Quiet Case? Not so Quiet Case?

[Talal Itani]

Hello,

I am putting together a PC. I will go with a quiet power supply and quiet
fans. Does the case influence the noise level? I mean, are they quiet
cases and not-so-quiet cases? Thanks.

T.I.

 

[Darklight]

Hello,

I am putting together a PC. I will go with a quiet power supply and quiet
fans. Does the case influence the noise level? I mean, are they quiet
cases and not-so-quiet cases? Thanks.

T.I.

the answer is yes a friend of mine just built a new pc with a quiet case and
fans and it is quiet

 

[Joel]

the answer is yes a friend of mine just built a new pc with a quiet case and
fans and it is quiet

Actually the answer is YES and NO depending on the speed of the fan, and
there are some quiet but very powerful fan that can make very loud noise not
because of the bearing but air flow.

Yup! a great amount of air go through a small 2-3" hole can make a quiet
fan sounds like jet engine <bg>. Here, I have 2 of those suckers and I have
to spend extra $$$ to buy a Fan-Controller to reduce (control) the speed to
reduce the noise.

 

[UCLAN]

the answer is yes a friend of mine just built a new pc with a quiet case and
fans and it is quiet

???

Beside the fans (which are not really part of the case), what makes
the case "quiet" ?? If low speed/airflow fans are used, what makes
one case noisier than another?

 

[Noozer]

???

Beside the fans (which are not really part of the case), what makes
the case "quiet" ?? If low speed/airflow fans are used, what makes
one case noisier than another?

A poorly designed case can introduce rattles and vibrations that a good case
won't. Also a good case will provide unimpeded airflow for the fans. I've
seen many cases where the rear fan had more metal over it than openings.

Also, there are several cases that provide rubber bushings to isolate the
case from the vibration of drives and fans. I've even seen a case where the
hard drives are mounted in "rubber bands" with no solid connection to the
case at all.

 

[Paul]

???

Beside the fans (which are not really part of the case), what makes
the case "quiet" ?? If low speed/airflow fans are used, what makes
one case noisier than another?

Resonance and damping. A heavy steel case may help a bit. Rubber mounts
for fans or drives may help a bit. But it is pretty hard to predict which
products will be effective. And each person's perception of noise can be
different (some people are bothered by certain kinds of noises, more than
others).

There can be unit to unit variation as well. Like a side panel that doesn't
fit well, and resonates with some internal vibration.

The choice of vent hole type can make a difference. If you mount a fan
next to a "cheese grater" type of vent cover, you may get more turbulence
noise than from a wire grill.

Some cases use serpentine air paths, to baffle noise. Or place the air
intake, near the bottom front of the case. All in an effort to avoid
a direct path for sound waves. Again, that doesn't help, if the case
is still basically transparent, and there are other ways for the internal
noises to escape.

It is possible to use sound absorbing mats inside a case, but that also
tends to drive up the internal operating temperature a bit.

The best way to avoid noise, is to cut down on the number of things that
rotate. This is an example of a very expensive case ($600), that dumps internal
heat by using heat pipes. The heat pipes connect to the outside of the
case, so the case functions as a heatsink.

Zalman TNN-300
http://www.silentpcreview.com/article302-page1.html

And if you insist on using high performance computer parts (130W processor
plus two 8800GTX, for example), then it is going to be next to impossible
to keep a computer case for that hardware, quiet.

Paul

 

[Ken Maltby]

Resonance and damping. A heavy steel case may help a bit. Rubber mounts
for fans or drives may help a bit. But it is pretty hard to predict which
products will be effective. And each person's perception of noise can be
different (some people are bothered by certain kinds of noises, more than
others).

There can be unit to unit variation as well. Like a side panel that
doesn't
fit well, and resonates with some internal vibration.

The choice of vent hole type can make a difference. If you mount a fan
next to a "cheese grater" type of vent cover, you may get more turbulence
noise than from a wire grill.

Some cases use serpentine air paths, to baffle noise. Or place the air
intake, near the bottom front of the case. All in an effort to avoid
a direct path for sound waves. Again, that doesn't help, if the case
is still basically transparent, and there are other ways for the internal
noises to escape.

It is possible to use sound absorbing mats inside a case, but that also
tends to drive up the internal operating temperature a bit.

The best way to avoid noise, is to cut down on the number of things that
rotate. This is an example of a very expensive case ($600), that dumps
internal
heat by using heat pipes. The heat pipes connect to the outside of the
case, so the case functions as a heatsink.

Zalman TNN-300
http://www.silentpcreview.com/article302-page1.html

And if you insist on using high performance computer parts (130W processor
plus two 8800GTX, for example), then it is going to be next to impossible
to keep a computer case for that hardware, quiet.

Paul

Well there is watercooling.

For the air-cooled case there can be another issue, that
is where the airflow itself induces a resonance somewhere.
I have a very quiet Antec Sonata II case but it had a odd
sound whenever I had the front cover/door at a certain
position. ( I guess computer cases should be in the Brass
section not the Woodwind.)

Luck;
Ken

 

[kony]

Hello,

I am putting together a PC. I will go with a quiet power supply and quiet
fans. Does the case influence the noise level? I mean, are they quiet
cases and not-so-quiet cases? Thanks.

Yes

Recognize that ideally, the key to getting a system as quiet
as possible is to not go overboard. Keep it cool enough but
not more than that. This means larger low RPM fans and
where they are placed and how many you need will be dictated
by the case design.

The case may have stamped metal grills that impede airflow,
or it may have insufficient rear exhaust and need a front
fan for good flow rate (or higher speed rear fan). It is
better to have an additional fan or two to keep them all at
lowest RPM possible (without overheating) but not to have
fan mounts you won't use that create short loops robbing the
system of the airflow over the normal path it was supposed
to take. Thus unused fan mounts should be blocked off, if
not the front intake area. Similarly a front (plastic, or
metal faced sometimes) bezel may be better or worse at
intake (area) but if you have a front fan you don't want a
gaping hole as the fan noise directly exits the case so it
is more easily heard by the person in front of the system.

If the system were on the floor, below or beside a desk then
much can be forgiven, that alone will reduce perceived noise
levels.

Cases too thin may vibrate, particularly with cheap poorly
balanced fans in them. Fan mats can help absorb vibration
but better to have case that doesn't vibrate either. This
includes metal thickness, folds in the metal, cross bracing
above a certain size, # of rivets per joined area, even the
way the side panel is attached.

One of the easier choices to aid in lowering noise is to get
a case with a rear 120mm fan. One with a low default RPM or
used with a fan controller. Next have ample front intake
area and resist the urge to add any more fans unless the
system is particularly high heat generating as many systems
can be cooled fine with only the PSU exhaust and one rear
fan at low RPM - "IF" the air intake and exhaust areas
aren't overly restrictive.