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Category: BMW Sound System

All you need to know about BMW Harman Kardon sound system – Is it worth upgrading?

Bianka Rommel

Oct 12, 2022

All you need to know about BMW Harman Kardon sound system – Is it worth upgrading?

Honestly, we could go on and on about BMW sound system specs – which we do in fact here for those interested – but a lot of you only want to know one thing: which system has the best sound. The BMW Harman Kardon sound system is a mainstay, and sometimes the best you’ll come across on the dealership floor. But does it live up to the hype? Or is there better sound on offer if you upgrade? 

We take a deep dive into BMW’s Harman Kardon system – or should that be systems, because no fewer than three completely different audio setups have carried that name so far. When we know what we’re dealing with, we check in with a few avid music fans, who, in their own words, compare their factory Harman Kardon systems to the Alpha One upgrade. 

So for all the audio enthusiasts out there looking for a new BMW stereo set, or wondering whether their BMW Harman Kardon sound system would benefit from upgrading, it’s worth taking a look at what they have to say!

What is Harman Kardon in BMW?

If you’ve never heard a single thing about Harman Kardon, you must have been living under a rock for a good three decades. To put it briefly, Harman Kardon is a renowned American car audio supplier that’s been in consistent partnership with BMW for 11 years.

The unweakened bond between those two doesn’t however mean that Harman Kardon stereos are as good as it gets. You can always strive for better ;)  

To start things off, let’s clarify that there are two poles-apart BMW sound systems branded as Harman Kardon – the BMW Harman Kardon Hi-Fi system (S674A) and the BMW Harman Kardon surround sound system (S688A). To complicate things even more the S688A Harman Kardon system is different (we wage to say better) in pre-iDrive 7 BMW’s like the F15 X5 or F10 5-Series compared to the 688 HK system installed in iDrive 7 equipped BMW’s like the G05 X5 or G20 3-series. Opinions differ on this, most of our customers that upgraded their X5 for the newer model reported being disappointed with the latest iteration of 688 HK.  If you’re in the market for a new Bimmer with a mighty HK in it, it’s pretty important you know which one’s which to avoid staggering disappointment.

Why’s that exactly? Some of you may be under the impression that what you call a Harman Kardon must carry the aura of the household audio system, with its astonishingly high volume levels. Yet, as a matter of fact, the BMW Harman Kardon Hi-Fi system (S674A) is only a modest relative of the BMW Harman Kardon surround sound system (S688A), and was dedicated for smaller chassis cars. That, of course, was a great misfortune for many i3 or 2-Series owners who expected to be swept off their feet by the heaps of power when seeing HK logos on speaker grilles, but ended up with an audio set which barely resembled the expected quality.

If you don't know which BMW sound system you have, decode your VIN and we’ll send you the full vehicle specification list.  Relevant option codes to look out for are S674A, S676A, S677A, S688A, S6F1A, S6F2A and S752A.

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BMW Harman Kardon speakers

BMW HK Hi-Fi system (S674A)

The BMW HK Hi-Fi system (S674A) consists of 12 speakers and an 8-channel BMW amplifier fitted in the trunk (with only 7 channels used to power the speakers)... Meaning, the overall audio quality is decent, but it’s far from audiophile standards. This system is very similar to the regular 676 Hifi Audio system as it even uses 2 ohm woofers like the Hifi system.

BMW HK Hi-Fi system (S674A)

BMW Harman Kardon surround sound system (S688A)

The BMW Harman Kardon surround sound system (S688A) known from pre-iDrive 7 BMW’s on the other hand is probably the one you have in mind when thinking of a premium sound system. This abundant option, appearing in larger vehicles such as the X5, 3 or 5 Series, usually comes with 16 speakers – including 2 (8 Ohm) woofers, and 7 mid-ranges along with 7 tweeters placed all over the vehicle. And sure, they’re more than decent – certainly much better than most of the stock options – yet still not quite there as an enthusiast-level standard. 

BMW Harman Kardon surround sound system (S688A)

For people who have them and are into sound system customization, it’s also worth keeping in mind that the BMW Harman Kardon subwoofers come with an 8-ohm impedance, which is higher than you'll find in other BMWs. Hence, when replacing the woofers for something a bit beefier, staying within a similar impedance will be much more beneficial to the audio effect.

BMW Harman Kardon amplifier (pre-iDrive 7)

Now, Harman Kardon’s (S688A) heart – the amplifier. Having 10 channels with 600W of max power to shake up your whole neighborhood, it’s undoubtedly the heaviest hitting out of all the standard factory BMW amps. Compared to others, it uses fiber optic wiring to keep the digital signal as clear as possible and the music sounding just as it was recorded. 

