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2Addicts | BMW 2-Series forum Technical Topics N20 (228i) / B46 (230i) Engine, Transmission, Exhaust, Tuning Active Sound / Symposer

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      03-11-2015, 09:19 PM   #1
SteveSFO
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Active Sound / Symposer

Anyone have documentation on how BMW Active Sound works? I know the 1 series has a device called a Symposer. Do we have it in our 2 series?
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      03-12-2015, 02:33 AM   #2
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Yes we have it, there are a couple of threads about it.
Seems to be louder when the car is in Sport mode as opposed to Comfort.
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      03-12-2015, 10:35 AM   #3
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Originally Posted by SteveSFO View Post
Anyone have documentation on how BMW Active Sound works? I know the 1 series has a device called a Symposer. Do we have it in our 2 series?


BMW Active Sound Design


Press Release: In order to be able to drive comfortably and efficiently at the same time, the developers look for solutions in acoustic lightweight construction with acoustically effective components for increasing comfort and also yielding benefits in weight and installation space through intelligent material concepts. In this way, the customer gains a functional advantage with lower weight and more pleasure for lower fuel consumption and CO2 emissions. The minimization of background noises normally requires the use of heavy insulating and dampening materials. This minimizes surface vibrations.

While the acoustic lightweight construction helps to fine-tune vehicle acoustics and increase comfort, active systems, such as Active Sound Design, ensure that the engine produces a dynamic sound during acceleration, because vehicle dynamics are an auditory phenomenon. With Active Sound Design, engineers can create the sound that best fits the vehicle character or even fulfil drivers’ individual auditory desires.
Presented in a MINI prototype for petrol engines in 2009, Active Sound Design now also helps diesel engines achieve a sporty sound that wasn’t possible for this type of engine until now. The sporty performance characteristics of modern diesel engines and their high torque, especially when starting up and accelerating, contradict the acoustic sensation of diesel vehicles. Harsh ignition impulses during combustion, which are inherent to diesel engines’ function, are responsible for their characteristic noises — commonly referred to as “knocking”. This undesirable acoustic characteristic of diesel engines has been brought to a very low level at the BMW Group through intelligent acoustic lightweight construction. This makes room for Active Sound Design, which supports a sporty sound quality. It makes outstanding driving performance audible.

In order to have a special audio experience and for a diesel vehicle to sound really sporty, sound designers have to optimally adjust the sound to the vehicle and its engine performance. Too much sound with too little engine power would make a negative impression. The engine sound must constantly provide for a harmonious driving experience. The particular challenge is allocating the right dosage of sound in all driving situations and creating an authentic audio character. An active system allows for significantly more systematic and finer adjustments than classic sound design, which is oriented on the intake or exhaust system.

The test vehicle, a BMW 635d, is sound-optimised by means of sound design and has its own very dynamic audio character. The noise typical for diesel vehicles disappears and instead, the driver hears a sporty, superior sound. The entire rpm range is accompanied by harmonious, varied and consistently appealing acoustics that make the enormous torque audible at lower rpms and also provide for fun at high rpms. Through Active Sound Design, diesel engines finally achieve the engine sound that their performance deserves.

Acoustic functional integration makes something that’s good even better. But at the BMW Group, a high degree of comfort is far from everything. A current research project of the BMW Group’s acoustic engineers concerns not only the acoustic fine-tuning of the vehicle, but also enhancing the driving experience through Active Sound Design.

Diesel engines present a special acoustic challenge with regard to background noises and audible dynamics. The combustion process in a diesel engine is not as homogeneous as in a petrol engine. The ignition sequences in the combustion chamber are more intense and louder. This is transferred to the adjacent parts and emanates into the surroundings and causes the “knocking” sound that is typical of diesel engines and inherent in their design. Due to the harsher firing pulses, a diesel engine is considered more unpleasant to the ear than a petrol engine.

In order to compensate for these acoustic disadvantages, dampening could be increased. However, use of heavy materials on the engine housing negates the benefits to efficiency of the lightweight aluminum engine block. Acoustic engineers demonstrate how to make an efficient diesel engine still sound comfortable and even dynamic through acoustic lightweight construction in combination with Active Sound Design.

Although the acoustic lightweight construction helps increase vehicle comfort and efficiency, engineers at BMW always carefully ensure a special driving experience as well. After all, the brand name stands for “driving pleasure”. Since insulation makes the engine’s operation less perceptible, this first of all means a “loss in sound” and a drop in discernible driving dynamics. As tests show, besides physically measurable longitudinal and lateral acceleration, the sound of acceleration also makes a decisive contribution to the sensation of driving dynamics.

