I’d second this - the lowest possible volume is way louder than with any other headphone.

This appears to have been fixed in the latest update for the headphones. Thx Sonos team! 

Sadly, that is not the case for me as of the latest software update. The Ace have a markedly better sound profile that my APM; however the precision of the latter’s volume control, especially at the lowest volumes, is peerless. It is quite granular and decreases to the point of barely hearing sound. This allows me to read, write, reflect, or sleep without intrusion.

The lowest volume level on these is far too intrusive for the quiet enjoyment of one's music during said activities, which is a real shame and perhaps not a priority for Sonos. I wear ANC monitors to shut out not create distractions, so it pains me to say that I may end up returning these despite my deep appreciation of their sound profile.

This feedback relates specifically to my use of the Ace headphones with my iPhone and iPad. I would note that other OEMs (eg, Bose QC Ultra earphones and earbuds) have the same issue, but I expect better from a more expensive product. I received my Ace headphones today and updated them to the latest software prior to researching the issue because of how unbelievably loud they are at the lowest volume at which they will produce sound (ie, 2 in the Sonos app).

Yeah, I spoke too soon. When I tested with a few other devices, the lowest volume level is still too loud for me as well.