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F80/F82/F83 M3 and M4 (2015 - Current)
F80 BMW M3 sedan, F82 BMW M4 coupe and F83 M4 convertible forum. This 5th generation M3 and all new M4 features a 3.0 liter twin turbo engine (engine code S55) 425hp and 406lbs of torque! Heavy use of light weight materials makes this generation lighter and faster then the outgoing E9x M3.

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Old 02-05-2017, 07:13 AM
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Technic Technic is offline
OEM Audio PnP Integration
Location: Florida
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Posts: 7,682
Mein Auto: 2017 M3
Notes on a 2017 M3 with HK system and replacement of MOST OEM amp

For those that find the audio quality of the highest audio option in BMWs lacking or just having a damaged/non-functional OEM amp, replacing the OEM amp with higher quality aftermarket amps and DSP has been very difficult or just costly.

The OEM amp in the majority of Top HiFi systems (Logic7, Harman Kardon, Individual Audio, Bang & Olufsen) since MY2002 has been difficult to replace for the simple reason that its inputs are MOST (Media Oriented Systems Transport) digital proprietary. No plain harness, no standard digital to analog converter can decode this proprietary digital signal. So no analog or digital (Toslink optical cable inputs) aftermarket amp/DSP can interface with this MOST protocol.

The "old school" way of integrating an aftermarket amp to the analog/high level outputs of the MOST OEM amp can be performed but the audio quality results of such integration will be less than optimal:

- The OEM amp is designed to change its equalization and bass levels with speed so any tuning made while stationary will be useless -the OEM amp will change its tune at different speeds
- The OEM amp outputs are high level up to 35V peaks in some versions. Very few aftermarket devices can support 35V inputs long term. Some will just burn its input stage in a few weeks.
- In my own particular case, I found the audio in all OEM amps muffled, not crisp like aftermarket, regardless if the OEM amp is HiFi (analog) or MOST. Like the sound pass thru a sock regardless of treble adjustment. Changing the speakers can clear that dullness a bit but to me is never enough. Changing the OEM amp always remove that muffled sound completely. Even with OEM speakers.

So what to do with a MOST OEM amp?

There are two ways of fully integrating an aftermarket amp/DSP by replacing the MOST OEM amp:

Option 1: replace the OEM amp with a MOST converter (analog or Toslink outputs)
Option 2: code the iDrive/OEM HU to output analog (either low- or high level) instead of MOST

Either of these two options will keep all the OEM audio features already present in your BMW (radio, Bluetooth, Assist, USB, AUX, Apple CarPlay, gongs) with very particular exceptions (note below), while greatly improving the audio quality of all sources even with OEM speakers.

This is the second MOST OEM amp replacement that I have done (2008 M3 with Individual Audio was first) but the first applying both methods of integration.

My 2017 M3 is equipped with the HK system and ASD module as standard, and the Apple CarPlay option. HK system is comprised of 16 speakers (7 mids, 7 tweeters, 2 woofers) and a 9ch OEM amp of a total of 600W peak output. Aftermarket equipment to be installed:

- Audison DMI MOST-Toslink Converter
- Alpine PXA-H800 DSP with Toslink inputs
- Arc Audio XDi V2 1100.5 5ch amp
- Arc Audio XDi V2 600.4 4ch amp
- JL Audio 10w6v3 10" sub with a MusicarNW F30/80 custom sub enclosure

All speakers kept OEM.

