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Patent filings detail Retina MacBook Pro's quiet asymmetric fans

post #1 of 24
Thread Starter 
A trio of patent applications discovered on Thursday reveal how the asymmetric fan blade spacing used in the newest MacBook Pro with Retina display models quiet the spinning impeller without sacrificing performance.

Fan Patent
Source: USPTO


The three patent applications, all titled "Centrifugal blower with asymmetric blade spacing" and numbered sequentially by the U.S. Patent and Trademark Office (1, 2, 3) cover separate fan designs that feature asymmetrically aligned fan blades, two with 31 blades and one with 61 blades.

Apple first introduced its asymmetric fan design in June with the 15-inch MacBook Pro with Retina display and a subsequent teardown revealed that the laptop uses a 31-blade unit.

Typical fans incorporate a prime number of blades that are spaced at angles equidistant to each other, an industry standard aimed at reducing unwanted sound. At issue is the blade pass frequency (BPF) which produces harmonics from the pressure wave formed at the tip of each blade. The most noticeable source of noise is the pole pass frequency (PPF) tone, or the "vibration and resulting pressure waves created by the poles in the motor of the fan."

Graph
Source: Graph of sound pressure levels in a traditional fan versus on with asymmetric fan blades.


Apple's design calls for variably-angled blades that controls the spectral distribution of tones created by the fan. First-hand tests have found the new design to not necessarily quiet fan noise as much as create a less grating sound.

From the patent:

Dispersing the energy of a tone over a number of discrete frequencies can make the tone seem less noisy to the listener by reducing the perception on the tonal BPF [blade pass frequency]. Spacing fan blades unevenly, while maintaining impeller balance, is one method of controlling pure-tone effects.


According to the invention, the rearrangemnt of the fan blade angles cancels some of the noise usually heard in conventional portable computers but allows for the unit to still be balanced as the center of mass is located at the shaft of the impeller. The modified design also allows for the fan system to be smaller, thus permitting a thinner laptop as seen with the Retina MacBook Pros.
post #2 of 24
This is actually pretty good. It does help the noise massively. Pity about the rest of the notebook... Nah, just joshing. 1smoking.gif
post #3 of 24
Darn Apple and all these software patents.

/s
post #4 of 24
I think the article has to be missing something. Radiator fans have been asymmetric for a few decades, so that's not new by a long shot.
post #5 of 24
Quote:
Originally Posted by JeffDM View Post

I think the article has to be missing something. Radiator fans have been asymmetric for a few decades, so that's not new by a long shot.


Read the patents for more details.

Artificial intelligence is no match for natural stupidity.

"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."
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Artificial intelligence is no match for natural stupidity.

"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."
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post #6 of 24
Quote:
Originally Posted by Realistic View Post


Read the patents for more details.

That's kind of my point though, the article shouldn't be covering stuff that isn't unique or new and totally leave out the stuff that is. It's what I would call a wholly defective article.
Edited by JeffDM - 12/20/12 at 6:36am
post #7 of 24
Quote:
Originally Posted by JeffDM View Post


That's kind of my point though, the article shouldn't be covering stuff that isn't unique or new and totally leave out the stuff that is. It's what I would call a wholly defective article.

Looking at the first it seems to describe the exact design more than some of the others linked on here. The other descriptive elements are a bit more generic. They just mention improved thermal and acoustic performance. This is the list of claims on the first. I linked it to show that it's specific to the design .

 

Quote:
1. A centrifugal blower, comprising: a motor having a number of pole passes, wherein the number of pole passes is an even number; and thirty one impeller blades, wherein each of the thirty one impeller blades is associated with a nominal blade angle having a nominal blade angle value, the nominal blade angle being an angular displacement between adjacent impeller blades, wherein the number of impeller blades are each spaced asymmetrically about a central hub such that each impeller blade position about the central hub such that a summation of the nominal blade angle values is equal to 360.degree. and an operating characteristic value of the centrifugal blower is deemed to be within a pre-determined range of operating characteristic values, wherein a first nominal blade angle value is 10.1034.degree., a second nominal blade angle value is 10.0229.degree.; a third nominal blade angle value is 13.1577.degree.; a fourth nominal blade angle value is13.2029.degree.; a fifth nominal blade angle value is 13.6692.degree.; a sixth nominal blade angle value is 13.0442.degree.; a seventh nominal blade angle value is 13.5653.degree.; an eighth nominal blade angle value is 11.9834.degree.; a ninth nominal blade angle value is 11.6129.degree.; a tenth nominal blade angle value is 10.1071.degree.; an eleventh nominal blade angle value is 11.2424.degree.; a twelfth nominal blade angle value is 10.1532.degree.; a thirteenth nominal blade angle value is10.1816.degree.; a fourteenth nominal blade angle value is 9.7922.degree.; a fifteenth nominal blade angle value is 13.4336.degree.; a sixteenth nominal blade angle value is 13.6681.degree.; a seventeenth nominal blade angle value is 12.6063.degree.; an eighteenth nominal blade angle value is 9.5578.degree.; a nineteenth nominal blade angle value is 10.0681.degree.; a twentieth nominal blade angle value is 10.7533.degree.; a twenty-first nominal blade angle value is 11.1850.degree.; a twenty-second nominal blade angle value is 13.5670.degree.; a twenty-third nominal blade angle value is 12.4725.degree.; a twenty-fourth nominal blade angle value is 13.1224.degree.; a twenty-fifth nominal blade angle value is 13.0726.degree.; a twenty-sixth nominal blade angle value is 13.1187.degree.; a twenty-seventh nominal blade angle value is 12.0408.degree.; a twenty-eighth nominal blade angle value is 10.6195.degree.; a twenty-ninth nominal blade angle value is 9.5566.degree.; a thirtieth nominal blade angle value is 9.6588.degree.; and a thirty-first nominal blade angle value is 9.6605.degree..

