BMW Audio Upgrades

A quality car deserves a quality audio upgrade

BMW Audio Upgrades


Even Germany Hates The BMW Sound!


BMW is the number one car when it comes to owners asking for audio upgrades. We may have mentioned this before but it is not only the UK audience who crave better sound in their Beemers – we look at two German brands and what they offer to hapless owners of the ultimate distortion machine!


Try as they might, it just seems to be beyond BMW to understand what is required to create good sound in their cars. They have tried every major badge under the sun but still customers complain about the flat, podgy mess that comes out of the speakers in their cars. In fact their complete incompetence in this area has spawned an industry in its homeland.


Regular readers will be aware of German manufacturer, Rainbow. They have been around since the early eighties and committed their development effort to correcting sound in all sorts of vehicles not just BMWs. We have previously expressed extreme pleasure with what they do, particularly with their replacement BMW speaker programme. The issues thrown up by the vehicle are many and varied and show a complete lack of care for customer’s ears. One such area is the under-seat woofer. Fitted to many models, the cheap and nasty factory offering is squashed into a plastic shell and plays full range audio straight towards the drivers bottom. The main issue here is one of tuning (not to mention anatomy!). Bass is far less directional than treble and so there is a scientific basis for BMW’s decision however the implementation is very flawed indeed. In part this is due to the enclosure itself but blame can also be placed at the door of the manufacturer of the actual speakers. Rainbow’s strategy was to create a woofer that allowed installers to drop the frequencies sent to the under-seat woofer much lower in frequency and give the mid-range speakers (often mounted directly behind the door armrest) more work to do. The under-seat woofers are given a higher power rating consistent with the immutable fact that bass requires more power. The result, provided the horrible mid-range and tweeters are replaced, is to re-establish a stereo image underpinned by warm, powerful lows that give the high-end more space to “breathe”. Rainbow’s solution, snappily named ‘BMW E&F Series Seat Woofer’, is a triumph given the challenges presented. In order to replace the standard fit woofer, one of equal depth had to be developed. However, this needed to be able to move much more air than the factory offering. It is generally accepted that to move more air, either the excursion (distance the cone moves) or the cone area need to be increased. Changing the physical size was not an option and so a great deal of work went into increasing excursion.


Rainbow had an even easier job in developing mid-range and tweeters for BMW vehicles, as the originals are not very good at all. In terms of construction, from a quick glance the Rainbow Intelligence Line looks similar to the factory fitted speakers, but it is the technology under the skin and the materials chosen that make the Rainbow replacements chalk to the original factory fit cheese (I think speakers made of cheese would actually sound better!). Favouring a silk-domed tweeter, Rainbow is famous for delivering speakers with high-end warmth rather than ear-splitting harshness and integrating the high frequencies seamlessly with mid-range. BMW seem to approach this critical area by removing mid-range altogether which although passing the showroom 30 second test will not please once the car is on the road. I have heard many Rainbow Intelligence Line-equipped BMWs and been demonstrated original equipment by proud owners of these cars and you can take it from me, you do not need special ears to hear that the Rainbow replacements offer huge improvement. I would add however, that a little extra power will also make a huge difference and would always recommend a little boost with a relevant amplifier and don't forget the sound treatment!


Another German manufacturer, Eton, has a similar heritage and has also long been on the hunt for plug and play solutions to help owners of BMW and other awful sounding cars get some decent audio in their lives. In Eton’s case a whole sub-brand has been created called UPGRADE Audio. I am new to this brand and was initially, somewhat sceptical as I already had an internal warmth for Rainbow products. My initial impression even just looking at pictures of their products is that UPGRADE Audio is like supercharged Rainbow. Add to this the slightly higher build/material quality and the fact that in their case, plug and play really does do what it says on the can. All products carry either flying leads with appropriate vehicle-specific connectors fitted or have the connector actually mounted on the speaker chassis. This would suggest that a generally higher retail price is offset in part by reduced installation time.


Once again, UPGRADE favours a silk-domed tweeter and with a musical heritage such as that enjoyed by Germany, who would argue with that. The woofers carry a characteristic “rib” effect on the impregnated pressed paper cones that have been developed specifically to help with rigidity as well as sound dispersion. This is incredibly important in a car as factory mounting positions are never ideal and mostly downright awful. It is clear from the magnet size that UPGRADE speakers have been designed to run from a suitable amplifier.  A generous rolled surround further suggests long excursions for moving more air. The coaxial speakers in the range seem to feature the same 25mm silk dome tweeter that the component systems use which shows a commitment to sonic purity over price that is most refreshing.


Baskets are constructed from glass-fibre-reinforced polycarbonate for mechanical stability and feature mounting lugs rather than a flange for mounting. This makes one-for-one replacement extremely easy especially when added to the aforementioned on-board connectors.

At time of writing I haven’t had the opportunity to listen to UPGRADE products but I have spoken to a few who have and they have nothing but good things to say. Car audio installers can be a cynical lot but I have spoken to three and they were all extremely enthused by the price to performance ratio, which I know FOUR MASTERS hold very close to their hearts.

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