Install of aftermarket amplifiers:

- Removal of OEM amp

- Unplug three connections from OEM amp: 20-pin female, 12V/ground, MOST fiber optics connectors:

- ASD module 42-pin connector to be unplugged:

- Top HiFi OEM amp replacement hardware kit (20-pin male speaker output harness + OEM MOST termination socket) for MOST converter applications:

- Arc Audio "Power Pack" custom rack pre-wired with Top HiFi OEM amp replacement kit, speaker inputs (RCA cables), and power/ground (Anderson SB120 connector kits)

- Replaced incomplete OEM battery distribution block with a new and complete version (no need to disconnect battery, just distribution block):

Top: distribution block installed at factory.
Bottom: same P/N distribution block ordered at local dealer

Power cables ready to be plugged into OEM distribution block:

- Replaced standard left trunk trim with OEM DVD Changer trunk trim (P/N 51487246299) to clear Arc Audio amps and mounted JL Audio sub:

- Custom PXA-H800 module install:

- PXA-H800 controller custom faceplate mount:

- Tune PXA-H800 to interior of car via included microphone:

MOST converter interface:

Option 1: Audison DMI Toslink into PXA-H800

- This MOST socket P/N 61136917978 is required to properly terminate the MOST terminal (included with the Top HiFi OEM amp replacement hardware kit for MOST converter applications) :

MOST connector (socket + terminal) complete:

- Insert MOST connector into MOST extension cable and connect to DMI

- DMI connects to PXA-H800 using a generic Toslink cable (not shown)

Right off the bat: sound is fantastic. Sound is crystal clear even with OEM speakers. Bass is solid everywhere, highs can be bright or soft depending of adjustments. PXA-H800 has Dolby Pro Logic II and its own Euphony 5.1 decoders with a vast number of adjustments in the digital domain so anything can be adjusted -bass, midbass, highs, voices, surround, time alignment, soundstages (driver, passengers, all) anything. If surround sound is not desired then there is a Stereo setting. But what got me from the get go is how clear the sound was, especially the absence of the "hiss" commonly found in analog sources and the complete elimination of the muffled sound in all sources.

The only problem with the DMI integration and this particular install is that the DMI firmware is not updated for the MY2017 iDrive 5 (NBT Evo II). Most of the audio was properly decoded except Bluetooth phone and Nav Guidance audio. Callers can hear me but I cannot hear them. Nav Guidance audio was heard only in its last words. This may or may not apply to MY2016 and before. Check your own implementation.

After testing I found out that if I turn up and down the volume during a call or during Nav guidance then audio will be heard. Unfortunately the audio muting returned each and every time in the next call or Nav guidance audio, so this "volume up and down" has to be done each and every time. I contacted mObridge, the manufacturer of this MOST converter (the Audison DMI is a repackaged mObridge DA1), and after providing them with MOST traffic data they concluded that their latest firmware was not able to decode this MY2017 iDrive 5 audio and that they will take some time to develop a solution.

I did not want to wait for a solution that could take months so the DMI was out -that is the reason that there are no installed photos of it.

BMW OEM Audio PnP integration

Last edited by Technic; 05-11-2017 at 01:01 PM.
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Old 02-05-2017, 07:13 AM
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Technic Technic is offline
OEM Audio PnP Integration
Location: Florida
Join Date: Jun 2002
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Mein Auto: 2017 M3
Option 2: code the iDrive/OEM HU to output analog

Option 2: code the iDrive/OEM HU to output analog (either low- or high level) instead of MOST

There are two analog output options that may be coded:

- Stereo
  • OEM HU/iDrive unit directly powering front, rear and underseat woofers
  • 4 channel output split into 6 speakers: front speakers connected in parallel with underseat woofers
  • front outputs are full range, rear outputs are high passed
  • (4) 4" mids and (2) 6.5" woofers. No tweeters
  • 15W x 4 (Professional Radio)/25W x 4 (iDrive) max power high level outputs

- HiFi
  • OEM HU/iDrive unit connected to a trunk mounted 6ch or 7ch OEM amp powering up to 12 speakers
  • OEM HU/iDrive unit outputs are analog, low level*, balanced, flat signals.
  • OEM amp outputs are high level, slightly tuned signals for front/rear/center (if available)/woofers)
* depending of who you ask, these balanced output signals can also be categorized as high level but with very low power not significant enough to drive a speaker directly with authority

All iDrive and OEM HU units since the MY2002 7-Series (first introduction of the MOST OEM amp) have at least one analog output coding option that is effective for aftermarket integration. For example, E6x chassis cars (5-, 6- and 7-Series) will have only the Stereo coding option that is usable for aftermarket amps/DSP. Their HiFi option mixes high level signals (iDrive unit outputs directly powering front and rear speakers with built in high pass filters) with low level signals (OEM amp low passed inputs to power the underseat woofers). It is more effective to code these units to Stereo as there will be no high + low level mixing. Note for Stereo coding: a DSP with correcting (flat) OEM signals feature is required.

