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Audi A6 PHEV Sedan – Bang&Olufsen Premium Sound System

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@amirm maybe a new worthwhile direction for the forum? If you see better fit in a different sub forum, please move it.

This is a review of the Bang&Olufsen Premium Sound System built-in from the factory in an Audi A6 TFSIe 55 (PHEV) Sedan.

Disclaimer: Objectivity on this one is hard for me, since I was involved in the development of the car. Nothing here was not sponsored. Paid for everything myself.

Since many of you were interested in my last review of the miniDSP C-DSP (https://www.audiosciencereview.com/...udio-amplifier-review-and-measurements.33578/) and automotive sound systems have not been reviewed yet here at ASR. My train of thought was: Why don´t we test automotive sound systems with the same care, as we test home sound systems? Most people spend statistically around one hour per day in their car (in Europe, in the US even more) – why not use that time better with properly chosen sound equipment?

Overview​

00_car_overall_01.jpg


The Audi A6 is an upper-mid-market luxury sedan car positioned in the C segment. Competitors are the BMW 5 series, Mercedes-Benz E-Class, Jaguar XF, Cadillac CT5, Genesis G80 and Volvo S90. The drivetrain consist of a turbo four cylinder made into an 7-speed double clutch plus and an electric motor in the vicinity of the gearbox. Battery capacity (net) is ca. 14,4kWh, which can be charged externally via AC up to 6kW. All four wheels are driven depending on situation (“quattro”) and total power output is ca. 270kW/367 euro horsepower with 500NM of torque. Sedan body styles are not really popular at the moment, but I have to tell you that driving pleasure and comfort is so nice in comparison to so many other SUVs in this segment.

The sound system consists of 15 channels of amplification with ca. 700 Watts of power and 16 speakers which are placed in the doors, dashboard, pillars, headliner and trunk cover. Most of the speakers are not passively coupled, which allows for a good degree of freedom in the DSP tuning process. In the A-pillars two 3D speakers are placed. Fraunhofer IIS implemented the Symphoria algorithm which elevates and enhances the sound stage upwards (https://www.iis.fraunhofer.de/en/ff/amm/automotive/symphoria.html). Dolby Atmos playback is not supported yet. Audi asks for a markup of 1150,-€ for the premium B&O system in Germany. Which is a fair price considering what you get. Be aware that there is also an Advanced Bang&Olufsen sound system with 19 speakers and 1800 Watt available, which costs 6350,-€ extra.

In the car, not an awful lot badging is present, which is much appreciated.

int_badge.jpg


Measurements​

Let us start with a frequency response with the standard settings at the driver seat. All measurements were made with a miniDSP UMIK-2 (moving mic method) and miniDSP EARS.

The frequency response is sloped with ca. 1.5dB/oct. Below 150Hz we can see a relative mild bass boost (for automotive). The trough at 172Hz is a modal null point. Null points can only minimally influenced by DSP – so this is an issue that we cannot come by other than by re-shaping the car (which is obviously not an option). Other cars have the same problem. Slight resonances going above the green +-3dB tube can be found at 610Hz, 900Hz, 1020Hz, 1.8kHz and 6.8 kHz.

01_TRF_80dB.jpg


Here you can see the average of ten premium car sound systems of different makes. All of them have a trough in the region of 160-200Hz:

premium-car-sound-linearity-analysis.jpeg


The Maximum sound pressure level in the car was 103 dBC.

