Hi guys, first time poster here, have been lurking for a while, ever since I placed my order on kickstarter.
Thank you Daniel for this amazing case.
I am new to the SFF crowd, coming from the silent PC world (silentpcreview.com), having spent quite some time and energy on minimizing the noise coming from my PC. My whole setup resided in a Fractal Design Define R5 before. All I did, was to get another mobo and PSU and move everything over into the Dan Case. To be honest, I was a bit sceptical, if this would work out for me, as the R5 setup is just quiet. Never heard a thing of it. It did work out in the end, but it took a few measures.
A few words on airflow:
The main idea about airflow in the silent PC world is to create a path for the airflow, which is as unrestricted as possible. No obstacles (HDD cases right behind the intake fans), no corners, which the air has to move around (intake fan blowing into the case horizontally, exhaust fans sitting in the top, blowing out vertically). Air is so light, we do not feel it normally. Nevertheless, every molecole in the air is subject to inertia and thus does not want to change the direction of it's movement. This is not to be underestimated.
So the ideal build from this point of view creates an airflow in one straight line. For example: 1 intake fan in the front panel (with no HDD cage behind), 1 cooling fan sitting on the heat sink, 1 exhaust fan at the back. All three of them in one line. This will create the maximum effect, with the minimum of effort and noise. Quite simple, actually.
If you want to maximize this effect, you will create a duct (tunnel), to avoid air moving astray.
The concept of positive and negative pressure setups:
A regular PC case offers multiple spots to mount a fan. Some of them will act as intake fans, others will operate as exhaust fans. There will also be cooling fans inside the case, sitting on your heatsink and GPU.
If you only mount intake fans and no exhaust fans it is called positive pressure setup. Pressure will build up inside the case and the (hot) air will be forced out of the case. Upside of this setup is, that you will have a nearly dustfree environment inside the case, if you combine this with dustfilters at the intakes. Downside is, at equal temperature levels it will be a bit louder than a negative pressure setup.
If you only mount one or more exhaust fans, without any intake fans, it is called negative pressure setup. There will be a very slight vacuum inside the case, so air will be sucked into the case at every possible gap. Downside of this setup is increased dust buildup inside the case. Upside is, it is mostly a quieter setup.
Most people will build a mix of intake and exhaust fans to create a slightly positive or negative pressure setup, which will work out as the best balance between maximum cooling at minimal noise. If you combine this with a good airflow in mind, you will end up with a pretty silent setup.
Now, to get to the actual point of this post:
What makes the Dan Case so special to me, is that each fan operates at the same time as intake fan, cooling fan and exhaust fan. The suction side of the fan is it's intake function, the pressure side is it's cooling and exhaust function. To make this work, you have to strictly separate the suction side from the pressure side. Otherwise, a certain amount of hot air will be recycled through the heatsink. Again, quite simple.
Here is, what I did: Create a small duct for the CPU fan, which separates the suction side from the pressure side. A cardboard strip (cereal box in my case) of 20mm width, is enough for the NH-L9i.
