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how much sound from a fan????????

D

dbuttcheek69

Senior member
i was just wondering, when buying a case fan they are rated in decibles. what type of decible level would be a silent one? alot of fans are around 25 db. how loud is that? in english

i didnt word it really well but u prolly know what i mean

thanks alot
 
Im tryin to build a super quiet computer. I have a silent Zalman psu, but how high in the db range for a fan should i go without it being significantly loud?
 
Originally posted by: dbuttcheek69
Im tryin to build a super quiet computer. I have a silent Zalman psu, but how high in the db range for a fan should i go without it being significantly loud?
Click to expand...

I would say anything under 30 dba.
 
Dear lord, 30db is what most people are trying to get rid of... and I don't mean the hairdryer crowd. I've replaced 26db fans people hate to the 19-21-ish range. 3db more means twice as loud, if you're looking for quiet, since some people have different definitions.
 
There are some things to consider about dB ratings, assuming they are accurate. The noise consists of a combination of wind-turbulence and motor-noise, bearing noise or vibration. It is the motor-related noises which are most annoying, and the sound of "rushing air" is to be expected with high throughput, which improves cooling.

Then there is the issue -- assuming you choose fans with no motor-noise -- whether the fan is to be located at the front or the rear -- or even the top or the case. You are not likely to hear "wind-turbulence so much if it is at the back side of the case. If the fan is deep in the case-interior and there is no intake duct for it, you are not likely to hear it as much.

So simply choosing a fan by its dBA rating may not reflect its true qualities. You want the highest CFM to dBA ratio that you can get, and there is no rule that you need to run a fan with high CFMs and 45 dBA at a speed that creates that noise. You may want to run the high CFM fan at half its top end, and the noise might well be in the 20's of dBA's.
 
Originally posted by: BonzaiDuck
There are some things to consider about dB ratings, assuming they are accurate. The noise consists of a combination of wind-turbulence and motor-noise, bearing noise or vibration. It is the motor-related noises which are most annoying, and the sound of "rushing air" is to be expected with high throughput, which improves cooling.

Then there is the issue -- assuming you choose fans with no motor-noise -- whether the fan is to be located at the front or the rear -- or even the top or the case. You are not likely to hear "wind-turbulence so much if it is at the back side of the case. If the fan is deep in the case-interior and there is no intake duct for it, you are not likely to hear it as much.

So simply choosing a fan by its dBA rating may not reflect its true qualities. You want the highest CFM to dBA ratio that you can get, and there is no rule that you need to run a fan with high CFMs and 45 dBA at a speed that creates that noise. You may want to run the high CFM fan at half its top end, and the noise might well be in the 20's of dBA's.
Click to expand...

This is very true. With recent help from BonzaiDuck I upgraded my 2 120 mm 36cfm@24dB fans to two more powerful models. One is an enermax that pushed 93 CFM at 35dB, the other is a panaflo that pushes 85 at the same dB. Using a fan controller I put them down to almost the lowest setting. This is even more quiet them the two original fans (though it seems to push the same amount of air). The largest noise I hear now is the wind out the back of my case.

On a side note, the enermax seems to push more air with less noise than the panaflo (M1A) even though the enermax is a 120x25 and the panaflo is 120x39. this is just based on a single nights operation but still seems interesting...

-spike
 
Originally posted by: Melectricus
Dear lord, 30db is what most people are trying to get rid of... and I don't mean the hairdryer crowd. I've replaced 26db fans people hate to the 19-21-ish range. 3db more means twice as loud, if you're looking for quiet, since some people have different definitions.
Click to expand...

10db more is twice as loud generally. 3 db is equivalent to 2 sources at the same time/db level.

To OP:
visit www.silentpcreview.com for silent pc tips. You will soon find out that your zalman psu is too noisy and opt for say a seasonic or nexus.

BTW, for most products, you cannot trust the db listed on the sticker.
 
Originally posted by: BonzaiDuck
There are some things to consider about dB ratings, assuming they are accurate. The noise consists of a combination of wind-turbulence and motor-noise, bearing noise or vibration. It is the motor-related noises which are most annoying, and the sound of "rushing air" is to be expected with high throughput, which improves cooling.

Then there is the issue -- assuming you choose fans with no motor-noise -- whether the fan is to be located at the front or the rear -- or even the top or the case. You are not likely to hear "wind-turbulence so much if it is at the back side of the case. If the fan is deep in the case-interior and there is no intake duct for it, you are not likely to hear it as much.

So simply choosing a fan by its dBA rating may not reflect its true qualities. You want the highest CFM to dBA ratio that you can get, and there is no rule that you need to run a fan with high CFMs and 45 dBA at a speed that creates that noise. You may want to run the high CFM fan at half its top end, and the noise might well be in the 20's of dBA's.
Click to expand...

Good point. The noise characteristic changes once you install the fan. Keep in mind all fans are tested in free air typically at 1m distance. this rating goes out the window once you mount the fan to you HS or case. Bearing and motor noise is also a big problem and typically doesn?t go away when you undervolt the fan.

