Air and heat

[Shadowknight]

http://forums.anandtech.com/messageview ... TARTPAGE=2
It's interesting how some people have no idea what they are talking about. Apparently, this guy believes that 1) aluminum is equal to steel in terms of resonance, and 2) that aluminum metal makes a huge difference in terms of internal temps.... Anybody else want to step in with why this is wrong?

[sthayashi]

I suspect material DOES make a difference, but not so much between steel and aluminum. The case type I have in my mind are acrylic cases. Though since I've never owned one and decent reviews are few and far between, it's more of a guess than anything else.

[~El~Jefe~]

lol yeah no clue what they are saying.

the 3rd poster on there goes on to say about cheap flimsy cases being worse for it...

actually, the cheaper and crappier the metal the less it resonates. thin doesnt help, true, but a nice piece of junk just thunks and can hold a note when struck. check out my antec SLK 3700BQE case. its made from the worst pos asian steel money could buy. it is thick though which helps. aluminum resonates not only be cause it is less massive, but because it is also much more pure, like a musical instrument.

however, a solid brass 4mm case would probably resonate not much.

[Ralf Hutter]

Anybody else want to step in with why this is wrong?

Why bother? You'd have an easier time proving that there is a God.

Apparently, no matter how much evidence there is to the contrary, the "aluminum cases cool better than steel cases" debate will never end. I usually don't even waste my time replying to those threads any more, but I just had to reply to that guy's particular post.

[Shadowknight]

Yeah, apparently the guy's still writing responses which shows he doesn't know what he's talking about. At this poing, I'm just going to let it go. I have better things to do than argue with someone who doesn't get that it really makes no difference in the heat transfer without direct contact. Oh, and now apparently he blithley assumes aluminum is as quiet as steel

[Al]

Oh, and now apparently he blithley assumes aluminum is as quiet as steel

Yeah just had a go at straightening that one out... Wonder how he'll take it.

Al

[Bluefront]

Ok....explain this to me. Here at SPCR we advocate quiet parts for your computer, slow-speed, rubber-mounted fans, of the quietest brands. We push quiet hard drives, decoupled, maybe in a silent enclosure. We suggest low-power, maybe under-volted CPUs that can be cooled with minimum airflow, minimum fan speed. We push the quietest possible PSUs, some even fanless. We line our cases with acoustic foam padding of all sorts. On and on.....

So where is this horrible resonance/vibration supposed to come from, should one decide to buy an aluminum case?

IMHO.....the type of metal used in your quiet computer, assuming every quiet measure has been followed, is the very last thing to raise your noise level. To me, you are wasting your time/breath to tell someone his expensive aluminum case will be noisier than some dull-looking steel/plastic Antec case.

Humm....I wonder if my noisy aluminum computer is still running? Sure can't hear it.......

[IsaacKuo]

I agree--I could never understand the fascination here with so-called "quiet cases". A case makes no noise of its own!

[Rusty075]

.the type of metal used in your quiet computer, assuming every quiet measure has been followed, is the very last thing to raise your noise level.

The big point there is, "assuming every quiet measure has been followed". If you had a case that was made from a material that absolutely, possitively could not resonate, then many of the steps that we take here to reduce noise could be skipped. If it wasn't for resonating enclosures no one would be decoupling their HDD's or mounting their fans with foam plugs. So what's the logic of starting yourself off at a disadvantage? Particularly when the noise disadvantage doesn't gain you any performance benefit. The only reason to select a thin aluminum case is aesthetics, but you need to realise that if silence is your goal, then that decision makes it harder to succeed.

At some level the opposite of Bluefront's postulate is true: as everything else gets quiet, the noise produced from case resonance often becomes the hardest to get rid of, so the material becomes more important. It's at the extremes where case selection doesn't matter. If your case is full of screaming fans and HDD's that vibrate like a coin operated rotating bed in a Niagara Falls motel room, then it doesn't matter if the case resonates - you'll never hear it over the racket. Likewise, if nothing in your case makes any noise, or any vibration, then the case doesn't matter either. It's in the middle where it makes a difference.

And yes, calling a case "quiet" is an oxymoron. But referring to cases as "less likely to amplify, and/or more likely to reduce the noises being produced by the rest of the components in the system" takes up a lot more room.

I agree with Ralf on this one...if someone really wants to argue in the face of solid evidence to the contrary, and without any evidence on their side, then just let them go on believing whatever they want. No point in even trying.