Thanks to the BMW Harman Kardon equalizer settings, you can also customize the music to your liking right from the head unit level.

Compare that to the little brother amplifier in the S674A system – 7 channels, lower output (BMW quotes 360W MAX, but we doubt that to be true) and fewer customizability options. In reality, it doesn’t sound more powerful than  BMW's run-of-the-mill 205W Hifi amplifier, only improved by the slightly better quality of the Harman Kardon branded speakers. You'd definitely hear an improvement stepping that amp up to a more premium option.

Want to know more about the amplifiers’ role in your BMW audio? Check out this blog post.

BMW Harman Kardon amplifier with iDrive 7 and up

When iDrive 7 was introduced the audio system architecture was completely redesigned for all audio system options from base stereo, through Hifi, Harman Kardon and all the way up to Bowers & Wilkins audio systems. These systems are no longer completely dissimilar to each other. In fact, all of them share a common module called a Receiver Audio Module or RAM for short. Obviously the RAM module is different in a base stereo car compared to a Hifi and Harman Kardon system but their build and sound quality is similar.

The RAM has up to 7 speaker level audio outputs so it is not enough to power all 9 speaker channels of a Harman Kardon system. BMW solved that by adding a second audio amplifier into the mix, called a Booster. What a neat name. The booster has two additional speaker level power outputs and is used to drive the woofers, while the RAM takes care of driving all 7 midrange + tweeter channels.

The MAX power output of iDrive 7 Harman Kardon systems ranges from 464W for most modern BMW’s like the 3, 5, 8 and X series chassis. Oddly enough, BMW lists the 4’s Harman Kardon Audio system as a 600W system and the iX as having 655W with 18 speakers compared to the usual 16. If we pretend we didn’t see the iX’s and 4’s power numbers that would mean late model BMW’s HK systems lost 136 watts of power compared to the older 688 HK system, and you can hear it.

While max output power does not determine what an audio system sounds like, it's an important part.Harman Kardon chip shortage 2021/2022
It’s the HK amplifier – or more precisely, the computing chip built into it – that made the BMW Harman Kardon system so difficult to come by in 2021. A global microchip shortage severely limited availability of the Harman Kardon and other premium audio systems, leaving many new BMW owners to rely on aftermarket retrofits instead.

Harman Kardon vs BMW HiFi System

While the HK amp and its customizability options make a difference, another obvious difference between the S688A Harman Kardon system and the standard S676A HiFi option present in most vehicles is the speaker count.

The exact numbers are going to differ depending on your model, but when kitted out with Harman Kardon, BMW 3 Series vehicles gain extra tweeters in the rear doors and a pair of midranges and tweeters in the rear shelf. The BMW X3 Harman Kardon system and BMW X5 Harman Kardon system both also add extra rear speakers, but put them in the D-pillar instead of the shelf.

That means more speakers and a more immersive sound with the factory stereo, as well as an easier upgrade route when it comes time to swap the stock speakers out.

Compare Harman Kardon and BMW HiFi sound systems

Which BMW models come with Harman Kardon?

Since BMW started partnering with Harman Kardon 11 years ago, during the production run of the E9x 3 Series, all 2010 E9x and many later models started featuring the S688A Harman Kardon sound system with the powerful amplifier.

But, due to space constraints, the little guys (such as MINIs, 1 Series, 2 Series and i3s) unfortunately had to go without and include the less robust S674A option instead.

BMW Harman Kardon option price

So how much are you going to have to shell out to get Harman Kardon in your BMW? As always, it depends.

In the US, the Harman Kardon stereo is available as part of the premium package, which as of 2022 will add $2,250 to the price of a new 5 Series off the dealership floor. That’s bundled with other features like power tailgate and heated seats, so if you’re only interested in the audio side of things, you’re paying extra.

UK drivers can pick up the Technology package for their 5 Series for £2,495, which also includes the HK system alongside other features. Alternatively, it’s a standalone £820 extra.

Of course, prices are likely to vary depending on your market and the model you’re interested in.

How do I know if my BMW has Harman Kardon?

HK certainly doesn’t hide its presence around the vehicle, so you’ll most likely notice it at one point or another, whether that would be by Harman Kardon branding scattered on every single speaker, or the sizable speaker count itself. 

