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PostPosted: Mon Aug 12, 2002 2:32 pm 
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Judging by the <!-- BBCode Start --><A HREF="http://www.silentpcreview.com/modules.php?op=modload&name=News&file=article&sid=106&mode=thread&order=0&thold=0" TARGET="_blank">fan comparison chart</A><!-- BBCode End --> just published on this website, the 80mm Papst 8412N/2GL fan <!-- BBCode Start --><I>should</I><!-- BBCode End --> be considerably quieter than the popular 80mm Panaflo L1A. Here is part of the data, with both fans running at 7V ("50% RPM" in the chart): <BR> <BR>Papst: -3.1dBA (yes, negative 3.1) and 9.7CFM <BR>Panaflo: 5.9dBa noise and 12.0CFM <BR> <BR>In other words, Papst is supposed to deliver 80% of the airflow at an incredible 9dB lower noise. This makes me wonder: have any real-life tests compared the Papst and Panaflos? I'd be really surprised if it's really <!-- BBCode Start --><I>that</I><!-- BBCode End --> much better. <BR>--Leo
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PostPosted: Mon Aug 12, 2002 2:32 pm 
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I think you may have found an error in the table, Leo. I'll pass this on to the author. <br> <br>In the full table (XLS or PDF), you'll find that data reads 3.9 dBA and 13.2 CFM, which is still impossibly low, given the residual noise that any fan would make regardless of rpm. <br> <br>I don't have a 8412N/2GL to compare, but I do have one PApst 8412NGL sample (only one, however...) that is rated at 12 dBA, compared to the 21 dBA of the Panaflo. IMO, without any measurements, I don't believe there is a 9 dB difference between them. What I hear is that the Panaflo bearing has more broadband (sheeeeeeee) noise than the Papst, and also a higher pitched whine. It spins faster. But the Papst vibrates more and has some ticking/clicking noise. Airflow? pretty similar, I would say, but at 5V, the papst is not usable -- no airflow at all, and iffy on startup.
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PostPosted: Mon Aug 12, 2002 2:32 pm 
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Thanks for clarifying this, Mike. <br> <br>Different manufacturers' dB ratings seem to be inconsistent--I remember using an Adda "16dBA" 60mm fan, which was much louder than the "22dBA" Panaflo. Another reason why we need independent reviewers so much <IMG SRC="modules/phpBB_14/images/smiles/icon_biggrin.gif">
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>>In the full table (XLS or PDF), you'll find that data reads 3.9 dBA and 13.2 CFM, which is still impossibly low, given the residual noise that any fan would make regardless of rpm. <br> <br>Take a closer look at the XLS file. Those numbers are calculated. The one fan dBA and CFM are the manufacturers' figures. The rest is just dodgy formula. <br> <br>
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PostPosted: Mon Aug 12, 2002 2:32 pm 
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Nothing dodgy about them. They're engineering formulas. The table is exactly that, calculated values, intelligent guesstimates based on formulas on fan airflow and noise. Sort of like, if all fans behaved ideally, then... Clearly explained in the article and the intro, with caveats about their real-world accuracy. That -3.1dB figure is not realistic, even if scientifically correct. <br>

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