[Bluefront]

Well......I guess nothing in this aluminum case makes noise then.

I can touch any part of the outside of the case and not feel any vibration. To actually hear anything I have to get close to the single exhaust point at the rear, or lay on the floor to hear the noise at the bottom of the oak intake chamber the computer sits on.

Look... this case is an AMS server model made of 2mm aluminum. Nothing about it is standard SPCR stuff. About the only thing I got from SPCR, that I applied to this case, are three Yate Loon fans, located from a post about cheap Yate Loons at Comp Geeks. There is a big acrylic window on the left panel, and some blue lights....certainly not SPCR recommended. I'm using a slightly over-clocked Northwood P4-3.2, cooled by a Silverstone NT-01. The fans in the case are controlled by a LIS2 auto-fan system.

Like I said....almost nothing SPCR recommended. And yet it is an extremely quiet system, and extremely clean running, using two big real air filters. And what does this mean? It means you, anyone, can build a quiet system without following SPCR guidelines. And that means you can use an aluminum case, if you so choose.

You just have to use your head....ask some questions, and not be afraid to do things differently from the "norm".

[Rusty075]

Look... this case is an AMS server model made of 2mm aluminum.

The only reason to select a thin aluminum case is aesthetics, but you need to realise that if silence is your goal, then that decision makes it harder to succeed.

2mm aluminum is hardly typical. Try the same setup in a conventional aluminum case. It isn't so much a matter of the material, as it is the way it's used in the typical. The aluminum has to be thicker to equal the same anti-resonance qualities as a much thinner steel case would have.

I'm not really sure where you're going with the "standard SPCR stuff" bit, if anything the steps you've taken to silence that system are above and beyond the degree of complexity that most people would attempt. And since when is there anything "unrecommended" about windows or lights? They don't make noise.

[Bluefront]

What I mean is the impression one gets, reading many of the posts on SPCR. Like "use steel cases", use this HSF, use this PSU, don't buy from this mfg......

It's like there is only one way to achieve a quiet computer, and this is it. It's just not true. There are many ways to skin a cat....and to build a quiet computer.

[Rusty075]

I'd agree with that. (the "more than one way to build a silent pc" part...I've only found one good way to skin cats. )

Part of the problem is that the response is directly related to the question, and the question is much more often, "what heatsink should I buy?" than it is, "here's my new idea on how to manage airflow, what do you think?" The easy question gets the easy answer, particularly when that question has been asked 4278 times.

[Bluefront]

You certainly are right about "simple questions get simple answers". I think that is directly related to the difficulty one has, trying to use the "Search" feature to find a simple answer.

I swear I almost never can find a simple answer to anything. Search will find 300 posts, none of which answer my question. Maybe my questions are too difficult......

Ok.....many posts here are lame. "what's the best 120mm fan" I see that post every two days.......

Then I see "What case is best, aluminum or steel".......

[~El~Jefe~]

in quiet cases the case acts as a dampener for the left over sounds. it is not a silent case at all without the extra layer of dead crap steel over it.

to open air its much noisier even at low decibel ratings. Aluminum can AUGMENT sounds or at least, not block them much at all.

although, I think it's a great feat to make one, and Al cases are 1000X more fun looking and have many more nifty light options....


i miss my bling... next system is mega bling.

[BrianE]

check out my antec SLK 3700BQE case. its made from the worst pos asian steel money could buy.

I doubt it - that's probably the super cheap generic case I bought to transfer some old parts into... the side panels remind me of aluminum flashing!


My $0.02 is that I agree that construction and design are greater factors than material alone, and that people tend to expect too much from a computer case... I've been visiting more computer stores recently and it's surprising how often you hear people looking for some kind of "really quiet case they heard about".

[pony-tail]

The quietest computer I have owned was in a Lian Li aluminium case .
But ! - the system was a low powered (dual PIII ) completely fanless system
The claimed heat transfer of aluminium is there - but it is minimal so much so as to be insignificant (2c in the case of this machine with the CPU temp unchanged )
As for resonance I have seen steel cases both better and worse than a lian Li - design and quality of build play just as important a role in this as material.
For reference my current systems are in either Inwin V528 cases or Antec sonata cases (3 of each )except our current server which is a Soltek cube (SFF) and was pretty quiet out of the box (XP athlon-Nforce integrated video) but low spec by todays standards -