Why Upgrade your BMW's Amplifier?

Bart Donda
Apr 23, 2021

The perfect BMW sound system upgrade is not only limited to adding or replacing speakers or mounting a subwoofer in your trunk. If you are looking for a louder, cleaner/clearer and more accurate sound, an amplifier is simply a MUST.

Why Upgrade your BMW's Amplifier?

What is an amplifier and how does it work?

The purpose of an amplifier is to amplify a low voltage signal (line level signal) to a high level signal suitable for “driving” a speaker or speaker set. Needless to say, a more powerful amplifier will have an easier time driving speakers with clean, distortion free power, ensuring loud and clear reproduction of your favorite music. Depending on the factory audio system in your BMW or MINI, you’ll have more or less amplifier channels powering speakers of different quality and power.

What is an amplifier channel?

A channel in an amplifier is a single audio output stage. In BMW car audio, even in a Base stereo system (where there is no dedicated amplifier) your head unit has 4 amplifier channels built into it which directly drive the speakers.

In a HiFi system the head unit also has 4 audio outputs, but instead of driving speakers directly, these outputs are configured to supply the dedicated multi-channel amplifier with a suitable low voltage line level signal. At this point, the amplifier takes over the duty of increasing the audio signal amplitude, and it’s passed on to a specific speaker e.g. a woofer or a speaker set like a midrange+tweeter.

There are many more differences between various BMW audio systems, so we’ll go over the key points to give you a better understanding of their set-up and features.

Do all BMWs have dedicated amplifiers?

No, not all of them. Whether your car is equipped from the factory with a dedicated amplifier or not depends on your BMW sound system. There are 4 common audio options:

  • Base (Stereo) – the lowest-level BMW sound system, unavailable in the US and Canada. It is powered by the 4 amplifier channels built into the iDrive head unit and doesn’t have an additional amplifier. This means the few speakers present in Base stereo BMWs and MINIs are driven only by the built in output stages of the head unit. This system overall leaves a lot to be desired.  
  • Hi-Fi (S676A) – an option one level above the Base system. Hi-Fi equipped vehicles come with an 8-channel amplifier where only 7 of the 8 channels are used to drive speakers. There is no graphic equalizer in the iDrive system of HiFi equipped vehicles, however the fact that they have a dedicated amplifier combined with decent speakers results in an overall good quality performance.  Owners of HiFi option cars can greatly benefit from upgrading their factory amplifier with our Premium Audio System. Thanks to its DSP processing and abundance of power reserves, we can EQ the factory speakers to a smoother frequency response and optimized stereo imaging, which easily makes listening much more pleasant.
  • Harman Kardon (S674A) – a small step above the Hi-Fi (S676A) audio system. It features an amplifier which is nearly identical to the HiFi one, with the same number of channels, but has a different set of speakers with Harman Kardon branding. This option is present in vehicles with space constraints, such as MINIs, 2 Series BMWs or i3s, and it too can be upgraded just like the Hi-Fi system.
  • Harman Kardon (S688A) and Hi-Fi System Professional (S677A) – the upper-tier BMW audio systems. They contain 10-channel amplifiers connected to the head unit with fiber optic cable. Similarly to the Hi-Fi system, only 9 of the 10 channels are used. The amplifier used in these systems has plenty of power, and a lot of speakers located all around the car as far as the eye can see.

If you’re not sure which BMW sound system you have, decode your VIN and we’ll send you the full vehicle specification list.


BMW Amplifier upgrade 

What about our BimmerTech amp? The Premium Audio System has 9 channels: 8 speaker level channels and 1 RCA line level output (this one can come in handy for connecting an additional subwoofer in a trunk should you feel like having one). Inside our amplifier designed for BMWs and MINIs the analog audio signal from the head unit gets converted into a digital one, processed and converted back to analog before being amplified and going to your speakers. The biggest advantage of our amplifier is the fact that we pre-set all kinds of advanced settings such as delay, crossovers, and EQ to dial in the sound to match your exact musical taste. Prefer stronger bass? Maybe more pronounced vocals? No problem. Such tuning requires expert knowledge, and a bit of measurement equipment and (or a good pair of ears ear). Fortunately, if you’re not experienced, we’ve saved you the trouble and offer the BimmerTech Premium Amplifier pre-loaded with a custom tuning file into its 64-bit fully adjustable DSP to give you the most from your OEM or Alpha One speakers. 

