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PR-9VD 9.1 sound system retrofit

:::warning This is experimental. 9VD retrofits had been done before, but not exactly like this one.

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Intro

Some vehicles like Audi A3 (8V) and Seat Leon MK3 (5F) had option of PR-9VD sound system (Audi Sound System, Seat Sound System). It's 9.1 configuration with 10 speakers connected to MIB main unit internal 6-channel amplifier, without MOST and external amplifier (like Bose, B&O, Dynaudio, Fender…).

One of the most popular audio configs is PR-8RM, 8 speakers connected to 4 audio channels of the MIB internal amplifier. Since some MIBs internal amp has 6 channels, this leaves 2 channels unused. 5th for subwoofer under the trunk floor, 6th for front center under the dashboard.

In addition there should be a more precise equalizer available (5 slider instead of 3) + separate subwoofer control adjustment.

Requirements

  1. MIB main unit with 6-channel internal amplifier,
  2. Diagnostic interface to change coding (VCDS, OBDeleven…),
  3. Diagnostic interfaca to upload parametrization (VCP, CarScanner…),
  4. Additional speakers (front center + subwoofer), cables, terminals, connectors.

:::info Some door speakers are different for 8.0 setup and 9.1 setup (4Ω 20W vs 2Ω 40W).

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Connection diagram

:::info Pending

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Wiring

  1. Quadlock, pin 9 (positive) and pin 13 (negative) for subwoofer R211.
  2. Quadlock, pin 10 (positive) and pin 14 (negative) for front center R208.

Parametrization

  1. Module 0x5F, Parametrization, address 0x000200 - this adjusts the unit identifier string.
  2. Module 0x5F, Parametrization, address 0x003B00 - this controls GUI (equalizer + subwoofer sliders).
  3. Module 0x5F, Parametrization, address 0x003000 - this controls sound curves for all audio channels.

:::info This file should be picked according to your car options (model, body style, steering wheel side).

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Coding

  1. Module 0x5F, Long Coding, bytes 4-7, new value FF 0A 00 00 - this sets speakers configuration.
  2. Module 0x5F, Long Coding, byte 11, new value 01 - this makes sure that the unit is set to internal amplifier.

VW with 9VD?

:::info What I'm trying to accomplish is to enable 9.1 config in VW Golf MK7, which never had the PR-9VD option available from the factory. This can be done in MHI2 units, but not MST2 units.

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Connected speakers to quadlock, send dataset from Seat Leon Kombi Left-Hand-Drive with 9VD to 0x003000, coded 0x5F bytes 4-7 with FF0A0000.

Effect? No sound from additional speakers, no new equalizer controls, 0x5F fault code about incorrectly coded module. It looks like VW audio processing not the same as in Seat and Skoda. VW app controls 4 channels, Seat can control 6 channels, Skoda has an individual option with virtual subwoofer.

Later on I opened my main unit only to find out that it's missing some hardware. Looks like VW version of MST2 main unit not equipped with required hardware for additional audio channels. Below you will find picture of Seat MST2 unit with 6-channel internal amp, and VW MST2 units with 4-channel internal amp, to compare the hardware differences.

Seat Leon (5F) main unit with 6-channel internal audio amplifier

VW Golf (5G) main unit with 4-channel internal audio amplifier

Sources and reference