# BMW Audio Coding (non-most)



## MM22000 (May 21, 2021)

Seeking for a linear, non-equalised analogue output, I encountered several settings in the Headunit of my F10 (2014).

My findings regarding the variant so far:


Switching from Stereo to Hifi does not provide a low level output instead of high-level. It does reduce the level of upper frequency range compared to Stereo
Variants 3 and 4 provide heavy increase in bass level; its sounds "boomy"
Variant 2: noticeable reduction of high frequencies
I don't believe that vari1 is linear, but closed ot linear that the other setting of var

I adopted the frequency crossover for the Focals build in the door panels. The measurements of the door panel show a nice decreasing response. Surprisingly, var1 increases mid to high frequencies.

Moving the amplifier variant from internal to external

definitely reduces the output level of the HU. I have not measured it, but it may provide a voltage in the low-level range
more noticable is the fact that the bass is more linear
Even, when the setting is external, the variant (1-4) settings are effective, but with reduced impact

My interim conclusion is that there are 3 setting equalising the frequency response for (non-most) amplified BMW-Systems:

AUDIO-SYSTEM
AUDIO_SYSTEM_VAR
AMPLIFIER_VARIANT
All three are summed up, which makes it difficult to find a proper setting.

Below other settings are listed which I could not verify.

I would wish to share any experiance regarind those setting. Has anyone measured the frequency response from aux-input to HU-output?

Best wishes
Michael





AUDIO_TUNER_TRAFFICAUDIO_SYSTEMstereo0x00BMWLevel increase in upper frequency rangehifi0x01actual settingAUDIO_TUNER_TRAFFICAUDIO_SYSTEM_VARvariant_10x00Less bass compared to var2variant_20x01Less high frequency compared to var1, var3, var4variant_30x02high bass levelvariant_40x03high bass levelAUDIO_TUNER_TRAFFICAMPLIFIER_VARIANTinternal0x00BMWexternal0x01actual settingSignal seem to be not much lower than "internal"; Sound appears to be much more linear, most recogniseable at low frequencies.AUDIO_TUNER_TRAFFICAUDIO_PROFILEwert_010x00BMWwert_020x01No difference recognisedAUDIO_TUNER_TRAFFICAUDIO_OFFSETnicht_aktiv0x00actual settingNo difference recognisedaktiv0x01BMW


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## GrM (Feb 11, 2021)

Is this meant to be purely informative or is there a question here I’m missing?
I’d assume the frequency response through stock speakers would be flat when the EQ is set to flat and all options are turned off. Except for EQ curves that might be volume dependent. Most manufacturers have their stock HUs tuned so that the frequency response through the stock speakers is flat, which is why adding aftermarket speakers etc. messes everything up, because the stock HUs are tuned to be flat with OEM speakers etc. (and to protect the nickel store speakers they use, that’d be the only reason an OEM setup wouldn’t be tuned flat with a flat EQ setting and all other audio options turned off).

I don’t have experience with BMWs (not anything made this millennium) but, unless I am mistaken (someone please correct me if I am) this is par for the course with every vehicle manufacturer. BMW being a luxury brand would almost certainly bother to have their OEM systems tuned to be flat. The other non eq options are primarily to make them sound as good as possible for as many different people as possible using software rather than hardware.


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## Old'sCool (May 16, 2021)

The easiest solution is to trade that F10 in on an e39, or better, e36 hatch. (If audio is important.)

The DSP system in newer Bimmers has me referring customers elsewhere. I'm not going to spend 8 hours tuning a car to net similar SQ to stock. F(10) that.


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## RedSwede (Aug 11, 2017)

I've tried all variants (or at least I think I went through all combinations) of BMW audio config. The long and the short, none were close enough to neutral to be useful. Some were more EQ'd than others, but ultimately, they are all compromised. I switched to using the Optical in on the Helix, with auto-sense switching for phone/nav/radio. This was night and day difference in all regards. Don't bother with OEM integration for anything other than occasion output like Nav or parking sensors.

(BMW may be a bit awkward here, but I am very impressed at midbass performance from the underseat locations - if you can cross to the doors at an appropriately low frequency, and don't rely on them for sub-bass)


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## MM22000 (May 21, 2021)

So far, I can confirm precisely your experience...
Here an example: Hifi, internal amp, var 4 (db...electrical)








I have not completely given up yet  I can also code "individual" and "internal amplifier", delivering a more linear analogue output. However, it may be better than others but still not sufficiently linear - measurment tomorrow.