The step response is obviously a little messy due to the high amount of early reflections and speakers. But speakers show in general good cohesion and act as one system:

step_resp.jpg


The THD at 98 dBSPL (green) and 108 dBSPL (violet). THD is mostly created by rattling materials and trim pieces, but stays well below 7% even at loud listening:

THD.jpg


In the waterfall diagram some low frequency resonances can be spotted. But they are relatively low in level. All the cavities, tanks and spaces needed in the car make it almost impossible to have a resonance free car:

waterfall.jpg


Within the sound menu settings, a high and low frequency attenuation and boosting can be activated. They give an broadband shelving characteristic. If you want to listen to your music as flat as possible,

sound_options_HMI.jpg


sound_options.jpg


With the turn of the volume know a loudness function (that cannot be deactivated) is applied. At low levels, the low and high frequencies are boosted (thin green), while at normal levels the filter is more or less neutral (thin red and thick green), while at even higher levels, the highs are taken back.

loudness.jpg


In the HMI, a sound focus function allows an optimization for possible seating configurations. The available options are “All”, “Front” and “Rear”.

sound_options_.jpg


When seated in the front, the options “All” and “Front” work best.

sets_front.jpg


When seated in the back, the “Rear” option improves bass performance significantly, but adds a resonance at 1kHz.

sets_back.jpg

When the pure noise in the car is measured at 30, 50 and 120kmh (with a binaural miniDSP Hears + correction filter), the car is quiet, but not super quiet. At 100kmh (brown trace) the tyre resonances

driving_noise.jpg


Listening​

The listening experience is nice in the car. The staging is wide and precise. The phantom center is concentrated right above the steering wheel. Male and female vocals come through nicely. Although the system is not perfect and in no way comparable to a normal sound system at home, it is a nice treat, that you should not neglect when you can have it a new car. Bass is precise and deep but in no way rumbling and rude. High frequencies are not annoying. I can listen to the system for an hour without getting fatigued. The drop in the low mids is at 170 Hz is audible, but certainly not as bad as it looks in the measurements.

The 3D sound option is certainly very interesting, but adds too much sweetness to my taste. I do not like it, when something is tried to be added artificially.

Rating: 4.2 out of 5.
 

TonyJZX

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I appreciate the lengths and thoroughness of this. There's a few car reviewers on YT who do similar analyses of car audio like the above... but they largely do a standardised test so the graphs are directly comparable car to car.. and its vastly 2ndary in nature to the car itself.

I think almost all setups like this are 100% outsourced... a car company can go to Bose, B&O, Meridian, H/K, Levinson nee Samsung and they usually adapt a standard setup to suit your cabin... just like how they outsource seats and trim to Johnson Controls or Gates.

I'm in two minds about this. I dont spend enough time in a car any more to care about car audio. To my ears even the basic BMW business audio crap is kind of ok to me.. as long as vocals are clear and there's enough treble bass then that's ok.

I used to spend hours in a car as a network eng. who ended up as field eng. and even then I would listen to podcasts because how much music can you absorb on a 4hr+ road trip?

I think at a certain point a mid spec quasi lux Japanese or German saloon has good enough quality that the intended buyer would have little to complain about as long as they have car play or android auto. Something like an A6 would hardly disappoint anyone but I wonder just how good a $1k euro system is vs. a $6k euro system?
 
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Hi Tony -
>> I think almost all setups like this are 100% outsourced

your assumption is not correct. The work done by the brands on the sound system itself is in a lot of cases (not all!) ... rather limited.
The standard sound systems are also not bad. I will probably post a comparison between standard and premium in the near future.

>> I wonder just how good a $1k euro system is vs. a $6k euro system?
You get more speakers, more power, bigger subs, more software functions and more bling. I think everyone has to decide for themselves if it is worth it. But, in the first market, cars like these are to 95% leased and business cars. The 6k€/$ options are there to hit a certain threshold for allowances. There are job contracts which oblige you to have company of e.g. at least 85k or 95k. And in the second market options like the super sound system keep the residual value higher.
 

Juhazi

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Thank you Philipp! I haven't measured my cars, just adjsuted standard systems by ear. Drive noise is a very difficult thing to overcome, even in new upper mid cars like A6 or X3. Bass must be boosted 10-15dB and this needs subwoofers to avoid distrtion. When (if) listening when car is not running, bass is way too heavy with this setting. I have not had a car with special systems, but I've been very happy with my recent cars - Audi A6 Avant -07, BMW X3 -07, BmW X3 PHEV -00 and BMW 225xe -17.

