SPCR

I'm in the quest of dampening my case and noticed a sound section over at Mcmaster's (although I don't think I will order anything from them).

Are dampers even necessary for aluminum cases? I don't think I really notice any vibration in my case unless it's there and I just don't know about it.

So what's the most critical? Or are they all equally important?

No easy answer. I suspect every case, every setup, acts differently depending on its construction, the type of metal, the thickness of the metal, the internal bracing.....not to mention the internal components you add. You just cannot tell in advance what will happen when your setup is complete.

I try to use different sound dampeners, a barrier layer covered with an absorber layer if possible. The biggest factor is how much internal space is available......you must leave enough space for proper airflow.

A forum such as SPCR is valuable, because you can see what others have done. Copying a successful design is easiest. If you use a new or different case from the norm.....you're on your own Buster.

My experience is that aluminum can benefit greatly from damping, i.e. putting a heavy layer of flexible material on the case covers. It's amazing how resonance can make sound - it's best illustrated if you try tapping the case ever so lightly in the "dead" of night.

Secondly, you will have airborne noise, from HDDs of course, but mostly from fans. Here the case material doesn't matter too much, but rather how direct a path the sound will have towards your ears. Again my experience is that shutting off direct paths is the most effective measure - and sound absorbers applied have minute effects on sound, I've read somewhere that you would need really thick insulation to do the trick. Much better is to make sure you have the proper air paths, so you can undervolt your fans, the best noise absorber there is.

/datapappan

Hmm I think I should try to get a combo of the three then. I didn't realize each were of such great importance.

My V2100B already has foam on the sidepanels and top of the case. Should I remove that stuff and replace it with my own foam?

barrier
and weight of material/density

~El~Jefe~ wrote:barrier
and weight of material/density

?
Sorry can you please explain?

It should be fairly easy to determine if damping will help on a metal panel. If pressing your fingers or hand on a panel reduces or changes the noise and vibration, damping will probably make a difference.

Almost any metal will be opaque to higher frequencies. Unfortunately most noise in a PC is at a relatively low frequency. The base "noise" of a 7200 rpm hard drive is at 120 Hz (7200 divided by 60). In music 120 hz is moderately low. The hard drive will also produce harmonics at higher frequencies but they will be lower in energy. I think the harmonics are what make a hard drive whine.

Low frequencies tend to have more energy than high frequencies so they cause materials to vibrate. Putting a 1/2 inch thick piece of foam won't block the sound of a subwoofer but will block the sound of a tweeter. That's why you have to either add mass, isolate (suspend), or stiffen panels to reduce vibration.

definitely go with a combination of all 3 where space permits. Each of the 3 components serves its own distinctive purpose. On the first page of that mcmaster catalog is an explanation of how each of those 3 contributes to minimizing your perception of sound.

it is generally regarded that aluminum cases do vibrate/resonate more than their steel counterparts. With that in mind, and if I could only choose one I would go with a high density/thick piece of dampening material. This would serve a dual purpose of blocking sound and keeping it inside your case as well as sturdying up your case to reduce resonance.

I myself am going with a composite of 3 layers...a thin dampening sheet, a barrier sheet and a top layer of foam on the top, bottom and left side and then just the dampening and barrier on the right side, back and front. I have yet to come up with the money to order anything from them but thats the plan. I have also seen some cheap automotive stuff that combines the barrier and foam into one piece if you're looking for something local and for a lower budget, but i'm not sure how good they would perform.

~best of luck to you

harmonics would make that whine. it must be a few things, maybe the ring of the metal objects, maybe some sort of pure tone that is emitted.

maybe it is a Shinma.

Into the darkness, Shinma!

That would be phat.

Anyone ever fully analyze what the notes and noises are from a hd?

I agree with snowman...

I've been heavy into car audio much longer than I have PC tweaking, and making lightweight resonant material more "massive" is a huge key in the car audio world to stop rattles. etc, as well as squeeze as much volume out of the system as possible.

Like another post said, all materials have a sympathetic resonance frequency, and that can come as easily from a musical tone or from a Nforce 4 mobo fan. It's interesting to see the trend come to the enthusiast PC world, but I'm not sure if the differences will be as dramatic as it would be in car audio, since the sound pressure and decible levels are so different.

For example, my car system has 4 10" subs w @ 400 watts to each running infinate baffle (using the car trunk as the enclosure), and my front component speakers have 300 watts going to each side, so there's a lot of sound pressure level being created, and with it, sympathetic resonance and rattles. I got rid of them by using a lot of adhesive damping mat (Scoshe Accumat) on both the interior car body and interior trim panels, as well as using expanding spray foam to fill frame cavities and create stiffer trim panels.

The result is that, with the windows closed, standing outside next to the car you can hardly hear any bass at all (mainly comes through the windsheild glass). But inside, you can make your arm hair move if you want... but I like to keep my hearing, so I rarely do that.

That said, coming back to the PC world, I think you could benefit slightly from using deadening methods, but maybe more from sound wave absorption methods, etc., simply since the physical vibration of a PC case is so much less than, for example, the sound pressure level that can make a car roof flex.

Also, most of the noise in a PC is high frequency, not midrange/bass tones, so it has shorter wave forms, and may be able to be dispersed/muted more easlily with abosorption material (some car audio competitors use dash carpets to help reduce relflection from tweeters... the carpet fibers help to "trap" the high frequency waves).

Sorry for the long post, but I just drank a mug of espresso.