Fan measurement chamber and claim
And since there is currently no source that offers realistic and usable data even in comparison, we have invested quite a bit of time as well as money and simply developed our own fan measurement station under the advice of a cooling unit manufacturer and then also calibrated it. Our colleague Pascal Mouchel did a great job and the result, the “Sarcophagus I” model, is quite impressive. The heavy and massive body made of thick MDF boards is screwed, glued and sound-insulated. How it all works and what we can ultimately measure and what not, you will learn in this article.
Meanwhile, most of it has materialized really nicely, also with a lot of good feedback from the community and technical assistance from some industry partners. Of course, what we can measure as of now is only up to semi-professional standards, even though all the measurement equipment has been calibrated in a complex and costly way. But that is sufficient for all areas of PC self-assembly and conversion. Of course, we are not a standardization company or the TÜV, but we try to measure everything as accurately as possible, which still remains within reasonably affordable limits.
Tests as case fans and on radiators
Currently, there is always the question of what characteristics such a 120- or 140-mm fan really has. Not every model is suitable for all radiator thicknesses, and some supposed powerhouses lose so much pressure on radiators that they can hardly be called suitable. The information on volume flow (“throughput”) and static pressure in the data sheets then also do not help when something still works well on a slim radiator and already fails completely on a 45-mm radiator.
In the picture we see the middle partition between the two chambers, which carries the fan and also the radiator. Decoupling is of course a big deal, and we thankfully had expert help in calculating the volume for the chambers. Each of the chambers is also expediently lined with dimpled foam and material-technically designed so that there are hardly any disturbing influences.
The “honeycomb” behind the fan was recommended to us by Black Noise and the cooling manufacturer. Thus, all coolers are equally well integrated, because each has a different exit angle and exactly this can be compensated with this. However, due to the honeycomb, there is no tear-off edge and the airflow is directed directly to the outlet.
Radiators and fans are decoupled and screwed tight with their own clamping device. In the picture you can see very nicely the improvised clamp with thick washers and insulation material as a base. The control is done by an Aquaero from Aqua Computer bought by us, so we can control and test the fans both by voltage (DC) or by PWM. Used both, because many fans, some do not know, can not be brought at all to the lower and upper limits of the speed band with pure voltage control and also show otherwise anomalies, about which we will write something at the appropriate place.
Volumetric flow
We measure the volumetric flow at the outlet of the second chamber where the air is blown out. This area is covered relatively accurately by comparison measurement in the measurement setup of the refrigeration partner, so that our testo 410i now delivers quite reliable results to the electronic measurement data acquisition, which coincide quite well with the reference data of the professional measurement. What is important here is not the price of the equipment, but it is the appropriate positioning and accurate calibration with series of comparative measurements.
Static Pressure
The measurement of the static pressure is done as a differential pressure measurement as usual. For this purpose, the special “cup” is clamped on so that it closes airtight. Here, too, of course, we used borrowed professional equipment for remeasurement and time-consuming calibration. For this measurement, we also use the 510i, a device we purchased ourselves from testo, and also collect the data wirelessly.
Noise emission
Measuring the noise level is a bit tricky, but works quite well in the evening hours at the measurement location. We decided on dBA or dBC because values below one sone can hardly be reliably recorded with still affordable and calibrated equipment and the software conversion of various software programs in this low range rather confuse and become inaccurate. Then rather dBA, especially since most can start something with it. The measuring distance is 50 cm to the center axis of the fan input.
We take two approaches to these measurements. For quick and plausibility tests, we use a Voltcraft SL 451, whose microphone we have placed decoupled from the body. Data acquisition is done outside the measurement chamber. The Voltcraft SL 451 was thankfully provided to us by Conrad Elektronik without complication. It is also the only component that was not purchased by ourselves. All other measuring instruments including accessories and electronics were purchased by us or provided from private stocks.
Our own purchases include a calibrated measurement microphone with XLR connector and low-noise USB interface. The measurements are made in the evening and night hours in rural areas, so that one can already be quite satisfied with a basic level of less than 26 dB(A). Since everything will be above this anyway during the measurement setup with a distance of 50 cm, this should not be a problem.
We also took the feedback from the community and evaluated the frequency band for each measurement, so you not only get the SPL values (sound pressure) in dB(A), but also a nice frequency analysis that helps to describe the sound character perfectly. Bearing or motor noise, vibrations or the tearing noise on the rotor – everything is thus mercilessly visible.
We will not go into certain details and approaches in this article, because there is definitely some foreign know-how in this setup and some things would probably be too far for the normal consumer. If you are interested and would like to build something like this, please feel free to contact us. This also applies to all who would like to contribute suggestions and hints, because we are still at the very beginning and can also still correct or expand.
What we measure and what the result then looks like, you can see on the next page using an exemplary selected fan, which is anything but our reference. That’s exactly what we are still looking for 🙂
| Test System |
|
| Chamber | Zweikammer-Messaufbau mit Schallisolierung |
| Volumetric Flow |
testo 410i (kalibriert) |
| Static Pressure(Difference) | testo 510i (kalibriert) |
| SPL | Voltcraft SL 451 (Conrad, Dauerleihstellung, kalibriert), Messmikrofon Class 2 und USB-Interface, Smaart 7 |
| Fan Controller | Aqua Computer Aquaero 6 Pro |
| Year |
März/April 2021 |
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