For all BMW after MY2002 with the availability of HiFi (676) with a 6ch or 7ch OEM amp with 42-pin connector available as a factory option, the preferred coding from Top HiFi is to HiFi. Coding to HiFi requires balanced inputs amp or DSP. The PXA-H800 DSP accepts balanced inputs in this install example.

MY2017 M3 coding HK to HiFi:

RCA cable extensions must be performed before coding, as there are no wires from the OEM HU/iDrive unit to the trunk, only fiber optics.

- Remove OEM iDrive unit

- Unplug Quadralock connector from iDrive unit

- Notice the two columns of 8 empty sockets to the right of the Quadralock. These are the audio signal outputs of the iDrive unit:

- Depending of the type of Quadralock in your unit (Type 1 up to ~MY2010, Type 2 is the current version) you will need to remove a blue pin retainer from the main connector before inserting the new wires:

- Use the Top HiFi OEM amp replacement hardware kit for analog-coding applications (20-pin male pigtail + MOST socket + MOST Termination ring + 17' flat 4ch RCA cables + Quadralock RCA adapters):

- Insert 4 pairs (front and rear signals) of female RCA cables terminated with OEM female pins:

- Use a wire fisher to run male RCA extension cables (I use 17' long cables) from the back of the iDrive unit to the side of the console and then to the trunk:

- You can tap pin 13 at the Quadralock connector as your OEM remote signal (turns on by opening a door/trunk, and turns off 2-8 minutes after shutting engine off and closing all doors/trunk) and run a wire at the same time that you are running the RCA cables to the trunk. But be advised that some BMW models do not have enough current or voltage in that pin 13 to turn on your device. I would suggest using any other 12V switched signal in your car as your remote, like any of the 12V accessory sockets. I used the trunk 12V accessory socket as my remote.

- Once RCA cables are in the trunk then terminate the MOST terminal with a MOST termination ring:

MOST termination ring is comprised of two parts: the MOST socket (61136917978) and the MOST ring (61136917541):

Plug RCA cables to the amp or DSP. In this particular install, the RCA cables were plugged into the PXA-H800 RCA inputs.

Hardware part is completed.


There are two ways of coding HiFi: VO code or Direct unit code. See coding forum for details

- VO (Vehicle Order) code will remove the HK 688 option from vehicle order and replace it with HiFi 676. Then code HU_NBT_EVO ECU.
- Direct unit coding will code the NBT Evo from its inside FDL, by looking at where 688 is and changing it to 676. Then code FDL.

I selected VO code for this output change as it is the correct and complete way of setting the HU_NBT_EVO to fully output analog from all its sources. Direct unit code in the HU_NBT_Evo disables audio from the CD, USB stick and Music Collection if changes are only done at the AUDIO_SYSTEM and AMPLIFIER_VARIANT.

- Perform a VO change from 688 to 676 (refer to for VO change basic instructions)

- Code only HU_NBT_EVO

Coding completed

Sound is less clear than digital but still superior to the OEM amp in all areas, especially the muffled sound is completely gone. Extra tuning is required to eliminate analog hiss but once this is done sound quality still is superior to the OEM amp even with OEM speakers. Bass sounds deeper than optical but that is more a function of what the PXA-H800 does with analog inputs than what it does with digital inputs. OEM speakers handle the extra power of the Arc Audio amps without any problems. OEM woofers can be tuned to remove most of the flabbiness that can be heard with the OEM amp when trying to be sub and woofers at the same time.

