Carver DSP + Aftermarket Audio: The essential info you need

[OneFastMac]

I recently had an adventure with my Z4's aftermarket audio and I learned that my car was originally equipped with the Carver DSP "Top HiFi" Premium Audio system. I bought the car with aftermarket equipment already installed, but none of it worked properly and I had to dig and scrape and hunt for this information I'm about to share. Some of it was here. Some of it was on Z4-Forum, Some of the posts no longer had photos, some of the posts had vague information or missing details, some of it was on a private website where the information was detailed, but scattered and hard to parse (also a little too much gun propaganda, but that's neither here nor there)

So without any further adieu, I hereby present, in one single location, all the basic information needed for the next fool that buys an E85 Z4 with a butchered DSP system. :P

The BMW Business CD radio on the DSP system only provides Channel 1 (Front Left) and Channel 2 (Front Right) audio signals to the OEM amplifier where the signals are summed, and the processed audio signals are sent to each individual speaker, including the Carver subwoofers. The radio and DSP amp are connected by the K bus which is a digital signal specific to the vehicle's built-in systems.


What that means:
-You can’t use an aftermarket amp with the stock radio.
-You can’t use an aftermarket radio with the stock amp.
-You can’t use the Carver subwoofers without the stock amp.
-You can’t use the built-in bluetooth phone features without the stock radio.
-You’re gonna be so mad if you bought a Z4 with a non-functioning DSP system.

What you can do about it:
-You CAN install an aftermarket radio with an aftermarket amplifier using the stock wiring harness.
-You CAN replace the Carver subwoofers (that procedure is not covered here, but you can do it I believe in you. It may be worth it to just buy the standard woofers from the non-DSP system. They'll fit in the same place and they're just standard paper 2ohm woofers, like $50 on ebay)
-You CAN enjoy great sound from all ten speakers with most any aftermarket analog amp or DSP amp.

This shows the pin blocks at the OEM radio harness. You’ll only be using the following pins from block A. Wire colors are for the OEM "Top HiFi" wiring which will come in handy when wiring up signal inputs at the amp. Your radio harness adapter will have different colors and probably include some wires that you will not need to connect to anything because of reasons.

2 - Front Right Positive — Blue w/Red
7 - Front Right Negative — Brown w/Orange
3 - Front Left Positive — Yellow w/Red
8 - Front Left Negative — Brown w/Orange
12 - Ground wire — Brown
13 - Amp Remote Power — White
15 - 12v Power — Red w/Yellow
16 - Radio Remote Power — Violet w/White

(When wiring in power for the amp, the white #13 wire is your remote turn-on signal. You can find it in the factory amp wiring harness.)

You’ll be tempted to connect ALL the wires on your radio harness adapter but I assure you, you only need the 8 connections listed above. Since the OEM radio is connected to the K-Bus, signals from other wires won’t be interpreted by your aftermarket system and may cause numerous issues with system operation including but not limited to: Amp always on, dead battery now, panic because you thought you knew what you were doing, you idiot.

In my case, I had a 4 channel amp and if you paid attention up to this point, you understand that there are only 2 channels of audio coming from the OEM radio harness.
Because of that, I wanted to send full range frequencies to the tweeters and mid-range speakers and low range frequencies to the front woofers and rear subwoofers.

How I achieved this is by connecting the factory Ch1 and Ch2 wiring to the corresponding hi-level inputs on the amp and splicing channels 3 & 4 into Ch1 and Ch2. This way, the same signals are being fed to all four corresponding channels on the amp, but I used the low-pass filter just on Ch3 & Ch4. I wired speaker-out channels 1 & 2 to the six high and mid frequency speakers and I wired speaker-out channels 3 & 4 to the front and rear low frequency woofers.

This is where it can get a little overwhelming because of just how many wires there are on the amp harness. The guide above will tell you which wires to use for your amp inputs and the guide below will tell you which wires to use for your speaker outputs.

