I put one in my garage and while there is a whooshing sound of air moving, it is nothing like the high pitched whine from S9's. the noise is easily bearable and much better than the dual-fan miners. Thank god! Note I have it venting into an AC duct so that helps some but other than that it's open.
Yeah, these Z9 are still actually bearable for home use especially if you compare them to the S9s. Even with a DIY cooler case my S9 would still drive me and my entire family crazy with the noise. It turned out to be a good thing though as I was able to sell my S9 for $2500 back then when they are now selling at around $750.