Thank you for the info regarding the subs. I have installed 2 Focals as sub, 3 (incl mono-center) Focal ES100K and Rainbow 2-way for the rear.
With the focal impulse amp I can cut the front speakers at 75Hz or run them full. If you do not require very high volumes, full might be also an option. Due to the lack of linear input, I have not measured the speakers response in the car yet. 

Do you have an recommendation for a most to analouge output device?

Best 
Michael


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## MM22000 (May 21, 2021)

There is one setting delivering a useful output:
Coding: Hifi, internal amp, audio offset on, audio var 2, audio profile 1 















All other settings like tophifi, individual, harman kardon, var 4, 3, 1 etc. have weather a too high level around 3-5kHz and/or crazy EQs for the bass.
Also I encoutered that external amplifier setting ist mostly worse than internal amplifier setting.
Interestingly the settings for audio profile do matter tremendously. I measured all of them ....

For the avove measurement it has to be noted:

Focal ES100K crossover has been modified by inserting an l-pad in order to reduce the level of the tweeter by -17dB !! seventeen! (a serial resistance would change the x-over point) Also the tweeter (12dB/12dB) is now connected with reverse phase (not like Focal)
Capacitors have been exchanged for higher quality and the low-filter has been completely removed from the crossover (...a series electrolytic capacitor of 220µF is not a good idea for high quality sound.)
Measurement taken far-field from the seat. Therefore, values below 400Hz can be considered as not valid
Dual gate measurement (20-200ms) , AUX level 20, HU 3/4 volume
Left graph shows closer speakers respone, right the more distant

Just to show examples for other settings:

High_premium









Harmann Kardon









Stereo









Best
M


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## RedSwede (Aug 11, 2017)

Well you've definitely got further than I have. I gave up, and just flattened it as best I could with Helix input EQ. 

But even with a totally flat OP from the HU, I bet it'd still be the best upgrade you could do to have a direct input bypassing the whole thing for everything except system sounds.


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## MM22000 (May 21, 2021)

Yes, the recommendation is definetely a MOST-bus adapter for bypassing  I nearly purchased a Mobridge-Pro.

For the modification of the crossover, some experiance, a lot of time, patience and good measuring equipment is required....


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## JVD240 (Sep 7, 2009)

Why not measure the actual amplifier freq. response? From what I can see these are all acoustic measurements.

What are you trying to accomplish?

A DSP will be able to equalize the factory output assuming it is linear throughout the volume range.


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## MM22000 (May 21, 2021)

Exactly, acoustical measurements.
I do not like the concept of transfering analogue signals to digital and re-transfer them to analogue. You lose quality of the signal, despite an optimised frequency response.
As I bought already 2 amps without most input or dsp, I decided to find the most suitable setting of the BMW (out of approximately 100 options) by measuring the amps electrical response and adopt the x-over.
Modifying the crossover is a bit iterative. You can compensate the response of the speakers with the door panel dismounted. For realistic results you need to measure in the car.
I use dual gate measurement. That means the FFT window is set to 20-200ms. Your ears do consider earlier or later reflections as not belonging to the music signal. That works really well.
The other hurdle is the out of range response of the Focal es100k ...as any other 10cm cone, the response around 1-5k is too much. After lowering the tweeters level drastically and lowering the mid drivers xo from 3k to about 1kHz, lowering the xo of the tweeter from 3k to 2kHz the target curve is now hit quite well.
This is the analogue approach:


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## RedSwede (Aug 11, 2017)

MM22000 said:


> I do not like the concept of transfering analogue signals to digital and re-transfer them to analogue. You lose quality of the signal


Whilst it is correct that in some absolute sense you do loose something from the signal, I do not agree with the first statement.

Once in the digital domain, you can have 1) far, far better crossovers - that measure acoustically what you need, and avoid all sorts of passives in the signal chain, 2) time alignment 3) EQ, 4) phase correction. Sorting out the acoustic issues of being in a tiny metal and glass box is far, far more important than possibly, potentially, loosing some audio "magic" that may or may not be there.

And also, in addition to that, using the analogue output of the OEM headunit is so, so far from this audio perfection that it renders the whole discussion moot. If you used a Helix DSP for example, you could have EQ'd analogue input for Nav or casual radio, and Toslink input for proper listening. And no need to worry about MOST - or A-> D -> A conversion, for that matter


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## MM22000 (May 21, 2021)

For this reason I did not make an absolute statement with "I don't like" 
The strongest argument for a DSP is certainly "the tiny metall/glass house". It is possible to make the analogue crossover measuring the exact required response and partly to "steer" the phase - but nothing more. 
This time I appreciate the analogue version. In a couple of years, for the next car, I will for sure use a MOST-DSP (hopefully with a fader output).