Speaker locations and wire colors:
LEFT SPEAKERS
- Tweeter Positive — Yellow w/Red
- Tweeter Negative — Yellow w/Brown

- Front Door Positive — Blue w/White
- Front Door Negative — Blue w/Brown

- Front Kick Woofer Positive — Red w/Yellow
- Front Kick Woofer Negative — Red w/Brown

- Rear Upper Positive — Yellow w/Black
- Rear Upper Negative — Yellow w/Brown

- Rear Lower (Subwoofer) Positive — Yellow
- Rear Lower (Subwoofer) Negative — Brown

RIGHT SPEAKERS
- Tweeter Positive — Blue w/Black
- Tweeter Negative — Blue w/Brown

- Front Door Positive — Blue w/Red
- Front Door Negative — Blue w/Brown

- Front Woofer Positive — Blue w/White
- Front Woofer Negative — Blue w/Brown

- Rear Upper Positive — White w/Black
- Rear Upper Negative — White w/Brown

- Rear Lower (Subwoofer) Positive — Blue
- Rear Lower (Subwoofer) Negative — Brown

This is all the info you need to have to successfully wire up an aftermarket radio with an aftermarket amp in your Top HiFi “Premium Audio” CarverTM BMW E85 Z4. Your mileage may vary, but all the essential info you need should be listed above. Happy soldering!

[cotton90]

That's pretty awesome info! Thanks for compiling and posting!

[Piper1]

Not knowing much about wiring in car audio, would it be possible and work if this went from the wires going to the subs to an aftermarket amp:
Is there an easy splice to the antenna for the REM. My e86 doesn’t have the professional or factory amp in the trunk but does have the subs. I have a mtx amp that ran aftermarket subs I had in another car. I miss the bass that my e85 has when in the e86, I don’t want to rattle my license plate off, but having been a bass player do want to hear some bass lines that are getting lost so I have other subs to run from the mtx amp and still want to keep factory hu.

[OneFastMac]

Originally Posted by Piper1

Not knowing much about wiring in car audio

Honestly, I would recommend learning or having your system installed by a professional. I just bought a Z4 with an aftermarket system installed by someone who “didn’t know much about wiring in car audio” and it caused me a massive great headache. And it’s not over! I’m just making the best of a bad situation until I can swing the cash to really fix their mistakes properly.

Is there an easy splice to the antenna for the REM. My e86 doesn’t have the professional or factory amp in the trunk but does have the subs. I have a mtx amp that ran aftermarket subs I had in another car. I miss the bass that my e85 has when in the e86, I don’t want to rattle my license plate off, but having been a bass player do want to hear some bass lines that are getting lost so I have other subs to run from the mtx amp and still want to keep factory hu.

If you have the “basic” 6 speaker audio system, there’s probably not an amp remote wire at all. Most sub amps have auto turn-on when they receive signal; It’s not ideal but it’s simple and it works so you might go that route. Otherwise you’ll be splicing into something somewhere in the factory wiring harness to get a switched power signal.
I would also recommend using a quality LOC or channel processor if your plan is to keep the factory head unit.

I wish you well, but this thread isn’t where you’ll find what you’re looking for.

[Piper1]

Originally Posted by OneFastMac

Honestly, I would recommend learning or having your system installed by a professional. I just bought a Z4 with an aftermarket system installed by someone who “didn’t know much about wiring in car audio” and it caused me a massive great headache. And it’s not over! I’m just making the best of a bad situation until I can swing the cash to really fix their mistakes properly.



If you have the “basic” 6 speaker audio system, there’s probably not an amp remote wire at all. Most sub amps have auto turn-on when they receive signal; It’s not ideal but it’s simple and it works so you might go that route. Otherwise you’ll be splicing into something somewhere in the factory wiring harness to get a switched power signal.
I would also recommend using a quality LOC or channel processor if your plan is to keep the factory head unit.

I wish you well, but this thread isn’t where you’ll find what you’re looking for.

Thanks through researching some videos got my question answered.

[lyonmt]

Originally Posted by OneFastMac

I recently had an adventure with my Z4's aftermarket audio and I learned that my car was originally equipped with the Carver DSP "Top HiFi" Premium Audio system....

Firstly, thank you for this write-up. I spent an entire day researching this and got a lot of conflicting information. This seems to be the most conclusive thing I found. I appreciate it.

However, I have a few questions on the Z4 radio setup that I was hoping you could answer?

