I have a idea for the factory Radio woes, I need advise from radio experts

[Skant]

I went for the full replacement with aftermarket. It was expensive, but the results are nothing less than spectacular.

My system consists of:

- Sony CDX-MP70 Xplod CD/MP3 Head unit
- Sony 6.5" Xplod speakers (All four, front and back)
- Sony 760watt Xplod Amplifier
- 2x10" Sony Xplod Subwoofers
- Custom made Subwoofer box

Notes:

- The rear speaker grills look like they'd house 6x9's, but they don't. They take 6.5". The original Bose grills are still in place even though it's not Bose underneath.

- Normally, the front speakers would need to be replaced by 5.5". However, the stereo installer I went to was able to fashion housings for 6.5" and fit into them. Doing this pushed the speaker covers out slightly.. maybe a half an inch of leg space lost around the speaker housing. No biggie.

- The subwoofer setup takes up about half the cargo space in my vette. The custom box was specifically sized to take up the aft section. It's the perfect size for dual 10" woofers. The box has quick linkages and can be removed to restore my cargo capacity (ha ha.. cargo capacity in a vette... yeah right...).

- The pull screen clears the custom subwoofer box. The targa top will still fit in the back with the subwoofer box in place.

- The glass targa top amplifies the bass like crazy when it is stowed in the back over the subwoofer. I have to adjust the equalizer settings in a big way to level it out.

- The amplifier is mounted on top of the lid over the left side cubby (where the ASR is located). A custom carpet covered box is placed over it. So while it does take up a little of the cargo space, it just effectively raises the floor a few inches on one side. I can still put stuff on top of it and use it as a floor.

- The dual 10" subwoofers turned out to be a complete overkill. The hatchback design and small interior space make the vette an extremely efficient bass chamber. A small nominally undersized subwoofer would have sufficed. My subwoofer volume knob is turned way way down, and still makes my hair compress against the back of my head when the music is thumping. Still, the overkill does mean the bass response is very tight and clean.

- Subwoofers designed to fit in the right rear cubby (ie. no cargo loss) are available. You lose your tire changing kit.

- The CDX-MP70 has a tray which extends out the front to load CDs. I can not shift into 1st, 3rd, or 5th while the tray is extended. This is not normally a problem since an MP3 CD holds about 10 hours of music. Changing discs is rare.

- My sub woofers did not originally have grills. I added them after realizing that cargo placed in the back would get shoved back into the woofer cones when I put my foot into the gas.

- Installing the system required substantial rewiring all over the vette. The rear box from your original Bose system (the amp thing that sits in the right cubby) must stay. It performs other functions for the car and is plugged into various wiring harnesses.

- Some resistors and such have to be installed to fool the ECM into believing the original stereo is still installed so it doesn't throw a code and flash a warning light.

- Seek a professional stereo installer who has experience with Vettes (not Circuit City). There are a lot of special requirements and connections between stereo components and the running gear for the car. Ask them to show you pictures of their previous Vette installs. They will have them. They all take pictures.


My system... complete and installed... cost me about $1500 and took them two full days of work. About $300 of that was installation labor.

It was absolutely worth it.


Probably more information than you wanted. But maybe something in this post will help! I thought the niggly details and limitations you usually don't learn until _after_ the install might be of use.

- Skant

 

[hawker4611]

Reggie,
I liked your Idea and hoped it would go somewhere!!! I have a '90 with just squeal from the right rear...In my research, I find that FCSR is the best and most reliable repair people, lifetime garranty! But add it up, Each speaker is $80, CDM $140 and Head $140.

So it's still worth watching what you are trying to do in hopes you succeed. I have squeal at rt rear speaker only, so chances are, its the CDM. Get that repaired and then I can check the speakers for their operation.

Anybody have a shortcut to check the speakers?

Watching your progress Reggie

 

[air1jpg]

Stock system
- It's the original equipment for matching numbers folks
- It's smaller than an equivalent aftermarket setup (because it produces subwoofer like bass without a subwoofer)
- It has serious reliability issues
- It's sound quality is not up to modern standards
- No modern abilities like mp3 play, multi-disk, etc

If you decide to repair the original system, you can use a mp3 player, ipod, or a sat. radio by using one of those old cd to cassette adapters people used to use when the portable cd players came out.

 

[Curious George]

Stock system
- It's the original equipment for matching numbers folks
- It's smaller than an equivalent aftermarket setup (because it produces subwoofer like bass without a subwoofer)
- It has serious reliability issues
- It's sound quality is not up to modern standards
- No modern abilities like mp3 play, multi-disk, etc

If you decide to repair the original system, you can use a mp3 player, ipod, or a sat. radio by using one of those old cd to cassette adapters people used to use when the portable cd players came out.

This thread is 6+ years old. I doubt Reggie is still following this post... :L

I can tell you from experience though that it is possible to interface with the factory Bose system and not cause any problems with good sound quality. I have done it. I have a '92 that I removed the OE head unit and replaced it with a 2DIN multimedia head unit w/ 6.5" TFT screen.

I did however have to make an adapter to interface the front / rear pre-amp outputs to the Bose amp inputs. No pops, clicks, thumps or noise of any kind. You can make they adapter for about $30 or buy one already made from companies like Peripheral or Scosche.

I have worked in the mobile audio industry since 1983. I usually tried to avoid letting anybody know this on forums because you will just get badgered by somebody who installed one car stereo when they were 13 and they know it all.

I'll dig up a schematic of my adapter and post it.

Edit: The transformers in the schematic are from "ground loop isolators". Many companies make these under various brand names. The Radio Shack ones use fairly decent transformers. You can find the isolators at Radio Shack, Walmart (car audio department), Best Buy, Fry's, etc.