That’s why getting a Premium Audio System will be especially beneficial for you if your sound system lacks an amp (such as Base), or features a BMW amplifier (like Hi-Fi) which still doesn’t have any advanced DSP or as much power as our amp does.  If you combine it with our refined midranges, tweeters, beefy woofers, and a matching tune, your sound will be drastically improved. And by that we mean – a lot punchier, powerful, low reaching and detailed in its mid and high frequencies.

Furthermore, regardless if you’re upgrading from a Base, HiFi or Harman (S674A) system - with our amplifier, not only will each speaker or speaker pair have its own dedicated amplifier output channel, but also a dedicated DSP channel, thanks to which we can mold the sound of each output channel exactly the way we want it to sound. This is something OEM amplifiers can’t do, not even the Harman or B&O systems, because while they do have a graphic equalizer - it can’t be adjusted separately for each channel.

How much power do you really need in a BMW amplifier?

It’s very common to boast about power figures as if they are the be-all and end-all determining factor of any audio upgrade. In reality that’s not the case, not even close. But, power can’t be discounted, that's for sure.

BMW amplifier

From a technical standpoint you need clean, distortion-free power. Simply, the power capability of the amplifier needs to be able to exceed what the speakers can handle at max volume on the dial, without the amplifier ever needing to get anywhere close to its max rated specs. This means that even when you have the iDrive volume cranked “all the way up”, the amplifier should still have ample output power reserves. 

BimmerTech’s amplifier exceeds these requirements by a large margin, as it can output about double the power that Base or Hifi BMW speakers can handle without ever breaking a sweat. Same with our Alpha Ones. Thanks to this, our amp sounds equally well at low playback volumes as it does at full volume, without any compression or distortion. 

Importantly, when talking about power it’s pretty common for manufacturers and vendors to hype up the specs of their equipment by quoting power levels at ridiculously high distortion levels. However, such practices may be not only silly but also misleading. Especially when you connect an amplifier to a factory wiring harness that can only supply so much current to an amplifier before blowing a fuse. What you really need is an amplifier which has more than enough power at all times of normal use, without ever needing to push anywhere near the limits of what it’s capable of.

What is a DSP in a car audio amplifier?

The Digital Signal Processor (DSP) is a chip which processes audio signals in the digital domain. You may ask how is this possible? The analog audio signal arriving from the iDrive head unit first gets converted from analog to digital, then enters the processor which does whatever it was programmed to do (thanks to the tuning file loaded to it), and once again the digital signal gets converted back to analog, before being passed on to the amplifier section. 

What makes a good DSP?

A lot of audio equipment have digital processors these days but three things are crucial when in comes to DSP:

  • The fact that a piece of equipment has DSP doesn’t mean that the specific processor is good. DSPs differ greatly in their processing power just as it is in the case of computer processors.
  • Even if the processor is a state of the art, top of the line design, in reality it’s only worth anything if it has great software to go with it.
  • A powerful processor combined with great software still isn’t worth a whole lot without someone that knows how to program it correctly and masterfully. Using a metaphor – owning a $10.000.000 recording studio with all the rooms, equipment, instruments and software money can buy, will not make you a record selling artist or even an artist that anyone would care listening to, record sales aside; if you’re not a good musician, great equipment alone will not do much for you. Similarly with a DSP car audio amplifier – it’s the combination of hardware, software and someone that really knows and cares about what they’re doing to reap all of the benefits of having a DSP equipped amplifier.

When it comes to the Premium Audio System, not only is the DSP embedded within our state of the art amplifier, but it also has some very advanced tuning software to go with it, thanks to which it can be set up to perfection by the right pair of hands and ears. 

Because we set up the DSP for you, you don’t have to understand a single bit about making it sound great while being safe for your speakers. Ever since releasing the Premium Audio System, we’ve been pre-loading our amplifiers before shipping with an appropriate, optimized tuning file based on your vehicle's VIN, which we always have to know to deliver an amplifier to you.

What exactly is this tuning file? A tuning file as we call it is a small file which gets loaded to the amplifier from a laptop via a USB cable. It contains all of the various settings for the DSP which mold/adjust the sound that is coming out of your car's speakers to be as pleasant as possible, within the limits of what the speakers can handle.

How to adjust BMW amplifier settings?