When looking at queit fans I wouldn't buy anything rated over 22 dBA, Panaflows are for all practical purposes the best fans made.
 
Originally posted by: Tiamat
Originally posted by: Melectricus
Dear lord, 30db is what most people are trying to get rid of... and I don't mean the hairdryer crowd. I've replaced 26db fans people hate to the 19-21-ish range. 3db more means twice as loud, if you're looking for quiet, since some people have different definitions.
Click to expand...

10db more is twice as loud generally. 3 db is equivalent to 2 sources at the same time/db level.

To OP:
visit www.silentpcreview.com for silent pc tips. You will soon find out that your zalman psu is too noisy and opt for say a seasonic or nexus.

BTW, for most products, you cannot trust the db listed on the sticker.
Click to expand...

The problem with silentpcreview is that the are truly pasionate about having a silent PC with air cooling. They will dismiss fans that make even the slightest noise (to them, panaflo M1A's are out of the question, only L1A's are barely even acceptable at 5v). While it is a great resource for getting a super-quiet pc, I find them lacking in the quiet/good cooling category. For those who are power users, you do need a higher CFM setup then they normally reccomend.

Just a little warning...

-spike
 
This is the thing that frustrates me on the issue of "CNPS". Passive cooling solutions with heatsinks and even heatpipes do not work as well (or at all) without airflow. TEC cooling solutions do not work well without airflow and good case exhaust. Even with water-cooling, you still need fans for the radiator, whether external or internal.

My sister-in-law's Dell Pentium III 900 system is whisper-quiet. We built her a P-4 2.8C system in a midtower case, I confess this was one of my earlier "designs", and I visited periodically to replace smaller fans with bigger fans, and add ducting solutions. She has pointed out to me how the Dell is "whisper-quiet", but I have been "inside" the Dell, and by today's standards it is a sweat-box. The P-III systems could handle a higher case-interior ambient. So in addition to the CPU HSF, there were maybe two 80mm fans spinning at speeds that could not have been above 1,500 rpm.

My own system is still due for modification, with an option of replacing two 92mm fans with either one or two 120's. Or, I can leave the 92's, but I want to try a low-volume-high-airflow solution across my motherboard, and either re-orienting the 92mm exhaust fans or replacing with 120's will make the ducting design and construction easier.

Even so, I've got rid of almost all motor whine. Although I can tune up my intake and exhaust fans to higher speeds and CFMs where there is either some slight bearing rattle or slight motor whine, it does not improve cooling to any significant degree. The system is slightly noisier than the sister-in-law's Dell, but my load CPU temps never go over 40 or 41C at room temps between 70 and 73F.

Yet the noise-haters among various users may fail to grasp the practical trade-offs in the cooling-vs-noise issue, the fans-with-water issue, the TEC with HSF issue.

I'm not going to hate myself because someone in the noiseless-computer crowd has determined that my computer goes "shshshshshhhhh" and sounds like an air-conditioning vent with the AC fan on "Low" or even "Medium".
 
Sheesh, I didn't see my math error. 26db to 20db = 6db difference; which I approximated as twice as loud, which was the point I was trying to make. Thanks you are correct.

I'm not from the totally silent cut, but was only forwarning that 26 to 28db may be loud to some. Bearing noise can't be dismissed either. I have L1 and M1 in different cases and the M1's when connected to a fan controller are noticable on bearing noise, but that is me. The L1's are quiet and are a good choice.....$.02.
I don't have a silent computer, maybe next system.

Also a zalman fan bracket with a L1 goes a long way towards cooling passive heatsinks buried in a nice solid case.
 
There's more then decibels - low pitched noises are generally less iritating then high pitched ones, which is another reason to get the largest possible fans (120mm) and run them slow - you then just tend to get a low whoosh. Mount them so there's no hard contact to the case to transmit fan vibration and they will be much quieter as well (you can get rubber things to use instead of screws, or if you don't care about looks just tie the fan to the case with string, but put a knot between fan and case).
 
Originally posted by: Melectricus
Sheesh, I didn't see my math error. 26db to 20db = 6db difference; which I approximated as twice as loud, which was the point I was trying to make. Thanks you are correct.

I'm not from the totally silent cut, but was only forwarning that 26 to 28db may be loud to some. Bearing noise can't be dismissed either. I have L1 and M1 in different cases and the M1's when connected to a fan controller are noticable on bearing noise, but that is me. The L1's are quiet and are a good choice.....$.02.
I don't have a silent computer, maybe next system.

Also a zalman fan bracket with a L1 goes a long way towards cooling passive heatsinks buried in a nice solid case.
Click to expand...

My only issue with the L1's are their CFM. They don't push enough air for a hot summer day in my house. There is some noise with them other than the air movement, but for me, it is not really a big deal. This may be because I moved from a case with 5 80mm that were pretty loud to dual 120mm, so they seem REALLY quiet to me.

-spike
 
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