Scroll down below to read our blog, which will inform you about the best practices for upgrading the audio on the AUDI A4
(2005 – 2008) Model B7

AUDI A4 B7 (2005-2008)



The Audi A4 is a good compact sedan for a premium audio upgrade. The car has a total of between 9 to 16 speaker slots (depending on variant) which are evenly distributed and staged high up on the dashboard, mainly in front to give the driver and co-passenger a rich and clear music experience. The 16 speaker, Bang and Olufsen OE audio setup on the top end A4 comes packed with rich features like ‘3D-Sound’ and ‘Acoustic Lensing’ which mimic a virtual surround sound. Being positioned in appropriate slots and tuned to deliver crisp and clear audio response to the cabin occupants. Though this audio setup sounds quite balanced, it lacks head room at higher volumes. The B&O audio setup is a good benchmark to match or to improve upon in case of an audio upgrade on a Bose audio A4 variant.

The Bose setup’s basic built speakers in the non-B&O premium variants do sound good to passive listeners. But, just does not work for anyone who is used to a higher level of sound quality at home or in another one of their premium cars.
AUDI have installed large 6.5” speakers in the front doors in such a way that brings good lows (bass) right up front in the A4. There is an 8” Subwoofer (Bass driver) installed on the rear parcel tray to add lower frequencies, also creating a roomy feel for the bass reproduced in cabin. The problem actually lies in the actual build of the speakers and OE amplifier, which are purpose built and are meant to sound average to the experienced listener.  This could be a strategy to push audio lovers to their costlier B&O sound variant.

Standard Speaker slots / locations of equipment in Non-B&O variants:

8 speakers in 4 doors, 1 subwoofer (bass driver) on the real parcel shelf and a center channel speaker up front in the dash board. These variants come with an amplifier which powers all the speakers in the car and is located on the left side in the car’s boot.

Standard Speaker slots / locations of equipment in B&O variants:

8 speakers in 4 doors, 4 speakers in the dashboard (Center channel speaker and tweeter along with 2 mid-range drivers), 4 tweeters (high frequency drivers) on the front A pillars, 2 speakers and 1 subwoofer (bass driver) on the rear parcel shelf. These variants come with an amplifier which powers all the speakers in the car and is located on the left side in the car’s boot.


Due to the compact build and overall cabin volume, the A4 does not need very powerful speakers in order to produce a clear and balanced music experience. The doors are built quite strong and often sealed off with a plastic cladding or aluminum cladding which produces strong bass response compared to some of the other cars in the same category. On the Bang & Olufsen variants speakers are placed in locations to create a 3D surround effect. In order to get the right amount of detail, placement of speakers and especially tweeters is very vital in any car. The B&O variants are acoustically very good compared to the Non-B&O variants.


Almost all AUDI cars suffer plastic creaking and degradation on Indian roads due to the poor condition of the road surfaces, pockmarked with pot holes and ridges. Though this problem can be addressed with damping and soundproofing, some minor creaks here and there crop up in some AUDIs. The rear parcel shelf inside which the factory fitted subwoofer is mounted, jarrs at higher volumes, though it can be rectified with some damping and sound proofing.


Full Upgrade on Non-B&O Variants:

The cleanest method of upgrading the audio on any premium car is to follow the least invasive wiring method. The right way of upgrading the audio on the non-B&O variants is to start with configuring an aftermarket sound processor / signal processor connected to the AUDI MMI acting as the master controller for the rest of the equipment to be added.  The next step is to select set of speakers and matching amplifier(s) staying well within the provided space in the car, which in case of an A4 is a medium amount of clearance. The final speaker configuration is a front 2Way or 3Way setup (Mid-range speakers and Mid-bass speakers in doors, tweeters in the A pillars) and Rear 2Way (Tweeter and Mid-range speakers in doors) speaker setup.  An 8” Subwoofer replacement is to be placed in the stock location in the rear parcel tray or a Subwoofer in an enclosure in the boot for a deeper and more powerful bass response. All of this has to be powered by amplifier(s) with matching power and sound signatures.

“ Some Tech Gyaan-
A Digital Signal Processor sums up the signals from the Audi Main Entertainment Unit to flatten the input signal to provide a clean and controlled output signal to the aftermarket amplifier(s) to reproduce a very clear audio experience in cabin. “

Partial Upgrade on Bang & Olufsen Variants:

Now, this variant of the A4 already has a good sounding setup and upgrades are usually partial. What is needed is a compatible pre-amp unit which will allow the existing B&O amp to operate seamlessly with the aftermarket equipment we plan to add. Tuning and Room / Cabin analysis has to be performed extensively to recognize the points at which the Frequency responses have to match and merge. The installation is very similar to the Non-B&O variants, but the analysis and tuning of the audio takes some time and patience in order to achieve a perfect balanced sound.

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