Improving the sound of the new car!

This presentation features a BMW M5 with a F90 body kit, aged a couple of years. A supercar tuned to produce almost 800 horsepower roars with great force as the accelerator is moved in a direction perpendicular to the floor. Although the soundscape is already incredible in itself, the comfort of the ride needs the roar of the exhaust system in addition to the noise of the road.
high-quality sound.

Text and photos: Janne Soilakari

The set originally came from Bowers & Wilkins, a company known from the home cinema sector – but also for producing premium sound systems for cars – and has a price of about 7,000 euros when adding new car accessories, so expectations are high and they should be kept high.

”The amplifier worked well in the midbass range, but the treble and midrange were a big disappointment. The sound was muddy and you couldn’t listen to it for long, not even at a higher volume,” says a car owner who is otherwise interested in audio.

The change was based on AI-Sonic loudspeakers featuring domestic design elements, from which we found small S3 T22 treble drivers, as well as the four-cone S2 4BMW midbass drivers and the cone-shaped BMW-SW8 bass units that go directly to their original locations. A separate subwoofer has not yet been added to the system, as the reproduction of the midbass units housed under the front seats reaches surprisingly low levels.

The amplifier and processor for the set’s speaker elements are specifically the 7-channel Match UP 7BMW designed for Bemar cars. According to the car owner, it has a warm sound across the channels and is sufficient in power for normal listening in the front seats. Comprehensive adjustments via channel-specific frequency correction and delay allow for the full potential of the set to be fully utilized, and in part also help to compensate for the limitations of the original installation locations. Installation of the device is basically done using the included wiring harnesses via plug & play principle. As a plus point, this amplifier has the option for a line output, meaning that if hunger strikes, you can connect a small monopole subwoofer to control it.

One-day installation job
”In installing the amplifier, you first have to remove the floor panel of the cargo compartment, which is easily removed by lifting it. After that, the plastic panel that is held in place with four screws is removed, and one torx screw is removed from the side bracket. This allows the amplifier to be removed. The wiring harness that came with the original amplifier is disconnected, and a Match wiring adapter is attached to it, which allows the new amplifier to be connected. This is done completely plug & play, and it takes only about half an hour at most,” says the car owner.

If you want to get it really easy, then after this you run the auto-model-specific settings through USB to the amplifier’s signal processor, and that’s clear. According to what I’ve heard, the difference with the vintage model is already surprisingly clear even on B&W’s own speakers. In this project, however, we ended up replacing all the speaker elements and making the DSP settings ourselves.

Clearer sound with new elements
The speaker placement in Bemar’s cockpit doesn’t seem particularly optimal at first glance. The tweeters are located in the appropriate places in the mirrored panes, but the midbass is placed almost in the middle of the door and the subwoofer is located under the front seats. However, the owner of our test car is not driving a BMW for the first time, so we found out that the speaker placement actually works quite comfortably. Therefore, the reason for the sound problems lies more in the speaker positioning than in the actual sound quality.

The AI-Sonic S3 T22 models ended up as the new treble elements; these are universal 22mm silk treble elements. Although they are not exactly tailor-made elements for this car model, they reportedly settled in place without causing major head-scratching. The small physical size of the elements was very helpful in this regard.

The four-chamber AI-Sonic S2 4BMW models became the center-channel elements. Installing them required removing the door panels, which wasn’t as difficult as one might think at first glance. No additional sound absorbers were added to the doors during the element replacement, as the first thing that was wanted was to test how the system works without them. Later, a small amount of sound absorption has indeed been added, but the car owner says that its importance in this set was still significantly less than usual:

”The low-center area gained a bit more composure with the damping, so it wasn’t a waste. But the air was pretty good too,” the owner describes.

The Kasitom AI-Sonic BMW-SW8 elements were replaced under the front seats with original midbass speakers. The midbass enclosures were lightly damped with a cld-damping mat and with absorbent material in small sections, but otherwise the installation is similar to the original:

”I’ve tested with the previous car to fill the enclosures completely with wax and the like, but that doesn’t work. The power and punch of the midbass sound suffer, and the separation also gets worse,” says the man.

The midbass enclosure is basically quite small in terms of volume, so reducing it even further is not recommended.

Sounds in the punch
Overall, the sound quality of the set is quite excellent for the price of the upgrade. We don’t really know what the original B&W system sounded like, but according to the car owner, the sound is now at a completely different level compared to that. Since this is a long-time audio enthusiast, there’s no reason to doubt this view.

The sound is dynamic and precise. The mid-range is clear, but there is a slight sharpness in the treble section, which can be reduced by focusing on the controls even more thoroughly. The bass range has exceptionally strong power. It’s not really necessary for the subwoofer either in normal listening; the playback is actually quite low.

The price of the whole thing without the programming source is under 1,500 euros, which is in a way even ridiculously cheap, especially when compared to the automakers' own, often really overpriced premium sound systems.

We can recommend it, a worthwhile upgrade!

The article has been published In the issue of AVPlus magazine 6/2020 (No. 199)