BMW Harman Kardon Sound System Overview & Upgrade

Forget about horsepower or torque, fuel efficiency or heated seats. For many people, the single most important feature a car can have is a top quality stereo system.

And the auto manufacturers know that. That's why so many have teamed up with some of the world's top audio brands, to develop speakers and amplifiers a step above whatever your neighbor's car is packing. Good to leave sound to the experts, don't you think?

In BMW's case, that expert is Harman Kardon. With one of the biggest names in home audio and a world-renowned automaker, the Harman Kardon / BMW partnership has been going strong for over a decade. And as you'd expect when two brands of such pedigree come together, there have been some pretty impressive results.

But what can you expect from your BMW Harman Kardon speakers and amplifier? And are there even better speakers for BMW available (spoiler alert: there are ;))

What is BMW Harman Kardon?

The first thing to keep in mind is that there are two distinct BMW sound systems carrying the Harman Kardon name. So if you're looking at buying a car and feeling swayed by a BMW Harman Kardon upgrade, it's worth making sure you know which one is which.

The first (the Hi-Fi system Harman Kardon with option code S674A) is a more modest offering. You'll generally find it in BMW's lower-end models, like the 2 Series, i3 or in MINIs. It's got the Harman Kardon name on it, but it might not live up to the exacting demands of many audiophiles.

The second (the BMW Harman Kardon surround sound system with option code S688A) is the one most people are probably thinking about. A clear step up from its sibling, it's placed at the top of the standard stereo options BMW offers, appearing in larger vehicles like the 3 and 5 Series or X5.

Importantly, that top-tier S688A Harman Kardon option is not currently going to show up in the smaller BMWs. As it's what most people have in mind when they think about BMW Harman Kardon speakers, make sure you don't end up disappointed when your new i3 isn't pumping out sound like your buddy's X6.

So what is it that makes the S688A Harman Kardon stereo system so popular? It's all in the numbers: more speakers, more amp channels and more power. And a few other numbers, too… the 1's and 0's that go into its crisp digital signal.

BMW Harman Kardon amplifier

Compared to the 8-channel amp found in the entry-level BMW stereo systems (and the HK S674A system, for that matter), the BMW Harman Kardon amplifier has 10 channels, with more power to boot. Unlike other factory options, it also uses fiber optic wiring to keep its digital signal as clear as possible, to keep your music sounding the way it was recorded.

BMW Harman Kardon speakers

When it comes to the speakers, you'll find them… just about everywhere. Whereas the lower stereo systems might see a spot in your car a speaker would fit and decide “nah, not this time”, the S688A system isn't so picky. Doors, rear shelves, pillars — if you could squeeze a speaker in there, Harman Kardon will.

Exactly how many speakers that comes to depends on your model, but 16 is a good ballpark figure. It wouldn't live up to its surround sound billing otherwise, after all. 

Not that speaker count is everything; all the speakers in the world won't help you if those speakers aren't up to par. Compared to BMW's other factory options, the Harman Kardon speakers are a step up, but audiophiles would still benefit from looking at ways to upgrade to enthusiast-level hardware.

And if you are the kind of person who likes to tinker with their sound system, it might also be worth remembering the BMW Harman Kardon subwoofers have an 8-ohm impedance — higher than you'll find in other BMWs. When it comes time to switch out your woofers for something a little beefier, keeping the impedance in that area is going to give better results.

Which BMW models come with Harman Kardon

The Harman Kardon / BMW partnership started in 2010, during the production run of the E9x 3 Series. That means late-model E9x and subsequent generations of BMW are all in the running to feature the S688A Harman Kardon system.

…but not all do.

Whether it's because the hefty BMW Harman Kardon amplifier and plethora of surround sound speakers wouldn't fit in BMW's more nimble cars, or because the Bavarians want to keep something special for only its flagship models, the Harman Kardon surround sound system isn't one for the little guys. You'll only find it available for 3 Series and up and SUVs like the BMW X3 and BMW X5 — M2 drivers, you'll have to enjoy the sound of your engine instead 😉

How do I know if my BMW has Harman Kardon?

When you're buying a new car, you can always ask for the BMW Harman Kardon upgrade. But what if you've already got a car, and just don't know what system you've got? You could always try to hunt down a little Harman Kardon branding scattered around your car, or start counting speakers, but isn't there a better way?

As luck would have it, there is.

The Harman Kardon audio system in BMWs isn't just hardware. It's backed up by DSP software, too.

Head into your iDrive menu and you'll find the BMW Harman Kardon equalizer settings with a multi-band graphic equalizer that gives more control than the simple bass/mids/treble sliders you get with the lower-tier systems.

And don't forget it's the Harman Kardon surround sound system, and they didn't call it that for nothing. You'll also find a surround sound option on your menu, that you can toggle on and off.

Equalizer and audio settings on your iDrive looking a little sparse compared to that? Well, that's a good sign you don't have the Harman Kardon system, and might want to take a look at an upgrade.

BMW Harman Kardon sound system upgrade – Is it worth it?

So is it worth getting that upgrade?

If you're into your music, then sure, if only for the sake of the amp. The BMW Harman Kardon stereo is a clear step above the more basic BMW sound systems, thanks to its crisp digital sound, powerful amplifier and improved customizability. It's much closer to what you'd expect from a home stereo system — with the added benefit of wheels, so you can take it anywhere 😉

That isn't to say it's the best money can buy, though. But “money” really is the key word there; you can get even more capable sound systems from the factory, but when it comes to BMW Harman Kardon vs Bang & Olufsen, cost really is going to have to be at the front of your mind. Business as usual for B&O, I guess.

BMW Harman Kardon speaker replacement

That good news is that it's always possible to step up the Harman Kardon system with the right BMW aftermarket speakers upgrade. Particularly when you remember the 10-channel HK amp and flexible DSP is a capable workhorse.

Thanks to BMW audio experts like BimmerTech, it's easy to upgrade your BMW speaker system, whether you've got Harman Kardon or another stereo system. The Alpha One range of speakers is made specifically for BMWs, so will plug straight into your car in place of the stock BMW speakers without any modification required.

It's the best of both worlds — the powerful OEM BMW Harman Kardon amplifier, paired with expertly designed BMW aftermarket speakers for even greater clarity and performance. What could be better than that?

Find out about BimmerTech's Alpha One speaker upgrade for BMWs.