How accurate are product specs?
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How accurate are product specs?
I was looking at the Fractal R2 Silent 120MM Black out 120 mm fan. In the specs it says that its CFM is 66 and that its DBA is only 18 at 1300 RPM. I find that really hard to believe. How accurate are product specs usually? I also saw the Akasa Black Apache 120MM fan with 57 CFM at 18 DBA also at 1300 RPM. I was trying to decide between the 2, but like I said its hard to believe what is right and what is not.
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quest_for_silence
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Re: How accurate are product specs?
falcon26 wrote:its hard to believe what is right and what is not.
When something sounds too good to be true, it is.
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quest_for_silence
- Posts: 5275
- Joined: Wed Jun 13, 2007 10:12 am
- Location: ITALY
Re: How accurate are product specs?
Just to add a somehow meaningful detail to my short answer: I think the Akasa Apache Black (FN058) is identical to the Akasa Apache with the camouflage colors (FN057).
I owned that fan and in my experience it was subjectively louder either than the Scythe Slipstream PWM SY1225SL12LM-P, measured at 24-26dB around 1300rpm by SPCR, or than the Scythe Slipstream M SY1225SL12M at full speed (you may check by yourself the relevant SPCR testing, but that latter was measured at 28dB at about 1200rpm).
The bottom line is that: a) nowadays, no commercially available 120mm fan may produce just 15/16dB at 1200/1300rpm (with such an airflow!); b) to trust any measure, you need a common coordinate system, namely the same, proven, trustworthy measurement system; c) at 15/16dB a 120mm fan usually can't past 1000rpm (1100rpm in the most favourable case, as the Scythe/Nidec Gentle Typhoon, which was measured by SPCR at 16-17dB/1100rpm); d) the Sound Pressure Level isn't all that matter, noise-wise: the relevant frequency spectrum help us to better know how much noticeable a sound will be to a human ear.
I owned that fan and in my experience it was subjectively louder either than the Scythe Slipstream PWM SY1225SL12LM-P, measured at 24-26dB around 1300rpm by SPCR, or than the Scythe Slipstream M SY1225SL12M at full speed (you may check by yourself the relevant SPCR testing, but that latter was measured at 28dB at about 1200rpm).
The bottom line is that: a) nowadays, no commercially available 120mm fan may produce just 15/16dB at 1200/1300rpm (with such an airflow!); b) to trust any measure, you need a common coordinate system, namely the same, proven, trustworthy measurement system; c) at 15/16dB a 120mm fan usually can't past 1000rpm (1100rpm in the most favourable case, as the Scythe/Nidec Gentle Typhoon, which was measured by SPCR at 16-17dB/1100rpm); d) the Sound Pressure Level isn't all that matter, noise-wise: the relevant frequency spectrum help us to better know how much noticeable a sound will be to a human ear.
Re: How accurate are product specs?
noise spec is most of the time way too optimistic except for very reputable brands such as Noctua, Sanyo-Denko, Delta and few others.
Re: How accurate are product specs?
Ignore CFM and decibel ratings on fan packaging.
Read credible review sites' testing results.
The only reason fan companies get away with lying is because no one has bothered to sue them.
That's the conclusion I've come to. While there may be a select few who post accurate specs, proof is really needed to be sure.
Read credible review sites' testing results.
The only reason fan companies get away with lying is because no one has bothered to sue them.
That's the conclusion I've come to. While there may be a select few who post accurate specs, proof is really needed to be sure.