The fact is, the case design is such that rails are sold separately, the rack ears are optionally attachable, and feet are provided to orient the case tower-style under a desk. Use as a workstation chassis was a design use case, but the pedal-to-the-metal fans don’t really honor that use case.
I get where you are coming from, i just seen so many of the homelab community (especially reddit) having interesting takes on the HL15 in particular. So I have kind of figured a lot of the complaints of sound were as you say “in the living room” type scenarios. Plus when I do see pics of them posted I personally see them in racks far more than tower orientation. Its entirely possible less than 5% are rack mounted, and that I’m only stumbling on the 5% that are. I don’t know if anyone has exact statistics on what way their are being used.
I’m glad it supports both, only wish it had holes for mounting the feet for landscape orientation until I have cable run in the walls, mine must sit on a large shelf in landscape, and hoping I don’t tear of the real wood too much without feet. I am likely going to be cutting up a yoga mat to put on the shelve to protect the wood, or disassemble the HL-15 to drill/tap holes for the feet to go in landscape. Because it will move to a rack eventually, I will like use the yoga mat method.
A chassis with six 120mm fans should not need to be server-room loud to move a good volume of air. A lot of server equipment uses 40mm or 80mm fans so needs higher RPMs to move more air. Also, although noise may not be a primary consideration, those Dells and HPs and IBMs and Netapps and Supermicros do ramp the fans up and down based on load to some degree and do not operate them at a constant 100%.
Not sure on the Q30, but I remember reading the fans in the commercial 45 drives units were all Noctuas, not sure if that’s 100% accurate, also not sure if they were wired the same, or if they used variable speeds. There is a post here showing how someone did what looked like a simple mod to add a wire to control them as you mentioned, and I wonder if it would be something 45Drives could change in future builds painlessly, and maybe offer the leads with extra wires to those with machines already.
My old PC used to have 2pin fans that ran 100% but lower CFM and Noise than my new PC. New PC is all PWM fans, and if its idle its silent, if I’m encoding with steady high CPU/GPU load its loud, and if it’s in between it ramps up and down constantly which is FAR worse to me than just loud and steady. I can block out the noise of the steady 2000rpm, the ramping is very irritating even if it’s only ramping from 0rpm to 500rpm and back to 0rpm. Everyone has their own expectations. And I expect some tuning to the fans for each build, but I also don’t like the ramping, so I would have preferred a simple speed potentiometer on the power PCB. PWM seems to be what a majority of posts I read wish to have.
I will also say I have considerable hearing loss from my pass employment, so loud to me may be REALLY loud to some others.