When you buy the isolator, you will have to disassemble it and take out the transformers. I used a small project box from Radio Shack (RS) to assemble the home brew adapter in. You can elect to use old male RCA ends (flying leads) to go into your adapter from your aftermarket head unit, to your project box, or use chassis mount female RCA's (I used chassis mount RCA's). The wires coming out of the adapter to go to the Bose wire harness can be simply speaker wires (make sure you label the wires for easy identification).

Circuit Analysis: The transformers physically isolate the head unit from the Bose amp input circuitry. This is necessary because the Bose amp input circuitry is unconventional and has a DC-offset present. The transformers also provide isolation from any "ground loops" that may form when multiple devices are connected that share a common ground (the chassis of the vehicle). The capacitors block "most" of the DC-offset from the amp input circuitry which might saturate the transformer core. The resistors are there to shunt any DC-offset to ground, that may leak through the caps, and to provide a path to ground, for the input as well.


CG

 

[Newfydad]

>>I'll dig up a schematic of my adapter and post it.

Please do.
Thanks.

 

[Curious George]

This thread is 6+ years old. I doubt Reggie is still following this post... :L

I can tell you from experience though that it is possible to interface with the factory Bose system and not cause any problems with good sound quality. I have done it. I have a '92 that I removed the OE head unit and replaced it with a 2DIN multimedia head unit w/ 6.5" TFT screen.

I did however have to make an adapter to interface the front / rear pre-amp outputs to the Bose amp inputs. No pops, clicks, thumps or noise of any kind. You can make they adapter for about $30 or buy one already made from companies like Peripheral or Scosche.

I have worked in the mobile audio industry since 1983. I usually tried to avoid letting anybody know this on forums because you will just get badgered by somebody who installed one car stereo when they were 13 and they know it all.

I'll dig up a schematic of my adapter and post it.

Edit: The transformers in the schematic are from "ground loop isolators". Many companies make these under various brand names. The Radio Shack ones use fairly decent transformers. You can find the isolators at Radio Shack, Walmart (car audio department), Best Buy, Fry's, etc.

When you buy the isolator, you will have to disassemble it and take out the transformers. I used a small project box from Radio Shack (RS) to assemble the home brew adapter in. You can elect to use old male RCA ends (flying leads) to go into your adapter from your aftermarket head unit, to your project box, or use chassis mount female RCA's (I used chassis mount RCA's). The wires coming out of the adapter to go to the Bose wire harness can be simply speaker wires (make sure you label the wires for easy identification).

Circuit Analysis: The transformers physically isolate the head unit from the Bose amp input circuitry. This is necessary because the Bose amp input circuitry is unconventional and has a DC-offset present. The transformers also provide isolation from any "ground loops" that may form when multiple devices are connected that share a common ground (the chassis of the vehicle). The capacitors block "most" of the DC-offset from the amp input circuitry which might saturate the transformer core. The resistors are there to shunt any DC-offset to ground, that may leak through the caps, and to provide a path to ground, for the input as well.


CG

Here it is.

CG

 

[Newfydad]

I sense another winter project coming up.
Thank you
Rod.

 

[CorvetteArchives]

This is a most interesting thread with a reasoned debate. Very refreshing! Interested in the final outcome even if its 6 years later!.

The weak link in the stock systems is the whole system!

I think you hit the nail on the head with that statement!

The stock system is great for people that like to hear something better than what they hear in their stock pick up truck, passenger car, etc.

Its odd though....the stock system in my plain jane Honda Element sounds WAY better than the Bose EVER did! :confused I rememember Dr Bose on This Old House once, and a couple times on TV elsewhere and every time he was an ARROGANT _____ ! If I ever met him (is he dead?) I'd start calling him Dr Base and then say ...oh thats right...you dont believe in ANY decent base do you?

 

[Curious George]

Bose - better research through marketing. Usually, anybody who is into music (home audiophile) will not have Bose equipment. I know this is a very broad statement, but it is usually true. Bose does not publish specifications of any kind, and if they do, they are so general they are useless.

The Bose system in the '92 convertible is not too bad, but definitely needs some help. If the OE head unit is replaced with a decent aftermarket head unit this is a step in the right direction. The next limitation is the front speakers... when you are sitting in the front seats, your legs are covering up the tweeters in the front speaker enclosures. If there are two people in the car, you literally have no high frequency extension. If the driver is the only person in the car, then you have a lot of high frquencies from the passenger side of the car and none from the driver side. This is a very annoying situation. In addition, the tweeters in the front speaker enclosures are crummy two inch paper tweeters from the 70's. Who hoo...

I did not necessarily want to extensively modify the Bose system nor take it out completely. So I carefully evaluated its deficiencies. I thought about where I could relocate the tweeters to, to provide better high frequency extension. I had some 19mm cloth dome home audio tweeters that had no front bezel on them w/ a neodymium magnet. They were very small and could be placed almost anywhere. I ended up disconnecting the OE tweeters and running wires out of the front speaker enclosures up to the driver and passenger side a/c vents. I placed a tweeter in each vent. This was popular back in the late 80's and early 90's in the car audio world. I still have some air flow through each vent, but not as much as if nothing was there. Each vent is still usable though. I played around with different speaker levels and crossover points until I reached what I thought was a good compromise.

Now, when I sit in the car with or without passengers, I can enjoy full range sound and not worry about my legs covering up the tweeters. The system actually sounds quite good in this configuration. You would not believe it unless you heard it. The first thing people say is to tear out all that Bose junk, but with a little work, it can actually be turned into a very respectable system. I guess you just need to know how to evaluate it and make the necessary adjustments.

CG