BMW i4 M50 Harman Kardon demobuild with amp upgrade

BMW i4 M50 Harman Kardon demobuild with amp upgrade

This article is about what is possible to do if you want only the best when upgrading BMW i4 Harman Kardon surround sound system.

Focus is not so much how, because most things like replacing speakers are covered in previous blogs:

BMW i4 Harman Kardon Audio Upgrade

BMW i4 Base Audio & HiFi 676 Upgrade

But we will go through how to add DSP amplifier to Harman Kardon and lots of pics from all upgrade phases.

i4 M50 democar audio built specs

Car is fully specced 2023 model and several speaker brands, amps, subs etc. has been tested during time and project is now mostly finished.

List of components:

Front mid/high speakers: Morel IR-BMW42 component speakers

Front door woofers: AI-Sonic Solo 6 with i4 custom MDF adapters

Center speaker: Morel IR-BMW42CTR

Rear door & shelf speakers: Stock HK

Amplifier: Match UP 10 DSP with MEC Analog in module and modified PP-BMW 1.9RAM-HK harness with 3ch Booster Y-harness (coming soon)

Amp controller: Match / Helix Conductor

Sub amplifier: Match UP 1FX

Subwoofer(s): Currently testing Phoenix Gold ZX210PBS and Hertz MPBX 300 S2 12". Later going to build fiberglass enclosure for AI-Sonic Solo 10.

Front stage speakers

To this date we have tested several mid/high component speakers like Musway CSB4.2C, Rainbow IL-C4.2C (discontinued) and DLS CRPP-BMW1.4 but only with stock amp. But if you are looking for the best then hand made Morel IR-BMW42 reference series it is.

For woofers there has been GAS 8ohm SPL speakers briefly installed, but later swapped to 4ohm AI-Sonic Solo 6 that surprisingly worked ok with stock amp when other 4ohms ones didn't. Musway MG6.2W woofers were also in place for a while with Audison M12.14 amp and were almost as good as Solo 6 just half the price. But to choose the best Solo 6 it is.

Front mid/high component speakers and door woofers.

Door speakers installed.

Amplifier upgrade

Upgrading the amp is usually the best way to make audio system better and with DSP you get free adjustability on top of more power and better dynamics. But replacing the amp or amps is not so simple in BMW's that have iDrive 7 or newer as audio signal from MGU (Multimedia Graphics Unit) head unit comes via Ethernet BUS and RAM (Receiver Audio Module) amplifier is responsible for making all audio sounds like blinkers and also includes hardware to the radio. So basically it can't be removed, but it's possible to get pure audio signal for external amp with BMW Ethernet decoder. We have tested and installed few, but it is not recommended for Harman Kardon as HK has second Booster amp for bass and decoder doesn't communicate with booster so there is no bass from sounds that RAM sends to booster like radio (Spotify / BT works). Decoder works well with base audio or HiFi 676 that doesn't have RAM, but there are some EV specific sounds like Iconic sounds or start up sound that decoder doesn't support so not recommended for i4. But for ICE cars very good option to get pure unfiltered audio signal.

Video of testing this module in i4 can be found -> HERE

So if you wanna keep all cars sounds as stock then only option is route speaker level signals through DSP-amplifier. Audiotec-Fischer has made plug&play solutions to almost all iDrive 7-> cars including harnesses and sound setups using either Match UP 8DSP or 10DSP amp depending cars audio option. Base Audio and HiFi 676 are basically the same when it comes to amplifier and that is the case also with i4. But i4's Harman Kardon differs from ICE cars as it has 3 woofers (doors+trunk) instead of two underseat woofers. There isn't plug&play solution at least for now from any car audio manufacturer, but with harness modification Match UP 10DSP can be installed to i4 Harman Kardon.

NOTICE! Match UP 10DSP doesn't have enough power/channels to drive trunk subwoofer so mono amp or active sub is also required.

Modifying the harness and installing the amp

Needed parts:

  • Match UP 10DSP amplifier
  • Match / Helix Conductor controller or URC.3
  • Match MEC ANALOG IN module - UP 10DSP
  • Match PP-BMW 1.9RAM-HK harness
  • 3ch Booster Y-harness (made by Technic PnP)
  • Fuse holder for example mini ANL with 60A fuse (or bigger if active sub / mono amp is also behind same fuse)
  • 6mm2 / 10 AWG power cable about 3m from cars fuse box to amp and 0,3m from amp to grounding point
  • Speaker wire and connectors

Modifying the harness is quite simple. Just cut out Booster connector part from Match harness like in the picture. White and white/black are then connected to 3ch booster harnesses left door woofer cables the same way and grey ones are right door woofer. Note that input/output goes just like in Match harness. All wires are clearly marked in 3ch Booster harness.

