Panaflo Fan Confusion: FBA or FBL?

[koslov]

I've been snooping around for the optimal fans to use on my radiator, and as of right now, it's between the two versions of Panaflo's H1A: the FBA and the FBL. I run 80% Panaflo's in my case, so it's a brand I trust. I am planning to use a PWM controller with these fans, so high pressure and flow at high voltage and absolute silence at low voltage are requirements.

Here is the difference between these two models:

FBA:
Your standard axial box fan. Max air pressure of 6.18 mmH20 and airflow of 103.8 CFM.

FBL:
Octagonal layered "ringcage" housing. Supposed to reduce noise by as much as 5 dBa. Max air pressure of 5.5 mmH20 and airflow of 86.5 CFM.

Now here's where it gets confusing:

According to the spec sheet from Digikey, the max dBa of the FBL fan is 48, while the FBA fan is only 41.5. But the maxes occur at different points on the dBa / CFM graph. It's the fourth box down on the left side of the first page, titled "Panaflo-ES Noise vs Air Flow." So, at the highest static pressure, the FBL is noisiest, but at medium pressure, it is significantly quieter.

Now, according to Lytron, my rad will yield a mere .10 mmH20 air pressure drop at 70CFM. The FBL is supposedly louder at such small pressure drops like this. But why?

So, with all this data (and yet no actual "noise vs air flow" or "static pressure vs ariflow" comparing the 120mm versions), I am thoroughly confused on which one would actually be quieter in a real setup. Please help me out!

I would buy one of each and compare them, but unfortunately the FBL is $29, FBA is $18. However, if the FBL really yields 5 dBa less noise at the same airflow, $11 is certainly worth it for me.

edit: The FBL fan I am looking at is actually a U1A.

[Cyco-Dude]

erm....if it were me id just grab the cheaper / more powerful fan (ie, the first one you listed, or maybe a M1a instead of the h1a). you did say you were going to put it on a fan controller so sound shouldnt be an issue.

also, arent panaflos generally quiet fans? :shrug:

[UNDERBYTE]

You asked the right question.

I invented and Lic. the ringcage technology to panasonic.

the FBA is your choice as the panasonic design is louder at the lower statics towards free air due to harmonics with the stuts which dissapates against higher back pressures. I designed that out of the NMB fans so they are quieter by a couple of dBA than the fbl series. NMB only makes 60mm and 90MM, unfortunately.

Regards

[koslov]

Thank you Mr. Lemont, too bad about the harmonics of the Panasonic FBL. I tried looking at the NMB site, but it is down right now.

This technology has been around for 10 years now, hasn't it? Why haven't more manufacturer's licensed it from you? With most OEM PCs getting up in the 45 dBa range, seems like common sense to use a quieter fan design.

[UNDERBYTE]

t's niche to date has been mostly workstations, servers and telecom. Most people think the flat panel IMac uses no fan,it is that quiet, actually both Panasonic and Cheng Home both supply ringcage fans for The IMac.

How Much is a dBA worth?

Most manufacturers can not justify the added quarter in unit costs and NIH is a factor also. As thermal loads increase into the broader market I may see an increased adaptation of use.

I have designed an airfoil for the ringcage to reduce the broadband signature and have reduced noise from about 7 dBA on the NMB 92mm production modelto about -11dBA over the baseline original. Panasonic did their own design of the fan and is not as effective as the design I did for NMB. The new design varies less than a dB from 100% free flow to about 40% of free flow. This would simplify application as most tubeaxials will vary 4-8 dBA across the same range. watch for them from NMB, Panasonic has no interest to date.