Harman Kardon vs Hi-Fi vs Aftermarket Upgrade for BMW

Bart Donda
Oct 20, 2020

Wondering what the difference is between all the audio options and speakers for BMW? Don’t worry, we’ve explained everything you need to know right here. It’s important to keep in mind that with all the different models available, there may be minor exceptions to the information you’ll find in this post. For example, in a BMW F30, Harman Kardon might mean a different number of speakers than are part of the Harman Kardon speaker system in another model.

Harman Kardon vs Hi-Fi vs Aftermarket Upgrade for BMW

We’ve compared the three standard factory BMW sound system options alongside the Bang & Olufsen system, and BimmerTech’s Premium Audio System and Alpha One speaker and amplifier upgrades, in case you’re considering getting aftermarket BMW replacement speakers and want to know how to replace BMW sound system.


You can check which system you have by going on a free BMW VIN decoder tool and finding your audio option in the list of vehicle options. Relevant option codes to look out for are S674A, S676A, S677A, S688A, S6F1A, S6F2A and S752A.

BMW Speakers Upgrade

BMW speaker placement. Please note: The base and Hi-Fi options will not have the full amount (16). The base system does not include an amplifier.

Base (stereo)

Audio option: N/A

The base system, as the name suggests, is the most basic audio option for BMWs. In some countries (for example the US and Canada) it’s not even available and is replaced by the HiFi system as the standard option. That should be evidence enough that even casual music fans would be best advised to steer clear of this option.

Equalizer settings here are very limited, with the only options available being:

  • Bass/treble
  • Front/back
  • Left/right

It’s usually composed of 4 mid-range speakers and 2 underseat woofers. Tweeters are nowhere to be found here (which can be observed by the missing mesh tweeter grilles inboard of the side mirrors), resulting in music that will likely sound dull.

There is no dedicated amplifier either; instead, the head unit itself is responsible for the amplification, further reducing audio quality and maximum audio output. This may result in a lack of sufficient volume, and wishing you could turn it up more than your BMW allows you. Towards the end of the volume scale you may start experiencing distortion, so you might want to refrain from going all the way up.

BimmerTech Alpha One speakersThe BimmerTech Alpha One speaker upgrade

The lack of tweeters and a standalone amplifier are the two greatest weaknesses of the base stereo, meaning owners of these vehicles will benefit most from a complete BMW sound system upgrade. Adding an aftermarket BMW amplifier alongside tweeters as part of a replacement speaker kit will make a drastic difference to the audio quality in your vehicle.

HiFi BMW Upgrade

Audio option: S676A / S674A*

The BMW HiFi sound system is a noticeable upgrade with tweeters (usually 2) and a 6-channel amplifier onboard. Still, the graphic equalizer option is missing and leaves the listener with the same options as the previous sound system — bass/treble, front/back, and left/right.

Higher series vehicles with the HiFi option will also include an additional midrange speaker for the center-channel dash.

With this system, you’ll get more volume thanks to the amplifier, and also a cleaner audio signal coming into it as a result of a higher quality head unit. This amplifier can be easily swapped for BimmerTech's Premium Audio System for a quick and powerful audio upgrade. In addition to the replacement amplifier's improved performance, the 64-bit DSP with 30-band graphic EQ gives far more flexibility than the limited power of the stripped back factory equalizer.

Speakers for this audio option are considerably better than for the base (stereo) option. Nonetheless, a lot of listeners are dissatisfied with the sound quality and seek aftermarket upgrades, such as BimmerTech's Alpha One speaker kit.

*Despite being branded as Harman Kardon, the S674A setup's specifications are very similar to the regular Hi-Fi option, but contain more speakers. Harman Kardon stereos in 1 or 2 Series BMWs, as well as some other models, are likely to be the lower-end S674A option, not the higher-end BMW Harman Kardon surround sound system found in more premium vehicles.

Top-Hifi - Harman Kardon Surround Sound System

Audio option: S688A / S677A

Top-HiFi is the best audio option out of all standard three and is branded as Harman Kardon in all the newer models, with option code S688A. For older BMWs, naming will vary, and the option code used is S677A. Some late E Series and early F Series models were produced with both the non-HK S677A Top-HiFi and the HK S688A Top-HiFi depending on model year. However, the difference between these setups is primarily one of branding, with all sharing a similar layout which has been described below.

