Originally Posted by Gordon Scott
More volume inside the box allows the heat from the CPU out into that larger space, from where it then gets expelled out of the case. There are two gradients, CPU->Heatsink->Air_Inside and the Air_Inside->Air_Outside. The latter should be quieter if you can move the air more slowly, which should happen if there's more air volume inside the box to absorb the heat.

I agree with all I've read from others above. Low noise PSUs, CPU_Coolers and case fans all should help.

Where I differ from some is that I try to choose CPUs that are not so power hungry, e.g., the 'T' models and similar. Reduce the power dissipation within the CPU and you don't have to get so much out of the box. I'm also prepared to take a modest performance hit for lower dissipation, where others may not. That may be "just me" cool

Thank you Gordon! I always appreciate your thoughtful advice.

I think I'll go with the Fractal Define 7 XL then... it's a beast of a case, very big... but sounds like it will be quieter... and can easily be repurposed for another good build in the future (or great to use as a local NAS... can fit 18 HDD's).

I've been researching the quietest components (while keeping good performance) I could find (well besides the GPU... but I plan on keeping it "zero rpm" whenever I'm recording... no reason for it to spin up then anyways). The 9950x AMD cpu might not be the best choice... but with a Noctua D15 G2 cooler and extra Noctua fans, at idle / low-load should be perfectly fine I think.

Here's my parts list so far: https://pcpartpicker.com/list/FqdYZc