Our advice – leave this job to the experts ;) Unless you’re a skilled audio specialist, it’s best for you to hand any adjustments over to professionals who are fluent in tweaking the amplifier settings. Even though BimmerTech’s baseline tuning files are already expertly optimized, we’re always more than happy to hear your needs and perfect the sound further.

As they say: variety is the spice of life, and the best possible tuning file will be different depending on the genre you listen to. The tunes will vary for someone that listens exclusively to modern, overly compressed music that was mastered to sound loud and catchy, compared to less compressed classical or instrumental music with a high dynamic range, where there is an actual differentiation in volume levels between different instruments over the period of the song. 

For this simple reason a ‘one size fits all approach’ is never going to cut it, and tuning adjustments are almost inevitable.

Keeping the above in mind, we already prepared different versions of tuning files for different BMW chassis, since the same tune would sound nowhere near as good in a 2-Series as it would in an X5. But more importantly, we always make sure to tweak the tunes based on the music you're listening to and the way you like listening to it.

How to adjust BMW amplifier settings

How to choose a car stereo amplifier?

The key word here: VIN.

Before you lay your hands on any BMW audio system upgrade, you have to check which system your car is equipped with. Enter your VIN on this website and you’ll be shown a kit you’re compatible with, as well as your current audio package.

We’ve got tuning files for every BMW chassis, so no worries – you won’t be left out of audio personalization.


We recommend that you also read this article about BMW amplifier and speaker upgrades.  You will find out when you should do just the speaker upgrade and when it is crucial for your BMW to get some powerful audio with an amplifier upgrade.

How to install an amplifier in your BMW?

We made the amplifier upgrade one of the quickest and easiest upgrades you can do. Unless you have the most basic audio option in your BMW, installation takes no longer than an hour and doesn’t require any advanced technical knowledge. It will take longer if you have the Base option since it requires a complete installation of an amplifier and harness and not only replacing it. This makes it a perfect choice if you want to upgrade your audio without the extra hassle that comes with replacing your speakers.

See how to install a MINI Cooper amplifier or an amplifier for BMW F30.

Prior to installation, you should plan the wire routing to avoid any possible damage to the wire harness. The cabling should be protected against possible crushing or pinching hazards. Also, avoid routing cables close to potential noise sources or high power accessories. Once you order your audio system upgrade at BimmerTech, you will get detailed instructions for your vehicle.

To help you with a DIY install even more, we’ve created a complete kit of DIY essentials that includes every tool you need for a smooth upgrade process. Among others you’ll find there: screwdriver bits, wrench bits, a 1/4" bit adapter, a 4" extension bar and more.

Check the installation video we made for you:

Don’t have time to get your hands into a DIY project? Our installers can do the job for you! Check the nearest one

Why choose the BimmerTech amplifier? 

You won’t find any other company out there that knows BMW’s electronics systems to the extent that our team at BimmerTech does. We’ve been finding ways to squeeze the most out of your BMWs for years. Apart from a fleet of various model R&D cars that stand in our offices’ parking lot, we’ve got racks of iDrive head units on our shelves always ready to be installed, tested and optimized for every existing BMW audio system to the limit.

Thanks to the fact that we eat, sleep, own and dream about BMW, day in day out, we simply know what your BMW needs through and through. When you combine that experience and knowledge with our proprietary VIN decoding tools, based on which we make recommendations – we can guarantee you’re in safe hands.

As you can see, when it comes to amplifiers, plenty of clean power combined with state of the art DSP processors and masterfully adjusted tunes are the fundamentals of a great audio amplifier upgrade.

To seal things off, you can take note of the fact that we’ve been offering our Premium Audio System for over 5 years now. It was used, tested and verified by thousands of BMW owners, who till this very day feel it hasn’t aged one bit. Many of our customers have been moving their amplifier from one BMW to the next, changing only a bracket or harness, keeping their BMW’s audio systems on the cutting edge throughout the years. This trend is going to continue. We have been supporting it to work flawlessly in 3 generations of BMW, spanning from E-Series chassis cars (some of which are already becoming collectables), through the modern F-Series cars, all the way up to early G-Series models. And, that’s not our last word, as the new BMWs equipped with  iDrive 7.0 will soon also be compatible with our amp. We’re pretty sure you could call that a tried and tested, timeless design – considering today's standards of consumer electronics becoming obsolete every season.


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