Probably the best way to spot it though is through the equalizer settings and surround sound option in the iDrive menu – after all, HK is not just hardware, but an audio system with a multi-band graphic equalizer and audio adjustment possibilities.

If your iDrive audio settings look more stripped back than that, then there’s a good chance you don’t have Harman Kardon in your BMW and might benefit from an upgrade.

What other BMW speakers brands are there?

That said, Harman Kardon isn’t the only name you’ll find on BMW’s higher-end stereo options – though it’s by far the most popular.

Higher up the scale, you’ll find BMW speakers from Bang & Olufsen, or more recently Bowers & Wilkins. Both offer better sound than you’d get from the Harman Kardon car speakers – which are more like everyday premium than full-on luxury – but are also much more difficult to lay your hands on.

BimmerTech Alpha One vs Harman Kardon BMW sound system

Ok, so you’ve checked and are 100% sure you’re part of the HK team. Lucky you :)

But, can you do better than that?

Well, there’s always room for improvement!

With BimmerTech’s high-end Alpha One speaker upgrades, you’ll definitely get that extra bit of crispness, punch and clarity from your BMW Harman Kardon surround sound (S688A) system to make your audio unrivaled. We prepared our Alpha One speaker kits to match your needs, so whether you decide to replace your full speaker set or only the subs, that won’t lessen the knock out effect of a premium upgrade.

And if you have a BMW with HK (S647A), upgrading the Alpha One amplifier alongside the speakers will pump in even more power, optimized stereo imaging, smoother frequency response and more customization possibilities than before. 

Learn more about personalizing your BMW sound system with DSP tuning.

Don’t take us on our word? Check out BMW Harman Kardon sound system reviews and see what others make of it.

Bryan from Kies Motorsports, 2019 BMW 3 Series – Harman Kardon (S688A)

Let’s start off with our not so newbie reviewer – Bryan from Kies Motorsports. 

Bryan tested out our speakers on his buddy’s 2019 BMW G20 M340i with iDrive 7.0 and BMW Harman Kardon surround sound system (S688A). As he put it well, a YouTube video is never going to give out the authentic differences between the two systems – especially the all-encompassing deep bass, which you’re only bound to feel through your bones. So to fill the void of what video websites can’t deliver, he described the subtle contrasts in his own illustrative words: 

Stefan the BMW DIY Guy, 2016 BMW M2 –  Harman Kardon (S674A)

In this audio upgrade, we went full on ;) 

Since Stefan’s F87 M2 was equipped with Harman Kardon (S674A) we were able to replace both his complete set of speakers as well as the amp – and most importantly what comes with it – personalize the sound design according to his musical taste, his style of listening and car chassis. The result? Hear for yourself:

CJ from BimmerTech, F15 BMW X5 – Harman Kardon (S688A)

CJ’s SUV was equipped with BMW Harman Kardon surround sound system (S688A), so it already had a proper audio kick to it. However, what CJ felt he missed out on was the possibility to crank the music all the way up and not worry about any distortions coming out from the speakers. Our BMW F15 speaker replacements worked perfectly for that – the tracks got cleaner and more resonant at low frequencies, and didn’t lose their crispness in the highs. Our friend couldn’t be happier!

How to replace BMW Harman Kardon speakers – installation

customer reviewSo, let’s say you’re convinced – you badly want to upgrade your Harman Kardon BMW stereo! 

… And now what? How are you going to handle this few hour install?

Well, you’ve got two options. You can either install it by yourself or with the help of an authorized expert. 

If you feel it’ll be a tough nut to crack for a rookie DIY-er like yourself, you couldn’t be more wrong ;) We’ve designed our BMW speaker upgrades to match every bolt and screw of the stock kit, so the installation is as straightforward as disassembling and removing the old set and popping the new one in. No cable trimming or installing additional parts will be necessary – it’s just an easy plug & play procedure that will take 4 hours of your spare time. Should you ever feel like going back to your factory setup, you can freely do so, since the upgrade is fully reversible. 

Is ‘straightforward’ too vague for you? Let’s put it this way then – if you’re doing ok with IKEA projects, you’ll be totally fine with this one ;) Here’s an exemplary install of our BMW speaker and amplifier upgrades in M2 with Harman Kardon (S647A).

For folks who were not born to tinker or simply don’t have enough time to spare, we’ve also got a broad network of authorized installers, who can handle this job in no time. Check the nearest one to you.

Want to hear more about the BMW Harman Kardon speakers and amplifier? Let us know down below in the comment section. We’re open for your ideas!


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