1. The 4 speaker wires at the head unit. Do they go into the Amp's RCA connections? I have wire to RCA adapters.
2. The amp has two left and two right inputs, does this mean that I only use one pair (not all four jacks)? Because If I have a L+, L- creating one RCA and a R+, R- creating a second RCA, I will only have two RCA's.
3. If the answer to #2 is yes, can't I just go from the Head units RCA's to the amp's RCA's? Seems more straight forward to me.
4. What is "Radio remote power"? Most radios have constant and ign/accy. Is Radio remote power the same as ign/accy?
5. I just want to verify that the white Antenna wire is being used for Amp Remote Power?
6. Can I pull the power and ground for the amp from the harness? Seems obvious the answer is yes, but figured I would verify.

[AZZ4]

I recently purchased a 2003 Z4 3.0 with the Carver DSP and without even realizing the car had an amp I replaced the stereo. Of course I wired everything up and had no sound.

I would like to replace the amp with an aftermarket amp but need some guidance as far as what size I need. I will not run the Carver subs since they are 8 ohm. I gather the rest of the speakers are 4 ohm so I need a 4 ohm compatible amplifier. But what size in terms of watts do I need?

How do I match the 16 wires for the remaining 8 speakers to the 4 outputs on a 4 channel amp? Which speakers go to which channel?

Sorry for the elementary questions, but I'd really like to get this stereo working and it wouldn't be worth the cost to take to a professional. Plus, most "pros" in my areas are hacks anyways. I can at least make secure/safe solder connections. I just know squat about car audio terms like bridging, crossover, etc.

[AZZ4]

For the benefit of any others as clueless as me, here's what I did -
I followed OneFastMac's guide for wiring at the dash, only I ran RCA cables from the head unit to the battery box. I connected the 4 RCA cables to the 4 channel inputs on my amp.

The amp I went with was Boss Audio's R1004 400 watt amp.
For now I have just four speakers hooked up, one per channel. I'll rewire the rest once I educate myself better on parallel vs series speaker connection and all that jazz. For now the amp should be pushing 55 watts to each speaker. It sounds decent (tons better than with the factory head unit + dead Carver amp).

[Aloyouis2]

My 2008 e85 came with the Carver/top hifi package. The sound was far less than optimal.

I would describe it as "muddy".

Not wanting to change the appearance of the car and understanding that the sound system was functioning properly I decided to buy a bluetooth adapter. This vastly improved the sound. The stock system has awful converters (D/A).

I then went a step further and installed a bluebus (www.bluebus.dev).

Holy cow!

What a huge improvement! Music from my iPhone is crystal clear and loud. The subwoofers actually thump clearly.

For those of you with the same factory setup as me I highly recommend the bluebus.

[lyonmt]

Originally Posted by Aloyouis2

My 2008 e85 came with the Carver/top hifi package. The sound was far less than optimal.

I would describe it as "muddy".

Not wanting to change the appearance of the car and understanding that the sound system was functioning properly I decided to buy a bluetooth adapter. This vastly improved the sound. The stock system has awful converters (D/A).

I then went a step further and installed a bluebus (www.bluebus.dev).

Holy cow!

What a huge improvement! Music from my iPhone is crystal clear and loud. The subwoofers actually thump clearly.

For those of you with the same factory setup as me I highly recommend the bluebus.

That's really cool.

[OneFastMac]

Originally Posted by AZZ4

For the benefit of any others as clueless as me, here's what I did -
I followed OneFastMac's guide for wiring at the dash, only I ran RCA cables from the head unit to the battery box. I connected the 4 RCA cables to the 4 channel inputs on my amp.

The amp I went with was Boss Audio's R1004 400 watt amp.
For now I have just four speakers hooked up, one per channel. I'll rewire the rest once I educate myself better on parallel vs series speaker connection and all that jazz. For now the amp should be pushing 55 watts to each speaker. It sounds decent (tons better than with the factory head unit + dead Carver amp).

Yes! This is a great solution as well if you want to use low-level speaker output which is sometimes preferred or required by certain amps.
I have since changed my setup around a bit and will update this thread as soon as I can get all of the data together. I went with an 8ch DSP amp and a single-din CarPlay system and have been loving it.

[Veeksi]

Does anyone happen to have any idea what's wrong with my Carver DSP set. It only works properly for one start after I've disconnected car battery and connected it back on. Difference in sound quality is day or night. It's like having only headunit amp vs real amplifier. So to enjoy my audio, I need to disconnect the battery every single time I turn off my engine. Has anyone had this problem, and if has what was the solution (is it DIY fixable or do I need to replace amp or other parts)?

I found this problem accidentaly when I needed to disconnect the battery.