wow!! - 52 cfm @ 18dBA (but there's a catch)

jhh · Post by **jhh** » Thu Feb 06, 2003 5:19 pm

..well there had to be didn't there! These fans are HUGE - 172mm across - just less than standard case width, so you could in theory have one of these as a chimney fan.

see fan on 2nd page at lowest manual settings http://www.papst.de/pdf_dat_e/S32gb.pdf

Maybe not so practical as they need 24v, but for someone who wants speed AND quiet this is by far the highest performance silent setup I've ever seen. If there's anyone here crazy enough to put one of these in their pc I'd love to hear how it goes!

Maybe you could undervolt the 12v version to get similar figures, but it'd prob need a capacitor to kick in.

seishino · Post by **seishino** » Thu Feb 06, 2003 7:36 pm

I'm a little hesitant about the whole temperature-control thing. I'd probably find out what kind of resistance the temp sensor puts up at minimum, replace it with a variable resistor, and undervolt it.

If it starts up at 8, you still get plenty of airflow but with much less noise. Sound like the sort of thing you would put inside the case to make a chimney between a graphics card, CPU, and PSU. I'll keep an eye open for them, thanks for the link!

Justin_R · Post by **Justin_R** » Thu Feb 06, 2003 8:53 pm

jhh-

I think you may have read their chart wrong. The only place I see an "18" is in the power input for one of the fans. The dB(A) readings are mostly in the 50s (although the variofan model gets down to 35).

Am I missing something?

Post by **MikeC** » Thu Feb 06, 2003 9:20 pm

no, the fan on the second page IS rated from 18 to 65 dBA-- and 53 to 353 cfm. It is a 48V fan, no indication of what is the min voltage at which this 18 dBA is attained. It does sound amazing; I'd have my doubts simple because of the moving mass of the fan. I think it would make some low freq noise unavoidably. But someone try it! Or check and see whether it is a typo.

Justin_R · Post by **Justin_R** » Thu Feb 06, 2003 10:40 pm

You're right.

It lists the fan's nominal low speed at 800 RPM, which I imagine would cut down substantially on mechanical noise from the motor/bearing mechanisms.

Incidentally, since we know the voltage and wattage at the maximum speed, we could determine the current and resistance of the fan circuit at that voltage, no? Could we then use that same current and resistance with the low-speed wattage to determine what voltage is used for the low speed? I'm not sure if doing that would be theoretically correct, let alone correct for practical purposes, but I thought I'd ask. (You'd get something like 2V, I believe, which seems unlikely to be right.)

Anyway, the second page also says that a 24V version is in the works, so if the 48V doesn't operate at a PC-friendly voltage, the 24V might.

jhh · Post by **jhh** » Fri Feb 07, 2003 6:29 am

I'm only testing the ground here, but Mike, this might be just the thing for the silent and high end system you're making for that games expo thing. This thing pushes more than delta and is quieter than panaflo! I couldn't think of a better way to convert all hose overclockers to silent!

I think it'd be all low freq noise, which is typically harder to dampen and less likely to be significently represented on the dBA scale (due to that we hear low noises least) but I've always thought the low-pitched noises were the most bearable anyway. 800 rpm would produce a VERY low sound, maybe on the edge of/below of the human audiable range?

I'm a little hesitant about the whole temperature-control thing

there are two temerature controled models, and two manually controled ones we'd want teh manual ones. I'd bet that the circuiritry in this fan is smart enough to start at higher voltage to kick the fan in and then drop down to a manually selected level.

My case (which is an Estar entry-level server, sinilar to chieftec in many ways) could comfortably fit one of these between PSU and CD drives, and then there's room for one at the front intake too (there's a 3cm gap between front bezel and chasis and then another 3cm to the drive cages so users can stack fans) Withthat kind of airflow I think passive cooling of a good athlon may be possible.

jhh · Post by **jhh** » Fri Feb 07, 2003 8:04 am

fyi: I've mailed papst re: voltages etc. I'll post here when/if I get a reply.

Post by **MikeC** » Fri Feb 07, 2003 9:06 am

This thing pushes more than delta and is quieter than panaflo! I couldn't think of a better way to convert all hose overclockers to silent!