But please save your REW captures with less pixels (900 or 1200 hor is fine) and set spl grid (y-axis) to 5dB lines showing "As plotted"!
 
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>> Drive noise is a very difficult thing to overcome, even in new upper mid cars like A6 or X3.
Definetly. Interesting thing is, that the noise predominantly coming from wind and tires. Especially tires make terrible noise.

Regarding the resolution... I have a 4k monitor. Everything else looks grainy. :)
 

Juhazi

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My guess is that most followers use laptops, pads and mobile phones!
 

anmpr1

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... but I wonder just how good a $1k euro system is vs. a $6k euro system?

Spending time on the Porsche configurator is always fun. Using your unlimited (but virtual) checking account, you pay and pay, and then expect to pay some more. But sometimes factory limited choices are sensible. For instance, with the GT3RS, Porsche wisely limits you to an optional (and relatively inexpensive) run of the mill Bose stereo. Probably no one will care about that, preferring to listen to the engine, instead.

However, the more luxo oriented Panamera (I don't even know how to pronounce that) offers the ability to upscale (to the tune of six large)--> a custom 21 speaker Burmester installation. For the price it's no doubt a satisfying choice. And by judiciously forgoing the optional leather AC vent slats and deviated leather door trim, you've almost paid for the stereo upgrade!
 
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The Porsche configurator is diabolic. :) You can spend hours configuring and falling in love with your favorite car. They are also the masters in upselling. With a 911, I could spend easily two hours checking out all the options.
 

DSJR

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But, but, but - it's an AUDI (spit) - Most new ones around here of most shapes and sizes are driven by a modern version of the 'executive repmobile' BMW 318 driver of old - hard, thrashed, too fast and little to zero consideration for other road users on our overcrowded roads. I suspect most owners will be too busy posing to really enjoy the good sounds available from thre stereo anyway ;)

I'll duck and run like hell for cover...... :)
 

Karl-Heinz Fink

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Hi Philipp,

I do the same measurements when tuning cars and the result you showed looked pretty close to the target curve I use myself. I also wave my microphone around my head, so no wonder the results are looking similar.
I'm now considering using the miniDSP microphone array solution with the 8 MEMS capsules mounted on a Dummy, so I can do the measurements without a person in the cabin. Both are ready, but I did not try them yet. Did you ever try?
Unfortunately, getting the tonal balance measured, does not tell me anything about the imaging. Adjusting the subwoofer delays can be a nightmare during the tuning (even very small differences are easy to hear), but almost no difference in the response curve.

However, I think starting a discussion is a good idea.

Best regards

Karl-Heinz
 
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Hello Karl-Heinz, good to see that my results match yours. I am using the UMIK-X and think it is extremely helpful. Especially in cars with many speakers (30+, number of speakers is the new horsepower). Crossovers, delays, side comparisons, sensitivity checks, null points, group delays, relative leveling of speaker groups, … all this can be done fast outside of the car while saving ear time. Of course with imaging the array can’t help, but your ears should be much fresher now when the array was used, all the groundwork is done. I have mounted the array on a Head acoustics HMS before, but did not really gain from that. But the customer had an easier time understanding what I was doing and it looked more impressive. —Best, Philipp
 

iulianm

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As a side note, one of the YouTube car reviewers that measure car audio systems is savagegeese.
Here's a screenshot from his RS6 measurement of B&O:
Screen Shot 2022-10-03 at 12.12.54 PM.png
 
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I wasn’t aware that savagegeese stepped up his audio game. Don’t watch his videos regularly. Last measurement I saw from him were on the Audi A8. And his approach and especially conclusions were… crude. The measurement above are better but the conclusions (crossover and placement) are still… crude.
 

PatentLawyer

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Seeing that Audi dashboard font triggers my PTSD... :) Didn't have a great experience with mine.....
 
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