Then there is trunk woofers in/out wires left and actually only wires coming from Booster male connector are needed and those need to be extended to reach amplifiers analog in card. So UP10 powers door woofers just like it would power underseat subs. And trunk woofers signal goes to analog in card and that is routed in amps software to RCA sub out. That way you can control both door woofers and subwoofer levels separately with Conductor or URC.3 remote. Also amps woofer inputs and analog in cards input can and need be set to handle max 32V signal levels that is required (setting to 16V from software is good).

Amp needs to be opened and set input G+H jumper to 32V position. Same for Analog In module and just push into its place on circuit board. There are clear instructions in amps and modules manual.

Next step is to route power cable behind right side fuse box to left side and that is explained in previous blogs. Then just plug in all connectors and tie cables neatly. Amp fits nicely in the wheel arch but is a tight fit when putting left side panel back. Before that it is good to connect and route RCA and remote cables to right side, controller cable to front and USB cable in place.

NOTE! Center channels input wire is not used in Match harness so it can stay tied up somewhere. There are not enough inputs in amp so it will be made from FL+FR using amps "Real Center" algorithm. In other BMW's Analog In module is used for that, but in i4 case we use it for trunk sub.

Match / Helix Conductor installed. It can be programmed from PC-Tool tuning software to control almost everything including switching sound setup. Color options are almost infinite and in this case blue is always on for adjusting sub output level (Analog In module) and pressing once knob turns to purple to adjust door woofers level.

TIP: Third press can be used for MASTER VOLUME and if you boost main dB level from software you can hear Iconic sounds much louder. That also affects other sounds like turn signals and gong, but for daily driving just put master volume few dB quieter. Still nice feature to get full control of cars sounds and maybe scare friends in sport boost and loud iconic sounds coming from powerful sound system.

Conductor installed drilling a hole to stock plastic piece and cable routed underneath.

Subwoofer and amp

Let's start with the amp. First one was Musway ONE600, but after Audiotec-Fischer released its first mono amp in Match lineup and main amp is also Match, decision to replace was easy. Model is 1FX and it gives around 1000Wrms in a small package. Other good properties for i4 Harman Kardon is that it can also take speaker level signal from stock Booster amp (up to 32V). And when using Match DSP there is switch to turn off amps internal crossover (DirectDSP) so all adjustment can be made from UP 10DSP. In this install we used line level RCA from UP10 and input is also a single RCA connector like in UP10's output. Voltage level is perfectly matched with UP10 meaning you can set gain to max that is 3V what UP gives.

For different applications there is jumper inside the amp also for 1-6V range and if amp's speaker signal is used then same jumper means 6-32V range. So that need to be moved if signal is taken directly from Booster amps speaker output but in this case we use UP10's line level signal so lower value position is correct.

Also Helix SRC remote can be added for adjusting sub level but in this case Conductor takes care of that.

Amp installed to right side "pocket" near the fuse box so 10mm2 / 8 AWG cable is sufficient.

And final piece of the puzzle - subwoofer. Actually this is still ongoing process and currently testing Phoenix Gold ZX210PBS that has 10" woofer and another 10" is passive without motor. When using passive radiator enclosure acts like ported but can be made much smaller in volume than ported. PG sub has really sharp and intense kick and goes low with enough SPL, but when playing really high volumes it loses control maybe because of passive radiator. Or maybe needs some more break in. But for everyday listening gives more than enough and best feature is that it fits under trunks cover and some other stuff like tyre repair kit with jack, compressor etc. fits also under the sub.

Some modification was needed to fit the sub.

Another sub that sometimes goes into trunk is Hertz MPBX300 S2. This is 12" woofer in sealed enclosure and goes really low with lot's of SPL. Negative thing is that it's not hidden, but swapping between PG takes few minutes.

Future plan is to make fiberglass enclosure to trunks storage compartment and use AI-Sonic Solo 10. Pics and comments added when it's finished....


And lastly the most important DSP tuning.

The sound?

Well you can imagine. Plays smoothly and clearly, stereo image perfectly centered, lots dynamics and SPL if needed. With Solo 6 door woofers sub is almost not needed and can be taken out time to time if all cargo space is needed, but with Phoenix Gold sub that is not an issue. With full control of master volume you can really make Iconic sounds rumble from speakers when pushing the pedal in sport boost.

Match UP 10DSP amp set for i4 in webshop ->

Sound setup included.

International customers please contact -> to get quote for the set incl. shipping

- Kimmo / Audiokit


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