Which Panaflo, H1A or L1A, should I use for my case?

[pioneerE99]

I have an Antec SX1040. I'm looking to replace the standard case fans included in the system. Current I have 3 fans that came with the case plus one 80mm Panaflo H1A for the case and another H1A for the CPU. I'm running an AMD 1700+ OC'd to 11*146 with an Alpha8045 and H1A fan, and a Leadtek Geforce3 TI200 clocked to 230/330, all running on an Abit KR7A. Should I get the quieter L1A fans or H1A fans to replace the 3 original fans? Will I have cooling issues by using the L1A's as case fans?

 

[SuperPickle]

If I were you. I'd put one H1A as the input, and 2 L1A'a as exhaust. You shouldn't have any airflow issues and, although you have some pretty hot parts, with all three fans running, you should have ample flow and the noise will be just a bit less. This configuration may also keep the pressure in your case more balanced. Sweet case BTW.

 

[PCHPlayer]

basilisk420, Why do you feel that pressure balance is necessary? A case will not implode if all fans are blowing out.
pioneerE99, Changing the case fans to H1A's will increase your air flow, but will increase the noise (Antec: 68 CFM @ 33 dBA, Panaflo: 79.2 CFM @ 35 dBA). The panaflo's will increase the noise by about 80%. If you change to L1A's you will decrease air flow, but dramatically decrease the noise (48 CFM @ 24 dBA). That's a 300% decrease in noise. You need to monitor the difference between the room temperature and the case temperature. A 1040 should be able to keep them within 3-5 C of each other. It's all a matter of balance between noise and heat. You need to decide your own tolerance for each.

 

[lsman]

i believe noise level double for every 10dbA.
So you % is wrong.

 

[pioneerE99]

What are some case and CPU temp I can refer to? Can you give me a range of what is tolerable?

 

[KouklatheCat]

You might think about getting the H1A's and putting them on a fan bus or rheostat. You can crank them up when you are playing games etc hardcore and leave them on a low speed when youre just typing a letter or surfing the web.

 

[PCHPlayer]

The dBA scale is a base 10 logarithmic scale (times 10). A logarithmic scale (such as the Richter scale) doubles every .3 (e.g. a 6.3 earthquake is twice as strong as a 6.0). Since the decibel (sp?) scale is times ten, it doubles every 3 decibels. Mathematically 10**.3 = ~2 and log10(5) + .3 == log10(10). These are rule of thumb numbers, not exact calculations.
This is why you cannot use CFM and dBA in equations to determine how noise efficient a fan is. The two scales don't match. I did some calculations myself and found the following efficiencies for Panaflo fans. These numbers make sense if you add 3 dBA every time you double the CFM.
L1A = 7.1 dBA / CFM (24 CFM @ 21 dBA)
M1A = 12.9 dBA / CFM (32.1 CFM @ 28 dBA)
H1A = 16.0 dBA / CFM (39.6 CFM @ 32 dBA)
Antec case fans 14.7 dBA / CFM (34 CMF @ 30 dBA)

As you can see the L1A gives you the best CFM for the noise and 2 M1A's would make an excellent replacement for the Antec fans (64.2 @ 31 dBA vs. 68 @ 33 dBA). They have similar CFM, but the Panaflo's are 60% quieter.
Isman, you are correct that the 80% number is wrong. It should be 60%.

 

[joecool]

pioneer, are you sure you aren't me?!

your setup is almost identical to mine, except that i've got the 1800+ oc'ed to 142, & my leadtek geforce3 ti200 oc'ed to 240/500(!). i wanted a quiet case so i went with the panaflo l1a's, an enermax adjustable fan on the 8045, & i replaced the anted psu with an enermax quiet psu. i put two l1a's on the front & two on the back. i am VERY pleased with both the sound (loudest fans are on the northbridge & vid card) and the airflow - it actually makes a faint "whooshing" noise. my cpu temps are 37C-42C idle-load. my case temps are higher than i would like but i think this is just because of the poor location of the thermistor - i suspect my actual case temps are very close to room temp.

so, bottom line, go l1a - with two in front & two in back you'll have more than enough air flow, plus low noise.

btw, pm me if you want - i bought 12 of the fans & now have a bunch i want to get rid of!

joe

 

[SuperPickle]

<< Since the decibel (sp?) scale is times ten, it doubles every 3 decibels. Mathematically 10**.3 = ~2 and log10(5) + .3 == log10(10). These are rule of thumb numbers, not exact calculations. >>



Your calculations are correct but while a 3dB increase is a double in sonic energy, it takes a 6dB increase in spl (sound pressure level) to be a perceived double in volume. An increase of 3dB is the minimum accepted increase to even tell the difference.



<< Why do you feel that pressure balance is necessary? A case will not implode if all fans are blowing out. >>



a negative pressure inside the case tends to draw air from any nooks and crannies possible...including drives. A positive pressure (more in than out) keeps most of the air flowing into the case exclusive to the designated spots (the intake fans) keeping the drives more free of dust--especially in a smoking environment. Also, the more balanced the pressure, the more efficient each fan is working.

 

[Maggotry]

I agree with basilisk, use + case pressure, not - case pressure. Relative to room pressure of course.

 

[Cosmo3]

I am using the stock Antec fans on the back of my 1040 case and L1A Panaflos on the front. I tried 2 92mm high speed fans on the front for intake fans and the 2 80mm L1As cool just as well without the noise. So the L1As will be fine for case fans without having to give anything up as far as cooling. I would use the H series fan on the cpu though, I am using a YS Tech 48 cfm fan on my 8045 heratsink and it is only 36 dba and does a good job. 1700+ XP overclocked to 1800+ and a cool 34C while surfing the net. Those readings are off of a Epox motherboard.