Misplaced faith in noise figures.
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  1. #1
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    Misplaced faith in noise figures.

    A thread at SPCR commenting on hard drive noise measurements at Storage Review.

    These remarks apply equally to published noise figures for fans. Beware of them.

  2. #2
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    While the topic is a valid one, what I see there is a _fanboy_ throwing an "I wanna lollypop!" tantrum because his favourite brand wasn't at the top.

    And the straw man he brings is just that: a straw man. Basically his logic is "but the Samsung was 1 degree cooler, so it must be the quietest too!" Which, sorry, is just bogus. It's so bogus, it pegs my bogon counter hard.

    The argument about how SPCR measures is a valid point, except personally I wouldn't be that quick to dismiss the high frequencies. Regardless of what the A (as in dBA) scale says, you may not hear them the loudest, but they are the most annoying.

    And it's not a case of "bah, they exist only at a few mm like in SR's test." You _can_ hear them even with a closed case from 2m. I hear the soft high pitched whine of the computers at work, coming from the Maxtor drives. (It disappears when you put the HDD to sleep.) It is audible and being high pitched it's annoying.

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    That is exactly the point: you can hear hdd's and fans quite clearly, but the noise produced by the quieter ones is very difficult to measure accurately.

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    As an individual with above average hearing, I find most noise readings to be a joke. Some reviewers hold the meter 5 feet away from the device, others shove the thing 4" up the printer port. I value quiet components, but those values rarely carry any water. I prefer the reviewers opinions. They will tell you if it's quiet or not, and I prefer when they use relative terms. For example, some people say it's quiet in a case with 5 other fans going. It's not the best measure, but at least I know their point of reference. From there I determine whether to disqualify their opinion.

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    Originally posted by DanceMan
    That is exactly the point: you can hear hdd's and fans quite clearly, but the noise produced by the quieter ones is very difficult to measure accurately.
    That may be so, but I still prefer _some_ measurement, however flawed it may be, to pure fanboy preconceptions.

    He starts from the preconceived notion that Samsung _must_ be the absolute best in all areas, and the only good measurements or sites are those who confirm his prejudice. Measurements be damned, he knows the One True Result already.

    Which is dogma, not a useful scientific result.

    Is SR's measurement relevant in the real world? Maybe or maybe not. It's still an unbiased measurement which is done in equal conditions for all drives.

    At the very least, it beats relying only on the manufacture's figures. Which might as well be pulled out of the *** by the marketting department. Or at least are measured differently by each manufacturer, making an apples-to-apples comparison impossible.

    Does SR's measurement favour higher frequencies? Hell if I know. I wouldn't mind if it did, though, because I can hear high frequencies very well.

    I don't think it does though. Here's the fun part about actually knowing some physics: different frequencies aren't atenuated that differently in air. If there are a lot of high tones at 5mm distance, you'll have roughly the same percentage of them at 5m too.

    So basically all else being equal (e.g., same mike) the only difference between measuring at 5mm and at 5m is the dB level you read. But as long as it's measured at the same distance for all drives, the sorting by noise level stays the same.

    Briefly: If drive A had 41 dB up close and B had 40, at a much larger distance A might have 21 dB and B might have 20 dB. But A does stay noiser than B and that's that.

    Would those high frequencies be muffled by a closed case? Maybe or maybe not. Depends on the case. An aluminum case tends to transmit those high frequencies a lot better than a steel one, for example. And those of us having an open case also have no such atenuation.

    Either way, it is one unbiased measurement. Whether it's the best measurement or not, I wouldn't know. But I'd still put more faith in it than in a fanboy's childish tantrums.

  6. #6
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    He starts from the preconceived notion
    No, he starts from the listening tests of many pairs of ears, who've posted at the forum. It's a consensus reached by people not afraid to use the five senses God gave them, six if you count common sense. It's come from direct comparison of the drives they own and use.

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    I'll still put my faith in something actually measured than in fanboys jumping on the latest fashion bandwagon.

    There was a good story about people and their senses. It's called "The Emperor's New Clothes". Read it sometime. Fascinating and insightful story, to say the least.

    Except that story did get one detail wrong. In the story you can safely assume that the people were just saying that they see the clothes. You know, to avoid having to explain it to the Emperor's new guards, in the comfort of the Emperor's new dungeon.

    Reality is sadder than that. Give people the idea that they're somehow inferior if they can't see the clothes, and they'll squint and stare until they genuinely believe that they see the clothes. Because otherwise they'd be inferior. And they don't want that.

    A lot of "but my senses tell me otherwise" bull**** and flamewars is just that: The Emperor's New Clothes.

    Actual examples include "you're not an audiophile unless you can hear how a screechy clicky noisy vinyl record sounds better than a CD." Or "you're not an audiophile unless you can swear that transistors distort sound more than tubes do."

    Give people the idea that they're only acceptable in the elite(ist) circle if they too hear something that's not there, and they'll start hearing it too. You could probably even make them genuinely see Elvis dancing with the Yeti on top of a flying saucer, if you managed to convince them that their social acceptance depends on it.

    The fact remains, on SPCR it's _fashionable_ to ***** and moan about Seagate drives. (Just like on Slashdot it's fashionable to ***** and moan about Windows.)

    I don't know how that started. Maybe someone was pissed off that Seagate didn't send him a free drive to review, or something. Or someone was pissed off at SR as a site and just needed some reason to ***** about them. But I can see how lemmings would start jumping on that bandwagon.

    The fact remains, Seagate drives _are_ quiet. Not just idle noise, but seek noise too. If I start a defrag on the Maxtor at work, the whole office hears it. If I start one at home, I can barely hear it with an open case and most fans disconnected. (Well, obviously except the 12 dBA fan on the CPU and the 18 dBA fan on the PSU.)

    Are the Samsungs more quiet than that? Could be. Actual measured noise levels don't seem to confirm that. But ok, I'll take that on faith. Let's say Samsungs _are_ more quiet.

    But we're already in the range which doesn't justify the kind of "Seagate sucks and SR blows" childish tantrums.

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    Ok, lemme try to explain that in less trollish terms.

    Subjective perceptions and senses have this funny property: they're distorted to hell and back if they'd get in the way of someone's belief. Not only his. Mine too.

    Hence:

    1. I tend to not even consider those perceptions in a post which looks like a tantrum.

    "You! Yes YOU! Click on 'sort' NOW! WTH is this crap?!? Why isn't Samsung at the top???" Not an exact quote, but you get the idea. Dunno, anything on those tone gives me the idea that it just _might_ not be completely impartial.

    2. While I'm willing to accept subjective perceptions as a scientiffic fact, I'll want a double-blind test.

    It _could_ be that measurements with instruments miss something that the ear does pick. Or that our whole A scale missed something important. It's not impossible, and in fact it's not even crazy.

    But to prove that, you have to first get rid of the distorted perception I've mentioned before. Get as much of it out of the equation, as humanly possible.

    Have a "name the quietest of these hard drives", where they can listen to the drives but noone knows which hard drive is from which brand. Not even the ones conducting the test, or anyone who comes anywhere _near_ the test subjects.

    If _then_ everyone still says that brand A is quiet, and brand B sounds like a circular saw, now that I'm willing to accept as a fact.

  9. #9
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    The fact remains, on SPCR it's _fashionable_ to ***** and moan about Seagate drives.
    Hardly, considering the Seagate Barracuda IV 40G was/is their reference quiet hard drive since the site started. I think one of the Samsungs now shares that position.

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