Chorus to Concert upgrade

[joeobrien22]

So in searching for upgrading my basic chorus head unit (8T2 035 152) I've found so much info on upgrading to 3g systems, but I just want to upgrade one step to the concert.
I understand I will need to recode.
My current unit did not throw any codes when two of my speakers were not working so i'm not sure if the concert will act the same.
I don't need the navi, just aux input capability (I know I will need to buy that part)
I also want subwoofer capability (will run the wires) Don't need amplifier as i'm using aftermarket with hi gain input.

Do I need to add speakers ( I don't want any more than my current L/R setup anyway. I have two in dash, two in doors (aftermarket with tweeters) and two channels for the rear doors currently.

Do I need the amplifier?

Do I need to change screen or CAN unit?

[Smac770]

There's two aspects at play here. First, there's the infotainment bus and front end unit. CAN bus with Chorus/Concert/Symphony front end or the MOST bus with MMI front end. There's a variety of MMI versions, 2 vs 3 vs 3+ as well as low vs high, and that's not accounting for the navigation aspects. Second, there's the sound system, which is the amplification and speaker arrangement.

So you have Chorus (and therefore CAN bus), but what speaker system do you have currently? There's the:

Basic - mid/high speaker in the corners of the front dash, and low speaker in the bottom of the front doors, run by a 2-ch amp built into the radio unit.
Basic Plus - similar, but also two speakers in each of the rear doors, treble speaker high in the rear doors and mid-bass speaker low in the rear doors; 4-ch amp in the radio unit.
Standard - adds center channel speaker in the dash and subwoofer in the rear, and a 6-channel external amp in the left rear

It sounds like you have the Basic Plus sound system, and all the CAN bus front end units can run that without additional equipment.

Do you have any idea your PR codes for the 8xx and 9xx range? There's some infotainment system codes in that range. These can be helpful when trying to evaluate parts relevance. It appears 8UL is chorus, 8UD is concert, and 8UM is symphony (ECE).

I believe you are right hand drive there? If we look at the radio/FID (FID = front information display = the screen in the dash) parts catalog:
https://audi.7zap.com/en/rdw/audi+a4...6/0/057-57011/

part 4, the FID unit, there does appear to be different units for Chorus vs Concert/Symphony. Yeah, looking at pages 58-59 of SSP 392, it's clear the display for Concert/Symphony is much nicer than the unit for Chorus. It appears the E rev rolled to the F rev and is currently on the G rev. So any of the three should work for your purpose.

https://audi.7zap.com/en/rdw/audi+a4.../9/971-971090/
This is the dash harness, notice part 24 vs part 31. They are both connecting part - display unit, but one is for 8UD/8UM and the other for 8UL (your chorus). So it looks like you'll need a different plug on the harness also to plug into the different display unit.


Adding a sub, yeah, I'd just add an amp and sub and tap the speaker output wires as a signal source (there won't be any line level signals to tap since the amp is in the head unit).

If you get on erwin for those docs, the wiring diagram and the "repair manual - communications" will be your big two for modifying your car on this topic. My US spec versions don't even discuss Chorus as US spec B8 only use Concert (if not navigation equipped) or MMI High (if navigation equipped).


There's also Kufatec, the normal go to for electronic retrofits. They have the cable as well as a complete kit with Concert unit, screen, cabling, etc.
https://www.kufatec.com/en/audi/a4/a...symphony-39322
https://www.kufatec.com/en/audi/a4/a...di-a4-8k-37596

[joeobrien22]

Hello again
From that description I have the basic plus setup

The only code semi related to the infotainment system on my sticker seems to be PRCode: 9Q2 = Multi-function display/on-board computerwith check control

I definitely have the chorus 3 though.

So if I:
1. double check that the pins are the same in the main harness to radio
2. Get the proper display
3. Get proper display connector
4. add pins into harness for the aux input
5. Recode in VCDS

That should do it without adding the amp and other speakers?

I was going to go for the Alpine upgrade, but they were in between the x702 and x703 models at the time, now with work restrictions i'm not going to spend the 1500 euro on that yet, so i'm going to look for parts on ebay and parts resellers I think.

[Smac770]

Pretty much is what I see. Hard to say since I don't have a wiring diagram that includes the Chorus, so no way for me to verify how the connector pinouts are vary, but it seems a straight-forward task.

[joeobrien22]

If I want to have the seperate subwoofer volume control, looks like I'll have to install the stock amp... Unfortunate, but I suppose I could add a non factory control from my amp to the center console or something.

[Smac770]

I don't think you get a separate sub output level control; I don't have one on my MMI 2G High + B&O sound system. I think they added a midrange "slider" to the tone controls later (MMI 3G or at the refresh, not sure), but still no "subwoofer level" that I remember. Have you seen a Concert head unit in a B8 A4 with a subwoofer output level control? Did it have the 6-ch standard or 10-ch B&O sound system?

An aftermarket amp might work better in that regard anyway. My uncle picked up a a sub amp for his car to replace a failed unit, https://rockfordfosgate.com/products/details/r2-500x1/. It included a long cable with a knob on it for subwoofer amp level control that he mounted in the console, which was good for him. Sometimes he likes to boom, sometimes he doesn't. And turning the knob is a lot easier than digging through a menu system.

[joeobrien22]

Actually it was the A3 I had that I'm thinking of. I am just adding the sub for low frequency makeup from 20 to 60 hz or so. unfortunately that frequency range is dramatically rolled off. I have an aftermarket solution in the JL Audio Cleansweep. https://www.crutchfield.com/S-0hQnBM...leanSweep.html, but still having trouble locating mini molex power connector for it. In the mean time I am tapped into the full range outputs to the speakers. The frequency gain is all over the place. I suppose the only true solution to someone as picky as I would be to go with the alpine eventually.

[joeobrien22]

Just curious about component protection. I've seen a few posts about the EEPROM on 3g units, it seems to be universally the same in all units.
Will eeprom chip from chorus work with concert? I do circuit board repair anyway, would be a breeze, just not sure if coding on the chips contain different options for chorus v concert
I can only find the radio's on EBAY and I doubt they have the VIN of the car it came from if AUDI asks, though they should have a database I would assume.

[Smac770]

I don't mess with the eeproms; if I bought a new setup to put in the car, I'd just go to the dealership and let them code out the CP for the one hour rate.

If it were the same unit, such as a repair operation, maybe. But differing units, unlikely to be that simple. More likely, assuming Vag Com Pro can read/write the eeprom on the CAN head units, you'd do it like you would for MMI, read the old CP blocks and write it to the new eeprom. But no idea if anyone has tried to use VCP to reset the CP on a Concert head unit.

Or you could just find a shop around that has ODIS; they should be able to do the CP clear same as a dealership.