sending your existing Bose speakers back to bose. I think they charge about $75.00 each to install new amps and drivers. The systems are also updated to the latest, greatest spec.
I came across these aftermarket amps being sold on ebay
http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWA%3AIT
Any thoughts or experience with them?
1st Gear
Joined: Apr 2005
Posts: 1
Likes: 0
Delco Bose head unit
For 1995, the stock Delco head unit is plug 'n play replaceable with the Delco Bose head unit. I've done it.
My questions are as follows: Does the stock receiver need to be replaced with a Bose receiver to be compatible with the amplified Bose speakers? Or will the stock receiver work directly with the amplified Bose speakers? Do the speaker cables need to be replaced in either case? If I do need a Bose receiver and/or cables, where can I find them for sale?
[Stock Delco:
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY. I have been doing some digging - reading the Helms, actually - and I am ready to say - the Delco Bose CD head unit might just work in place of the stock Delco head. The head feeds data to the reciever module, the reciever either sends data to the speakers, or, to the Bose amps. Think about it.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.]
My questions are as follows: Does the stock receiver need to be replaced with a Bose receiver to be compatible with the amplified Bose speakers? Or will the stock receiver work directly with the amplified Bose speakers? Do the speaker cables need to be replaced in either case? If I do need a Bose receiver and/or cables, where can I find them for sale?
[Stock Delco:
This is not a system that will cause your heart to stop in pure sound quality, but it does hold up better than the Bose system!
The stock system uses no external amps, has a cassette player ONLY. I have been doing some digging - reading the Helms, actually - and I am ready to say - the Delco Bose CD head unit might just work in place of the stock Delco head. The head feeds data to the reciever module, the reciever either sends data to the speakers, or, to the Bose amps. Think about it.
The speakers are 5x7 in the front and 6x9 in the back.
You can update this system in stages. Head unit, speakers, whatever. The impedance isn't an issue here.]
Pro
Joined: Aug 2005
Posts: 656
Likes: 0
From: Fort Worth TX
OK lets clarify where the connectors that hook up to your aftermarket harness are. They are located just slightly down and to the right of the fuse box on the radio reciver. The reciver has 4 harnesses pluged into it, two on the side by the fuse box and two on the other. You want the two on the fuse box side. I spent way to long and about broke my hand trying to get to the other ones only to find out they weren't what I needed.
Last edited by RFDrpm; May 4, 2006 at 10:32 AM.
Race Director
Joined: Jul 1999
Posts: 16,282
Likes: 104
From: Sun city CA
Clarion & Infinities
Installed DXZ845MC Clarion and Infinity reference speakers...
Already had this completed in my 91... It sounds great now that my friend helped me ( he also has the Clarion and Infinity setup ) fix the screwed up Circuit City install... Not trying to bash Bose, but their is little to compare in terms of sound quality. What would you expect with gear that is engineered 10 to 15 years later ?
Doing the 89 Coupe now... Glad we have this forum because stuff is a little different... a real learning experience for sure... My point in writing this is simple... for less than $500 and weekend of your time you can have a great stereo. Many of you guys want more than what I have... and I understand the need to really kick out the bass, but my ears can't take it anymore !
Regardless, that Clarion with "music catcher" ( records about 80 songs from CDs and stores them ) and infinatly adjustible backlighting to match your dash lighting is simply awesome !
Already had this completed in my 91... It sounds great now that my friend helped me ( he also has the Clarion and Infinity setup ) fix the screwed up Circuit City install... Not trying to bash Bose, but their is little to compare in terms of sound quality. What would you expect with gear that is engineered 10 to 15 years later ?
Doing the 89 Coupe now... Glad we have this forum because stuff is a little different... a real learning experience for sure... My point in writing this is simple... for less than $500 and weekend of your time you can have a great stereo. Many of you guys want more than what I have... and I understand the need to really kick out the bass, but my ears can't take it anymore !
Regardless, that Clarion with "music catcher" ( records about 80 songs from CDs and stores them ) and infinatly adjustible backlighting to match your dash lighting is simply awesome !