Don’t have a Beam, but my Ones sound the same, or even a little bit better (possibly confirmation bias?). I’d suggest perhaps a power cycle of the speakers, and see if that helps?

I’ve noticed no change in audio quality with any of my stuff.  Perhaps you need to redo trueplay?  Check your settings for the speakers?

I’m not aware of any audio changes that are included in S2, but it’s possible that during the update you wound up resetting some settings. Re-running Trueplay as melvimbe suggests would be a good way to start.

Having listened further from different sources it seems that most higher quality  sources sound better , clearer possibly more processed sounding but poorer quality sources such as Twitch and Mix Cloud sound alot worse, I will re do the Trueplay tuning and see how it goes - thanks for the suggestions

i have a playbar and experienced nightmode enabled sounds now much better

https://en.community.sonos.com/home-theater-228993/s2-improved-night-mode-6842292

so far no other improvements experienced.

i would also recommend remove from power and Ryans tips.

I have a playbar with 2 play 3’s as my surround and I have the same issue with my bass, it sounds like it’s going to blow my speaker and I don’t even have it that loud. 
 

Did you have any luck with resetting Trueplay?

I completely agree, my one gen 2 has lost bass since the s2 upgrade. I contacted support who told me that the woofer had blown and have sent a replacement but this is the same!! Bass has definitely been reduced in the s2 update, speaker sounds tinny now and very poor

I was wondering if Sonos may have slightly changed the EQ curves in S2. I have an AMP powering a pair of bookshelves. I have the bass slider up quite high in my EQ. After updating to S2, I haven’t touched the EQ but it seems I’m getting a bit more room-filling bass. This is not a trueplay thing either, there is no trueplay on the AMP. However it is subtle enough that I can’t say for sure it changed, and could easily just be subjective/confirmation bias. Honestly, it sounds good though and if it is a slight bass response increase, I’ll take it. 

Sorry if I’m being obvious, but are you all aware that it seems (to me) that Sonos switches on the Loudness switch in EQ, by default? This produces a sometimes pleasing and sometimes overwhelming enhancement of the bass.