No issues at all with the iDrive audio -all sources work OEM. Even Sirius sounds much better than OEM. And for those looking for a low cost replacement of the MOST OEM amp, coding is much cheaper than using a MOST decoder by at least $600.

Best sound = digital
Best sound at the lowest price = coding

BMW OEM Audio PnP integration

Last edited by Technic; 05-11-2017 at 01:09 PM.
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Old 03-05-2017, 10:15 AM
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Technic Technic is offline
OEM Audio PnP Integration
Location: Florida
Join Date: Jun 2002
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Mein Auto: 2017 M3
Upgrades: Helix DSP.2, JL Audio C3 Tweeters, Morel Integra 424 Hybrid, Eton B 150 USB BMW woofers

A Helix DSP.2 replaced the PXA-H800 after 6 years of service in three installs once started malfunctioning right after this install:

JL Audio C3 tweeters replaced the front OEM HK tweeters:

Morel Integra 424 Hybrid replaced the OEM HK center component (mid + tweeter):

Eton B 150 USB BMW woofers replaced the OEM HK woofers:


The Helix DSP.2 was chosen as the replacement of the H800 for its simplicity of installation and more modern DSP architecture. Considering that the H800 required all its tricks (ImprintEQ, Euphony, Dolby Pro Logic II, MX) to sound fantastic, the Helix DSP.2 only requires its more up-to-date 64-bit fixed point (vs two 32-bit floating point DSP in the H800) to sound equally fantastic. There is a dynamism in the music now that was quite difficult to achieve in the H800 and its myriad of adjustments. The major improvement of the DSP.2 over the H800 is the capability of the DSP.2 to adjust the input (level and EQ) so hiss can be more effectively eliminated than before without affecting the output tune.

Once the DSP.2 was installed and tuned then I started noticing certain sound quality issues with this install that were masked by the H800 but now they became relevant. Midbass coming from the OEM woofers required as much tuning as before to remove its "boominess". Front OEM tweeters were tiring after long drives. I noticed that front stage voices in certain known songs were not as clear as I remember them. Tried more tuning for hours to no avail.

So I decided to replace the OEM front tweeters, center speaker and woofers with aftermarket, a method that I have used in HiFi systems for years as those are the OEM speakers that suck the most. I was expecting that the HK OEM speakers were really enough of an improvement over the HiFi and specially with aftermarket DSP and amps, and they are up to an extent. However they still are not as clear and precise as to achieve a truly satisfying sound quality improvement with aftermarket.

JL Audio C3 tweeters were chosen as they are silk (compared with what it seems like aluminum OEM tweeters) very precise, soft, low cost, and they kind of snaps into the OEM tweeter mounts with little work. The Morel Integra 424 Hybrid" coaxial was selected as I always consider the 4" mids from Morel as the best 4" drivers out there regardless of price. MusicarNW provided a single 424 and I could not say no. Then the OEM woofers were replaced by a pair of Eton B 150 USB BMW woofers from my last install. These are solid midbass woofers without any boominess. These 4ohm woofers are slightly louder than the 7ohms OEM woofers as well.


Improved clarity and midbass where it can be heard and appreciated, at the front stage. That little clarity in the voices that was missing to me is no more. Most probably this improvement was the difference between silk and aluminum and the way that my hearing reacts to it, but I don't feel tired of hearing any more with this swap. The Eton woofers match the sub much better than the OEM woofers. Which does not surprise me as I have noticed in previous HK installs that the OEM woofers amplified by aftermarket amp are much better sounding without a trunk sub.


Replacing the HK OEM amp, front tweeters and OEM woofers with aftermarket fixes all the OEM audio quality problems at once for the most effective upgrade for the money.

BMW OEM Audio PnP integration
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Old 05-11-2017, 01:08 PM
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Technic Technic is offline
OEM Audio PnP Integration
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Mein Auto: 2017 M3
Top HiFi OEM amp replacement hardware kits are available.

BMW OEM Audio PnP integration
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