BMW M135i 2012

BMW M135i S676 HiFi Speaker System Upgrade

A medium-range sound system from BMW – S676 HiFi is also the one that is the easiest to upgrade. For this purpose, we use a solution that has been developed and produced in Germany by Audiotec Fischer, the worldā€™s leading car-audio manufacturer.

Original Setup:

BMW S676 HiFi factory amplifier,
3-way splits in the front: 1″ tweeter, 4″ midrange, 8″ underseat woofer,
Coaxial speakers in the back – 4″

Mediocre sound quality, not enough bass, low volume output

New Setup:

MATCH UP 7BMW – PnP DSP amplifier
STEG BZ 40D – rear coaxial high-end speakers
Audison drop-in underseat subwoofer

Michael came to us with the request to upgrade his vehicle because he wasn’t happy with the stock setup at all – muddy sound and the lack of bass as we know it from most OEM systems. He had the front speakers replaced with Focals, although very precise high-end components, they were too sharp in high tones and not too pleasant to listen.

We installed new Audison subwoofers (client’s gear) along with some sound deadening material and the rear speakers were replaced for hand made Italian high-end coaxials STEG producing a softer warmer sound.

The heart of the whole new system – MATCH UP 7BMW DSP has replaced the OEM amplifier. This DSP from Audiotec Fischer is a super HQ piece of technology holding multiple EISA awards.

Installation done, sound tuning starts. That is also what played the most important role in the whole sound upgrade. There were significant peaks in the front speakers’ frequency response all successfully dialled down making the music far more pleasant and natural. Not as much had to be done for the STEGS at the back.

Subs were tuned to the point of no distortion across the whole volume spectrum yet playing at their maximal potential without overpowering other frequencies. We offer several more brands for the BMW under seat subwoofers, check more here.

All parts we used have been made to fit BMW so there was no need for any modifications other than undoing a few bolts and putting them all back.

After replacing the gear and tuning the system, we spent another hour in the car sitting next to the client fine-tuning the music to his own taste.

For more, check our current package deal for BMW S676 HiFi Speaker System Upgrade.


This setup is suitable for all BMW models with the S676 HiFi system, all up to the year 2019. Please contact us to check the compatibility with your vehicle.


Dynamic sound, clear tones and a great bass frequency response.

The stage has been precisely tuned up with the sound image oriented for the driver’s seat. That way it’s a much more enjoyable experience to drive the car around.

Installation time: 1 day
Total cost: $2690

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Installation Photos

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