I did quite a bit of in person testing and I wanted to share my thoughts on the S class, the 7 series, the A8L, the Volvo S60 - all top tier systems. I listened to them back to back, in depth, while the vehicle was parked. I learned quite a fair bit. If you're looking for a biased opinion for the car you like, you're not going to get it here. I was actually very taken aback by these systems but not for the reasons you might think. I have to go off of memory for the LS500's Mark Levinson system so I'm not going to include that here because human memory can be flawed.

First off, I was shocked at how different the sound profiles are on these cars. I've listened to some of these cars over the years, some previous gen models, but man, listening them back to back really gave me an appreciation of these systems. I don't think there's a specific winner, but I ABSOLUTELY think I know why people tend to be so polarized over the "vehicle" / "sound system" that they like.

In no particular order: (again, these are all the most expensive systems - and I don't want to type out all the details of their names)

1) The Audi A8L ->I no longer would use the term "reference audio" for this system after listening to all of them. One word to sum up this system? "Wide" -> extremely wide out of all of them. It's clear Audi spent serious $ working on their algorithm for this one. The sound stage is wide and, I would dare say "energetic". Going from the car I love to the other ones, this was my main takeaway. The other is - B&O focuses on being equally strong on the bass side and equally strong on the treble side. The range is extremely dynamic.

2) The S class 4D -> Definitely the most appealing to the vast majority of people. The sound is present, fairly warm too, very punchy, very gutsy. It's an extremely solid system. I'd say it has some reference audio qualities, but it's clear to me Merc designers designed this system to appeal to the mass market's ears. It's not nearly as artificial sounding as the A8L, but it's not as cold/referency as the LS500's (off of memory). The S class shines extremely well for the "mids". Extremely. I'd say the A8L - S class - 7 series (ranging left to right). Now let me get to the 7.

3) I was genuinely surprised by the sound system of the 7. It sounded very hollow/distant/far to me. There were 4 settings I could choose from, and I wasn't that enamored with it. I don't know if 7 refers to their highest end sound system as 'reference' but it felt a bit cold / clinic-ly to me? The interior is gorgeous and I had to stop myself from focusing on that, but I was left very surprised by the 7 series. It had some Meridian vibes to it and I'm fine with the one in my Range Rover, but it just felt so....strange? It's almost like the music lacked energy? Like it was playing in another room?

4) This is why I went to try the top end Bowers system on the Volvo S60. I wanted to know if it's a BMW thing or a Bowers thing. It's more a Bowers thing I've learned. On the S60 it's more appealing/warm, but yeah in general B&W tends to be less dynamic and more referency if that makes sense? Less energetic. Less present? It's such a weird sound stage to me for both of the Bowers systems

I want to be extremely respectful to the 7 series owners on here. I have little doubt - in fact, I am sure that a 7 series owner would jump into an S class and go "wow, that's different", and I'm also sure they'd jump into a Audi A8 and go "oh ok, that sounds weird".

So it's all a matter of perspective. As far as which system I liked best? Honestly - maybe the S class. My ears have gotten used to the A8L and I REALLY REALLY ADORE this system and how wide the stereo stage is. It's one thing I really like about the A8L - a moving concert hall. However, I think the S class is better tuned for the vast majority of ears, and perhaps even more genres of music than the A8L.

I will state that I"ve taken the 7 series off of my list though. I love the interior, but the sound system wasn't for me (I didn't say it's bad! - I just said it's not for me). The S class remains on my list. I guess I have Burmester/B&O ears and not B&W! To each their own I guess.

It was extremely fun though to be able to test all of these too. I also tested the bespoke Audio system on the Rolls Royce Spectre not too long ago. It's somewhere in between all of these systems. Nothing about it made me go "yeah, it's much better than on German flagships". It's not.

I've been thinking about how to writeup my experience, I guess it'd be:

1) The A8 feels like music is all around and beside you
2) The S class feels like music is in front of you grabbing you by the lapel
3) The 7 series feels like music is in the room in front of you, but probably the most "accurate".

...I'm still lacking words right now. I can't walk away from my experience and go "X system is the winner". It's like asking me what's better. Spaghetti or Coffee.

The first word leaving this testing experience out of my mouth was "wow". I'm shocked.

 

And with that, I went to Gemini to get them to summarize what professional audio reviewers think. Copy & pasted. I think I sorta nailed it on the same head

Choose the BMW / Bowers & Wilkins if you prioritize pure, non-fatiguing vocal realism, pristine acoustic imaging, and high-frequency sweetness.

Choose the Mercedes / Burmester if you want the ultimate implementation of Dolby Atmos, technical linearity, and a near-zero distortion floor.

Choose the Audi / Bang & Olufsen if you love a vast, wide soundstage, hyper-articulated mid-bass punch, and a striking visual presentation.