Just got my Rigol DHO914 and I like it but the fan noise is really getting on my nerves, not specifically how loud it is but the tone of it.
I'm playing with the idea of adding a replacement fan on the rear, a NoctuaNF-B9 Redux-1600, this fan runs slowere and much much quieter but as it larger it moves more air and even mounted on the rear of the case with a 3D printed bracket, the short test I did ran 2 degrees cooler than with the stock fan and I couldn't even hear it.
Now this is a first off proof of concept and needs some more fiddling to get the bracket so it doesn't hit the desk when leaning back and to be able to mount it on the VESA mount but it proves, to me, that the larger slower quieter fan is the way to go.
Does anyone know if there's a 3D model of the rear cover out there?