With this sound system, you’ll find a surprising amount of speakers in your BMW — usually about 16. Two underseat woofers, and 7 mid-ranges along with 7 tweeters. One pair is installed in the front deck, while the remaining can be found in the rear deck and four doors.

BMW Harman Kardon tweeter

The amplifier in the Top-HiFi system has 10 channels (of which 9 are active) and is connected to the head unit by a fiber optic cable. In the head unit’s menu, you’ll find a graphic equalizer, as well as a surround sound option.

As any BMW Harman Kardon sound system review would agree, Top Hi-Fi is a significant improvement over the BMW HiFi speaker system, with more amplifier power, EQ, and additional speakers that are better quality and have higher power handling. For anybody looking to upgrade their system at a later date, the fiber optic amplifier connection means most popular aftermarket amplifiers on the market will not be compatible with the system, but it's still easy to perform a BMW speaker upgrade.

Which BMW models come with Harman Kardon?

Given the quality the Harman Kardon car audio system offers, it shouldn't come as a surprise to discover that availability is restricted to BMW's more premium models. Whereas the older Top-HiFi system (S677A) was available across the lineup, since teaming up with Harman Kardon, BMW has adjusted how it distributes stereo systems across its range of models.

Owners of recent 1 and 2 Series cars (F20/F21 and F22/F23), the current X1 (F48) or X2 (F39) or the BMW i3 will find that the premium Harman Kardon option (S688A) isn't available to them. Instead, BMW offers a more modest upgrade over the standard HiFi system, still carrying the Harman Kardon brand. This more basic system (S674A) lacks the fiber optic audio cables and more capable amplifier of the Top-HiFi system.

The quality and specifications of your car audio, including how many watts in the Harman Kardon sound system, depends on whether your vehicle is equipped with the more premium S688A system or the entry-level S674A system.

Bang & Olufsen BMW Upgrade

Audio option: S6F2A

Bang & Olufsen offer a premium audio system for certain high-end BMW models, namely the 5, 6 and 7 series, as well as the X5 and X6 (and their corresponding M equivalents). It features improved amplification, speakers, and a few other cool features.

With 16 channels and 1200W of total output power, the B&O amplifier certainly packs a punch.

Speakers are located in the same way as in the top Hi-Fi system, also divided into 2 subwoofers, 7 mid-ranges, and 7 tweeters. To add to its premium appearance, the side tweeters are illuminated, and the center channel speaker extends out from the dashboard.

BimmerTech - Premium Audio System

Audio option: N/A

There are still many reasons to upgrade your BMW amplifier or speakers, and for BMW owners that need even better audio, BimmerTech provides an amplifier and speaker upgrade — the Premium Audio System and Alpha One Speakers.


The amplifier features 64-bit digital signal processing (DSP), which allows maximum customizability with options such as EQ, crossover, delay, and others. Another benefit of the Premium Audio System BMW amplifier upgrade is an increased signal-to-noise ratio and a much higher output power, meaning more volume and clarity for the listener.

The Alpha One Speakers have the highest power handling and quality build compared to the BMW factory speakers. Mid-range and tweeter quantity will vary, and is dependant on the number of factory speakers in your BMW and additional speaker slots in your model. As a BMW-specific kit, BimmerTech is able to offer kits tailored to your exact vehicle, and with each speaker designed to closely match the factory equivalent, installing your BMW replacement speakers is easy. Kits are fully customizable, letting you opt just for a BMW underseat subwoofer upgrade, or replacing all your car's speakers. If you aren't sure how to upgrade BMW sound system, BimmerTech's plug-and-play upgrade makes it easy.

Both the Premium Audio System and the Alpha One speakers stand their ground on their own, but when you combine both of them with a custom designed DSP tuning file for the BimmerTech amplifier — you’ll be in for a ride.

BimmerTech also offers ASD (Active Sound Design) deactivation. ASD is responsible for the artificial engine sounds, which may cause audio issues or simply be annoying to listeners.

It’s important to remember though, that with all the different audio options available, specifications only tell part of the story. You won’t truly know the difference an audio upgrade can make to your car until you hear it for yourself.

Follow the link for more information on the BimmerTech BMW speaker upgrade.

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