Luxa2 LM100 Mini: "Exquisite & Desirable" m-ITX HTPC Case

TESTING

System Configuration:

• Intel Core 2 Duo E7200 processor - 2.53GHz, 1066FSB, 3MB L2 cache, 45nm, 65W
• Arctic Cooling Alpine 7 Pro and Coolermaster Geminii S CPU coolers
• Corsair XMS2 memory - 1GB, DDR2-800
• OCZ Vertex 30GB SSD
• Microsoft Windows Vista SP1 operating system - Home Premium, 32-bit
• Luxa2 LM100 Mini case with power supply

Measurement and Analysis Tools

• CPU-Z to monitor CPU frequency and voltage.
• Prime95 processor stress software.
• FurMark stability test to stress the integrated GPU.
• SpeedFan to monitor temperature and fan speeds.
• Seasonic Power Angel for measuring AC power at the wall to ensure that the heat output remains consistent.
• Custom-built, four-channel variable DC power supply, used to regulate the fan speed during the test.
• Various other tools for testing fans, as documented in our standard fan testing methodology.

Primary Audio Test Tools

• PC-based spectrum analyzer: SpectraPlus with ACO Pacific mic and M-Audio digital audio interfaces.
• Anechoic chamber with ambient level of 11 dBA or lower

System temperatures and noise levels were recorded with SpeedFan at load using Prime95 to stress the CPU and FurMark with the Xtreme Burn option (if possible) to stress the GPU.

Baseline Noise

Noise measurements were made of the case with the two supplied fans at various fan speeds. The air cavity resonances inside a case amplify fan noise, as do any vibrations transferred from the fans into the case, so these measurements can be regarded as the baseline SPL levels for the LM100 Mini with the stock fans.

The case sample we received was equipped with two 50 mm fans — one of them sounded fairly smooth and broadband, while the other had some tonality, a bit of whine, and developed a 'wobble' at higher fan speeds. It may have been damaged during transport, but the other fan wasn't afflicted, so quality control is likely the issue. Luckily, the bad fan didn't affect our noise measurements — both fans measured approximately the same in our anechoic chamber.

The overall noise level was very low with one fan at 9V or lower, or with both fans at 7V or lower. However, the amount of airflow generated with these configurations is almost negligible. To make these fans worthwhile, they must both be running at 9V or higher. At 9V, the two fans produce about 21 dBA@1m inside the case with nothing else running. This is more than adequately quiet for a home theater type setup with the case several feet away from the user. On a desktop, it will sound much louder — it measured 30 dBA at 0.6m, the ISO 7779 PC noise test standard reference SPL measurement distance for a seated user.

Spectral Analysis: both case fans at 12V (blue) vs. both fans at 9V (red).

Strangely, we found that the measured SPL at 0.6m was the same whether the two fans were running at 9V or 12V. Subjectively, the noise level sounded higher at 12V, but it seems that at 9V, the two fans generated a sharp frequency spike at approximately 380 Hz. This spike is weighted heavily enough to give 9V operation the same 30 dBA measurement as 12V. This is one example where objective data is less useful than subjective real-life human percepion.

We also tested the SPL with the power supply turned on (with no load) — it hardly added any noise the system, even after being left on for 10 minutes. It was only audible up close, producing a soft buzzing noise.