With the use of active systems for sound design, engineers can actively shape and optimize interior sound and thus systematically influence “heard” dynamics. In order to produce the desired sound patterns, the natural sound of the engine is intelligently refined with an electro-acoustic system. A digital signal processor interactively generates additional sound components based on constantly updated driving data so that a harmonious overall impression is formed. Initial research projects have already shown how effective that is. In a MINI prototype presented in 2009, a four-cylinder engine can be made to sound like a powerful V8 engine or superior straight-six engine. Besides the fun factor presented by individualization, Active Sound Design also has very serious applications, such as helping diesel engines attain even sportier sound characteristics.

An experiment demonstrated what potential this has. The BMW engineers took two identical vehicles and adjusted one of them using sound design such that the sporty qualities of the engine were clearly audible. Subsequent test drives showed that test persons, despite measurably identical longitudinal dynamics, judged the driving performance of the vehicle with integrated Active Sound Design to be better. The subjective in-vehicle impression was comparable to the sensation of an accelerating car with a stronger engine. This means more fun while driving with identical driving behaviour and equivalent fuel consumption.

The augmented dynamic experience should now benefit drivers of diesel vehicles as well. While diesel engines are highly efficient, in acoustic terms they aren’t considered the epitome of dynamics and driving pleasure. And that is although a modern diesel engine has very sporty performance characteristics and is measurably superior to comparable petrol engines thanks to its high torque at starting and acceleration.

Diesel engines’ harsher firing pulses during combustion, which are inherent to their functionality, are responsible for the characteristic sound. This undesirable acoustic characteristic of diesel engines has been brought to a very low level through intelligent acoustic lightweight construction. This makes room for Active Sound Design, which supports a sporty sound quality. In this way even objective aspects of driving performance are able to be heard.

Today’s diesel engines are capable of a lot. They’re efficient, highly effective and high-torque, but until now they were lacking the right sound. With Active Sound Design, they’re finally achieving the sound that they deserve based on their performance characteristics.

In order to produce a special audio experience and allow a diesel engine to sound as sporty as it feels, the sound designers optimally adapt the sound to the vehicle and its engine performance with great attention to detail. Too much sound with too little engine performance is just as undesirable as minimal time delays, because the human ear is very precise. The engine sound must constantly provide for a harmonious driving experience. The particular challenge here is allocating the right dosage of sound in all driving situations and creating an authentic character.

Active Sound Design allows for significantly more systematic and finer adjustments than classic sound design, which is oriented around the intake and exhaust systems. “Even minimal changes to vehicle sound can have a big impact, since human hearing subconsciously evaluates acoustic surroundings like a high-performance analyser and all changes are continuously registered in the brain.” Through their know-how and experience, the BMW Group’s sound experts know exactly what sound properties must be changed to attain the desired result. At the BMW Group, specialists from Sound Design and Psychoacoustics cooperate closely with the engineers from Engine Development. With a clear idea of a sporty diesel sound, they’ve created an entirely new and impressive audio character for a sport coupé with a diesel engine.

The sound-optimized test vehicle, based on the BMW 635d, has its own very dynamic audio character. The noise typical for diesel vehicles is eliminated and instead, the driver hears a very sporty, superior sound. The entire rpm range is accompanied by harmonious, varied and ever-appealing acoustics that make the high torque audible at lower rpms and also provide for fun at high rpms. Active Sound Design emphasizes the existing driving dynamics of the engine and makes them immediately audible and tangible.

A team of physicists, engineers, sound designers and psychologists are working on Active Sound Design. Although they employ electronic tools and machines from analysis to simulation and test drives, end the human ear is the ultimate measure.

Through the combination of measures for acoustic lightweight construction with Active Sound Design, the customer experiences a completely new vehicle sound and can enjoy the benefits of a modern diesel engine’s dynamics and efficiency even more. The noise level remains low at constant driving speed, such as during a long trip. The driver only hears gentle rolling and wind noises. In dynamic driving segments, like acceleration, the engine emerges from the background and demonstrates its performance to the driver. The driver experiences driving dynamics with all senses, along with increased driving pleasure.

See also: http://www.washingtonpost.com/busine...cb4_story.html
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      07-01-2015, 05:06 PM   #4
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Is there a simple way to turn this off? Unplug something, perhaps?

I love exhaust sounds, but dislike the pumped in fake sound.
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      07-01-2015, 07:52 PM   #5
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Quote:
Originally Posted by NEUE02 View Post
Is there a simple way to turn this off? Unplug something, perhaps?

I love exhaust sounds, but dislike the pumped in fake sound.
You need to do some coding but yes, it can be turned off.
Look at the coding threads ("F22 coding cheat sheet", etc.), you need a $20 cable and some software.
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      07-14-2015, 10:22 AM   #6
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You can get the BMS can flap to disable active sound

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      07-14-2015, 02:07 PM   #7
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I've had mine off for a couple of days and the difference is amazing...they really pump in the sound.
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