As far as the IronWolf goes, the 2TB and 3TB models have different sound ratings. Here is the spec sheet which covers both capacities as well as others. 2TB IronWolf (ST2000VN004): IDLE - Typical 1.9 bels, Max 2.0 bels SEEK - Typical 2.1 bels, Max 2.2 bels 3TB IronWolf (ST3000VN007): IDLE - Typical 2.3 bels, Max 2.4 bels SEEK - Typical 2.5 bels, Max 2.6 bels
The original post does talk about ST2000LM007, which was a 2.5" laptop drive, keep in mind the IronWolfs are 3.5" drives. Here are the sound acoustics from a 2TB BarraCuda just to give an idea of how the IronWolf does in relation to a standard desktop-grade drive (spec sheet for the BarraCuda here): 2TB, 3.5" BarraCuda (ST2000DM006): IDLE - Typical 2.5 bels, Max 2.6 bels SEEK - Typical 2.7 bels, Max 2.8 bels
If you wanted another 2.5" drive to compare to, here's the 2.5" version of the 2TB BarraCuda (spec sheet here): 2TB, 2.5" BarraCuda (ST2000LM015): IDLE - Typical 2.0 bels, Max 2.2 bels SEEK - Typical 2.2 bels, Max 2.4 bels
Given that information, the 2TB IronWolf comes out the winner on quietest drive as far as these offerings go. Just keep in mind that the 2TB, 3.5" BarraCuda is 7200 RPM, while the rest of the drives on this list in these capacities will be 5400/5900 RPM.
Regardless of which route you decide to go in the end, thanks for considering Seagate!