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## JVD240 (Sep 7, 2009)

Your refusal to use modern (proven) methods will deliver inferior results.

Not to mention wasted time/resources.


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## RedSwede (Aug 11, 2017)

MM22000 said:


> For this reason I did not make an absolute statement with "I don't like"


Of course you are free to not like whatever you want! Somebody can perfectly validly say "I don't like blue".

And in many areas of life I prefer to shun clinical digital techniques, for more tactful or "creative" mediums.

But car audio is not art, it's a science. It is about extracting an enjoyable sound from a ridiculous environment. You can cut up your car until nothing OEM is left. You can tweak crossover components until the end of time. But you will not achieve what you can with DSP, you will spend far more time on it, and you will spend far more money on it.

Play with analogue audio at home. Make crossovers. Make speakers, amps, bass traps, diffusion panels. Get tremendous sound from your efforts. In a car, use DSP.


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## noviceDIYer (12 mo ago)

Thanks for this thread @MM22000 ! First time stumbling upon it this week and it was super helpful. 
This thread is a must read for BMW owners who may have installed an amplifier and before installing and tuning a DSP.

Adding my experience: 
note - utilizing latest iOS BimmerCode on LCi F25 w/ base audio system & latest updates from bmw.com/update

outside of 3002, I went in & selected `HEADUNIT - 3000 HMI -> HIGH_END_AUDIO_MENUE -> volle insz` which enables 2 B&O DSP selections
Of the 2, I went with STUDIO as with my speakers, the sound is clean and not muddy and distorted. 
with 'volle insz' selected, Speed Based Volume adjustment option disappears from VOLUME SETTINGS (not sure if it's actually gone) but if it is, it may simplify DSP tuning

AUDIO_SYSTEM_VAR -> I chose 'variant3' because someone online had said that mid & high frequencies were crystal clear 
AUDIO_PROFILE -> I have 4 options (01, 02, 03, 04) instead of 2 from the original chart and I stuck with a recommendation from a MINI forum of going with 'wert_01' for a flat response
other settings: 

AUDIO_SYSTEM -> hifiAMPLIFIER_VARIANT -> external


I went looking for EQ_SETTING and EQ_VARIANT under 3000 and didn't find it; will take another look later for it
I will also go looking for AUDIO_SYSTEM_CIC, where there is something to be toggled


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## Makabra (8 mo ago)

noviceDIYer said:


> Thanks for this thread @MM22000 ! First time stumbling upon it this week and it was super helpful.
> This thread is a must read for BMW owners who may have installed an amplifier and before installing and tuning a DSP.
> 
> Adding my experience:
> ...


Do you find way to enable EQ_SETTING and EQ_VARIANT ?


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## noviceDIYer (12 mo ago)

I thought i saw somewhere it may be possible with a MOST system and I think if you have the correct AUDIO_SYSTEM you may be able to enable the EQ settings


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## Makabra (8 mo ago)

noviceDIYer said:


> I thought i saw somewhere it may be possible with a MOST system and I think if you have the correct AUDIO_SYSTEM you may be able to enable the EQ settings


I used your coding settings, and the sound is clear and better than when my coding setting was
Coding: Hifi, internal amp, audio offset on, audio var 2, audio profile 1
I was using this coding of MM22000 until I saw your post.

On your setting bass level is no longer as high and distorted as in the case of selecting amplifier internal but after recoding to amplifier external the sound level of the input signals to my AudioSystem Germany M90.4 amplifier fell and I had to tweak the gain in the amplifier to obtain the appropriate volume level, which unfortunately results in an audible increase in the noise level. But I will probably stay with this setup because it seems to be the best option. I did not measure the distortion in any way, I just follow my hearing, listening to my favorite songs so that they sound as good as possible.

If only I managed to solve the problem of the higher noise level caused by increasing the gain level in the amplifier, it would be perfect. I use this set of speakers : https://www.audio-system.de/wp-content/uploads/2021/02/MANUAL-XFIT-BMW-UNI-EVO2.pdf

And this amplifier : https://www.audio-system.de/wp-cont...0.4-M-135.2-Bedienungsanleitung-2018-12-1.pdf


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