Hi @JasonSC
Welcome to the Sonos Community, and apologies for the delay in replying!
There is no reference to too low a volume on Ace in our internal documentation, and an engineer I asked knew nothing about it - I can only presume that too few users called in to report it (I did find the community threads relating to it, but that’s all) for anything to be done about it. I can only presume that very few people ever wear the headphones and set the volume to the lowest level.
I would therefore not expect Ace Ultra to be any different, but as I don’t have a set, I really can’t say one way or another.
My replying here will get this thread back on the list of those recently active - perhaps someone possessing both Ace and Ace Ultra will be able to give you a more definitive answer.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein