I posted a spectrograph of what I believe is a faulty Mac studio ultra. If someone (you?) who believe they have a functioning Ultra could post a spectrograph showing no peaks that would be really helpful.
I've done that already twice in this thread. vs Mac Pro
#1,232 vs Mac Studio with whine (recorded)
#415
I put up spectrum analysis graphs that show no "whine peaks" from an Ultra, and that the Ultra Studio I have (picked up on March 18) is much quieter than my 6-core 2010 Mac Pro. Also I put up relative (not absolute, not taken in an anechoic chamber) dBA measurements of the quieter Mac Studio Ultra compared to my Mac Pro, and also compared to the room background.
So there is no question that some Studio's simply do NOT have the whine problem. That is indisputable.
I do believe some Studios have the whine problem because I can hear it in recordings that have been posted and I can see it in the spectrograms I have taken from those recordings. So I believe that is also indisputable.
How
perceptible the whine is at a normal seating position in front of a Mac Studio that has the whine problem is
subjective and will depend the setup. The actual level of the whine above the background noise at a normal seating position can be measured, but since 2-3 kHz is rather directional the measured value is going to depend on the surrounding surfaces behind and around the Studio. I don't expect anyone here is going to measure or use their Studio's in an anechoic chamber where any measurements for published specifications MUST be made.
But simply for the purpose of showing the relative level of the "whine" above the background, I wish someone that had a Studio with "whine" would post a spectrum analysis taken with a mic at ear level, at a normal position seated in front of the Mac Studio, showing a "whine peak" above the background noise. Has anyone done that? If so, I don't recall. Putting a microphone 6" behind the Studio pointed at the air vents blowing across the mic is not very helpful to indicate if whine can be heard above the background of the room alone.
I've kept reading this thread simply because of my curiosity as a product design engineer of more than 40 years hoping to find clues about the cause of the whine. But at this point I doubt anything more is going to be revealed about the cause of the whine until someone pulls the Studio apart and operates it without being in the case, and can disable the fans, run it off alternate power supplies (of which we know we have two distinctively different power supplies being used in both Max and Ultra Studios), etc.