There was one person that gave a short review about it, but it was in the middle of a different thread. I will try to find it.

From what I recall, of course the HK system is better, but the base system was quite impressive as well.

 

That was me, and while I do not purport to be an audiophile here's my short "review" of the stock sound system.

Before putting my deposit down, I test drove a Momentum with the standard audio system and really put it through the ringer. Sat in the car for probably 20-30 minutes playing music directly from my iPhone via CarPlay. Played it at high volume and low volume, and with different equalizers. Played several genres of music: rock, acoustic guitar, symphonic, solo piano, live concert recordings, etc. The bass in the premium H-K audio is without a doubt deeper and better, and the high range is a little clearer and cleaner. But with that said, the standard audio system is very good and more than adequate for my "daily commute" purposes. I would "rate" the H-K audio to be a 9 and I would rate the standard audio to be an 8 or a 7.5 (If you want to hear a 10/10, jump into the XC90 with the B-W audio system). For an audiophile who is accustomed to listening to music on a $500 pair of Bose headphones, the standard audio system will be a little disappointing (and that person should rightly insist on the H-K system). For the rest of us, even for the rest of us who can notice the difference between a "decent" and a "good" audio system, the standard audio system is more than adequate.

Edit:
A quick overview of the 8-speaker system. There are two speakers (one large, one small) in the center of the dash. There are tweeters on the A-pillars and on the corner of the doors along the trim. In the back, there are two speakers in line with the door handle. The open-air woofer I believe is a collaboration with Alpine:
https://www.whathifi.com/news/volvo...om/news/volvo-and-alpine-find-another-way-audio-technology-to-give-you-more-mpg

 

I also do not purport myself to be an audiophile but have found the stock system to be sufficient. I would have preferred the upgraded system but I have been satisfied with the stock system. I usually listen to a mix of hip-hop, rap, R&B, rock, and EDM and usually keep the equalizer setting on "warmth".

 

I got the HK system. Even with equalizer set up to suit my tastes, I am underwhelmed by it. My other car is a 2011 Mini--stock stereo, not HK--and it blows to the XC40 HK system away. Not sure about the stock XC40 system but unless it's lousy, I wish I'd gone with it and saved $1K.

 

My wife has the upgraded HK system in her Alfa Romeo Stelvio. If you want to know how it feels to be ripped off you have to listen to that crappy system. When I heard the HK on the XC40 I was mildy amused because my ears are kind of used to the system on the Stelvio. In all fairness its much much better than the Stelvio.

I wonder if anyone has done an aftermarket upgrade on the base sound system of the XC40.

 

I sort of thought that before I borrowed a one day loaner with a stock XC40 non HK system. I was shocked at the difference in sound quality. The stock system just didn't have the depth or the base. Despite twiddling settings, I couldn't live with it knowing the difference. I was sure glad to get back into my XC40 with HK.

 

For me, I’m even slightly disappointed by the HK, mostly because it doesn’t go loud enough. So I couldn’t imagine having the stock radio.

The stock radio in the XC60 and 90 is not that great and they received so many complaints about it vs the price difference of the bowers system, they decided to add the hk as a mid range option on those models

 

XC40 Standard Sound System

I'm quite underwhelmed with the standard "high performance" audio system. Balance is way off. To feel like I am in the middle, balance is set almost all the way to the rear, and then fidelity is even worse. Seems like most of the bass is lost in this setting. Dealer says that's the way it is. I'm convinced there is something wrong, but don't know how to prove it. The spec says there are 8 speakers (I count 2 in each door), but someone else suggested there is a woofer in the dash. Does anyone know for what speakers there are and where, and what objective test can be run to determine that the system "works" properly?
White/white Inscription/T5/Premium/Vision/Butt warmers

 

I have the HK in my XC40 RD. Overall it's fine, but far from great. I was hoping an audiophile could give us the best settings to use in the EQ