I think it'd be all low freq noise, which is typically harder to dampen and less likely to be significently represented on the dBA scale (due to that we hear low noises least) but I've always thought the low-pitched noises were the most bearable anyway. 800 rpm would produce a VERY low sound, maybe on the edge of/below of the human audiable range?

Have to dispute you on that -- a Panaflo at 7V or less is inaudible at more than say 12-18" away -- depending on your hearing and ambient. I KNOW it's ~10 dBA or less even though there is no way to measure it. I have a couple of so-called "12 dBA" Papst 80mm that are about the same loudness as the Panaflo (both at 12V) but click audibly at slower speeds, so I have my reservations about Papst noise claims.

There is also the simple issue of airflow noise: no way you can move air at 53 cfm through a PC case without the airflow making noise. Even if the fan blades were so cleverly designed that they didn't produce any turbulence, this level of airflow would cause whistling and turbulence in the case as it flowed around the various impedances in it.

But it would still be real interesting to see what could be done with it if that 18 dBA figure is for real.

jhh · Post by **jhh** » Fri Feb 07, 2003 9:52 am

ok, I admit that "quieter than a panflo" was a a bit of a simplistic thing to say. I was making a more general point about the incredable figures than anythig that would stand upto close inspection.

the hole the air travels through is four times that of an 80mm fan without it pushing four times as much air, so noise due to turbulance at high airflow would be a lot quieter than expected. This would certainbly be the case in free air, where the fan was most likely measured. In a pc I think one of these might not play too badly as an exhaust provided there are ample holes for intake towards teh bottom of the case.

The air would only have to move as quickly as it would for a 80mm fan pushing 13.25 cfm.

I've decieded that if I can find a uk/european seller to do these at a resonable price then I'm going to go for it! I've even managed to find a 172mm grill so the metal blades won't chop my fingers off!

Of course Mike, if you can use your SPCR powers to get a free sample I won't argue (I used to write for a pc mag, y'know!)

andrew · Post by **andrew** » Sun Mar 16, 2003 8:40 pm

So, how did it turn out?

Is the fan silent and does it push as much air as it claims? (This sounds altogether too good to be true.)

Katana Man · Post by **Katana Man** » Sun Mar 16, 2003 9:01 pm

Heck, I'll try it. Anyone know where I can get one in the USA?

Bat · Post by **Bat** » Mon Mar 17, 2003 11:45 am

Another point to bear in mind is that those flow-rate values are in free air with no obstructions. I'm sure that a big fan like that would provide much less pressure at a given flow rate than a smaller fan, or to put it another way, for a given back-pressure there would be less flow.

andrew · Post by **andrew** » Thu Apr 03, 2003 2:35 pm

any update?

fmah · Post by **fmah** » Thu Apr 03, 2003 7:19 pm

I have the Comair Rotron 172mm fan. I've run the 24V version at 12V, it moves a lot of air, but is not silent. It's reasonably quiet but the ones I have have some slight high pitch sound. I'm going to try putting in a resistor to slow it down even more to determine what minimum speed and sound relation there is.

andrew · Post by **andrew** » Thu Apr 03, 2003 9:16 pm

Is there a lot of the high-pitchedness?

Would running two of these instead of four panaflos provide a low enough increase in noise to compensate for the EXTREME increase in airflow?

fmah · Post by **fmah** » Thu Apr 03, 2003 9:21 pm

It seemed to come and go, which could be because these are old units, unused but manufactured a few years ago. The single one at 12V seemed louder than the 4 NMB 120mm I have at 5V. However, it was moving more air. I will need to try reducing the speed, and I was planning on a 2 x 172mm bracket in the future.

Update. Looks like some of the other ones I have are quieter, but it also seems I need to gasket the fan in the mounting bracket. Anway, I also tried the Vantec fan controller on these since the controller goes from 7-12V. Before I can turn the control down to midway, the fan stops, so it seems the low end is around 10V for these fans. However, going from 12V to 10V doesn't seem to change much. The Vantec is noisy if any channel is half or less anyway. I will reinstall one of the other fans with gaskets and listen to it.

wow!! - 52 cfm @ 18dBA (but there's a catch)

wow!! - 52 cfm @ 18dBA (but there's a catch)

Temperature controlled...

Pressure