am I missing something?
L = 10(lg P2/P1) dB

ie 3dB more is double, and 10dB more is 10 times more the intensity/Power.

+3db doubles the sound intensity. +10db doubles the perceived volume.

geevade is correct. By definition, the decibel scale is such that +10dB is x10 times the quantity (sound intensity in this case), not x2 like Tom's says.

I'm not sure where you (abc) got the idea that +10dB is twice the perceived volume. If it can be quantified at all, perceived volume is considered logarithmic in intensity, and since the intensity scale is calibrated to have the hearing threshold at 0dB, it is should be exactly proportional to the dB rating. So actually x2 the dB would be x2 the perceived volume.

I stopped reading this article when I realized the writers don't understand noise at all and couldn't even bother to check their facts.

Good article. Few notes:
1. If the springs in the GUP solution made the upper surface of the HDD pess firmly against the upper (Al) plate of the cage, doesn't that mean the vibration is transmitted to that plate as well, negating the dampening effect of the springs? How could it pull such good results?! Can the author comment on that please.
2. I think the comparison would be more realistic if -instead of throwing it on a styrofoam on a workbench- the raptor's noise was measured in a cheap B-brand case , with the GUP cage inside that cheap case, and then with the HDD in the Trex case. The results would be simimlar to the real experience of the user. The chassis could have amplified the vibration, on the other hand the closed case could dampen the noise, who knows what the end result would be?
3. It would have been nice to compare both products to some popular cases that sport a plastic or rubber tool-less mounting for the HDDs claimed to reduce the niose e.g CM Storm Sniper or HAF 932..The latter case sells for appriximately the same price of the GUP cage (case = HDD cage!), so comparing them would have given true impression about their value.
4. Have the author considered recording the noise with a sensitive mic to let us hear the noise and decide for ourselves how niosy 40 dBl is..This is just a suggestion..
Thanks

For sound pressure, the formula is L=20(log P2/P1) dB... in other words, +6 dB doubles it and +20 dB is 10 x intensity.

Alright Holy-Fire you are wrong, kinda. +10dB is 10x the intensity. However, You are wrong about the perceived volume. Tom's (and ABC) has it right, at least for the purposes of hard drive silencing.

"Another consideration which prompts the use of powers of 10 for sound measurement is the rule of thumb for loudness: it takes about 10 times the intensity to sound twice as loud." ()

That is what this article is about. Perceived loudness. Who cares what the intensity actually is. Quit nit-picking and read the article for what it is worth. A +10dB increase means a particular sound will seem twice as loud.

Don't let 'em get ya down Tom's!

Ok, they took out my link to that quote...

http://hyperphysics.phy-astr.gsu.e [...] nd/db.html

chjade is correct. While +10dB represents 10 times the sound power, it is perceived by humans as being twice as loud. +3dB of noise is barely detectable by humans.

how about using sone, if talking about perceived loudness. dB is about the magnitude relative to a reference level. Perceived loudness also depends on the frequency of the noise (and age e.g. we're the most sensitive at about 2kHz.

Because, the sone is not an SI unit, not widely used, many people don't understand it or know what it is, but most importantly...

...it doesn't matter.

This is not a technical white paper addressing the worldwide consortium of hard drive manufacturing acoustical engineers (WCHDMAE, LOL). This all is irrelevant. All people need to know is that this particular method makes your hard drive seem about half or about a third as loud.

Stop thinking so much!

Thanks for the feedback!

@avatar_raq:

1) The aluminum plate comes with a heat conducting surface coating, which prevents vibration to transmit to the cover.

2) Our approach of running the old Raptor on styro pads reflects the lowest possible noise. I agree, using a case would probably be more realistic.

3) I am not sure when we'll do something similar again, but we'll look around some more once that is the case.

4) Not considered, sorry. Since we can't spend unlimited time on this type of product reviews it will be hard to do it all.

Correction: There is no head conductive coating, but a few pads that you install in between the drive and the aluminum cover.

Get an SSD drive if you want quiet/silence or speed. Old Raptors were noisy, VelociRaptors are fairly quiet by comparison.

"meaning that 40 dB is double the sound pressure of 30 dB, 50 dB is twice as much as 40 dB, and so on".
To those who talking about loudness, read the quotation above once more. Do you find any trace of loudness being mensioned? I don't. Thus the author doesn't know what he is talking about. And it doesn't matter if the article is for general audience or for engineers. Such mistakes shall not appear at all. Obviously author either does not know what dB is or the difference between the sound pressure and loudness.

Thanks Pschmid. Appreciated.

I have two GUP Smart Drive 2002C's in use (a better model but same concept). They are brilliant! Hard drive noise is not an issue if your other components are loud... but if you're a silence loving man and your other components are silenced then Hard drive sound proofing is the next step. I have both GPU and CPU on water cooling, use an Enermax quiet PSU and an SSD as my boot OS. The GUP'S are used for a 1.5TB Seagate and 300GB Velociraptor. The only drawback I see is using the 5.25 Inch Drive bay for a 3.5Inch drive.... but they run cooler quieter so its worth it. PC weighs a lot more though... these things are heavy.

The dB scale is a measurement of relative POWER, based on the exponent of ten. One sound that delivers twice [2 times] the power of another would be 10 x log(2) = 3.0dB louder. A sound that is quintuple [5 times] the power of another is 10 x log(5) = 7.0dB louder.
The "37dB" figures shown in the article are relative to the amount of acoustic power required for a human to hear ANYTHING, which is "0dB". That's assuming an environment free of any extraneous noise such as refrigerators, street noise, air systems in homes, wind noise, etc. In other words, you'd probably have to find a dry cave in the middle of nowhere to get near that sort of audio level. Otherwise, you're lucky if it's in the low 30's.
The maximum power that the ear can handle without real pain is 120dB, or ten to the 12th power higher (1,000,000,000,000). As once was explained to me, it's the difference between two fleas making love and two elephants in the same act.
But there's a real difference between "acoustic power" and perceived "loudness". It's related to the frequencies involved as well as the actual power, with the highest and lowest frequencies seeming to fall faster as actual acoustic power is reduced. Not surprisingly, we're more sensitive to the frequencies in the middle of the audio spectrum, so a squeal at about 1,000Hz is going to be more annoying than an equally powerful noise at 20 Hz or one at 15kHz. The latter was often produced rather strongly from old CRT televisions, but seldom noticed by the general public.
Most acoustic measuring devices come with filters to simulate the sensitivity of the human ear to various frequencies, and I'm sure that these were used for the measurements in Tom's article.

On a related note (no pun intended) a little insulation foam strips strategically located in a computer case can do wonders to reduce the internal noise from becoming external noise. The large-area case sides can radiate noise like a large loudspeaker, so a thin layer of silicone on these slabs of steel, aluminum, or plastic can deaden the acoustic properties of the cases without adversely affecting the cooling of the system. And a lower-power CPU can also mean a slower, quieter fan to keep it cool. Just a thought.

Hey Patrick,
I'm wondering what kind of sound deadening material they use in the 3RSystem? More like how does the texture feels like. Lol might sound like a stupid question.

It's just that most of the sound proof materials that I've worked with (for other projects, not building PC) easily absorb heat, but dissipate it slower. So is there any sign of hotter or faster heat build up during your test with the 3RSystem case? My average room temp. is 27c, up to 30c when my PC is on, on to 35c during hot days