2. The centrifugal blower as recited in claim 1, wherein each of the nominal blade angle values has a tolerance range of +/-5%.
post #8 of 24

Why does the article say "without reducing performance???".

 

It's been well documented that the GPU in the rMBP is quite heavily throttled (made worse by a "software update" that was eventually pulled by apple) specifically because the machine doesn't have adequate cooling to run it wide open. The computer gets too hot because the fans and case are not properly designed to allow the computer to operate without reducing the performance of the components via software throttling.

 

So "without reducing performance" is totally false; the design of these fans requires reducing performance.

post #9 of 24
I can't attest to all the MacBooks between a PowerBook G4 and the latest MacBooks. However, My new MacBook Pro is pretty much silent; My old G4, not so much.
post #10 of 24

Apple should be moving away from rotating fans anyway. Ancient technology. I like GE's dual piezo cooling jet. Less noise, smaller size, higher reliability, lower power consumption.

post #11 of 24
Quote:
Originally Posted by Kolchak View Post

Apple should be moving away from rotating fans anyway. Ancient technology. I like GE's dual piezo cooling jet. Less noise, smaller size, higher reliability, lower power consumption.

I'm impressed if they really can make piezo more efficient than a fan. I don't think that was true before.
post #12 of 24
Originally Posted by Superbass View Post

So "without reducing performance" is totally false; the design of these fans requires reducing performance.

 

I believe "performance" refers to the cooling efficiency of the fans, not the efficiency of the CPU.  The asymmetric fan blade design reduces the perceived noise (but not the actual sound level) without reducing the volume of air that the fan can move over the components that need cooling.

 

Eurocopter has a vaguely similar patent on their distinctive "Fenestron" tail fan on some of their helicopters.  It's ducted, it has asymmetric blades, and it's smaller and spins at a higher speed than a conventional open tail rotor would.  The asymmetry spreads the noise out over a wider frequency range, reducing its audibility.  (And the surrounding "duct" improves safety for pedestrians while the helicopters are on the ground, etc.)

Sent from my iPhone Simulator

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Sent from my iPhone Simulator

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post #13 of 24
Quote:
Originally Posted by malax View Post

Darn Apple and all these software patents.
/s

First the rounded rectangle, now Apple thinks they can patent fan blades now?

/s

"Apple should pull the plug on the iPhone."

John C. Dvorak, 2007
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"Apple should pull the plug on the iPhone."

John C. Dvorak, 2007
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post #14 of 24
Originally Posted by Suddenly Newton View Post
First the rounded rectangle…

 

You know, some people still say that seriously. Disturbing.

Originally Posted by asdasd

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Originally Posted by asdasd

This is Appleinsider. It's all there for you but we can't do it for you.
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post #15 of 24
Quote:
Originally Posted by Tallest Skil View Post

You know, some people still say that seriously. Disturbing.

I mentally substitute it with "Yes, I'm really dumb enough to say this".
post #16 of 24
Originally Posted by JeffDM View Post
I mentally substitute it with "Yes, I'm really dumb enough to say this".

 

Hey, maybe we could actually edit the Huddler text replacement. This opens a ton of doors…

 

"Ha! Apple Yes, I'm really dumb enough to say this*, their I'm a complete moron†, and I drank a soda carbonated with hydrogen cyanide as an infantª."

 

*patents rounded rectangles

†products sell because of marketing only

ªSteve Jobs would never have run it this way

Originally Posted by asdasd

This is Appleinsider. It's all there for you but we can't do it for you.
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Originally Posted by asdasd

This is Appleinsider. It's all there for you but we can't do it for you.
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post #17 of 24

Well I have to say it works.  I have the 15 Pro Retina and it is brilliant in form and function.  I play allot of games and the noise is present but with little distraction.  Whatever they are doing is working.
 

post #18 of 24
Quote:
Originally Posted by JeffDM View Post

I think the article has to be missing something. Radiator fans have been asymmetric for a few decades, so that's not new by a long shot.

The actions achieved by the two, however, are fundamentally different.  Radiator designs have more to do with maintenance loops and Apple's design has more to do with noise and profile both items that are specified in this article.

 

NOTE: Because the design goals of the two are very different, the designs are not, in any way, interchangeable and are very different.

post #19 of 24
Quote:
Originally Posted by Steven N. View Post

The actions achieved by the two, however, are fundamentally different.  Radiator designs have more to do with maintenance loops and Apple's design has more to do with noise and profile both items that are specified in this article.

NOTE: Because the design goals of the two are very different, the designs are not, in any way, interchangeable and are very different.

What do you mean by maintenance loops?
post #20 of 24

Why is SPL on the graph A-weighted? At that frequency range the weighting wouldn't really effect much....

post #21 of 24
Quote:
Originally Posted by Superbass View Post

Why does the article say "without reducing performance???".

It's been well documented that the GPU in the rMBP is quite heavily throttled (made worse by a "software update" that was eventually pulled by apple) specifically because the machine doesn't have adequate cooling to run it wide open. The computer gets too hot because the fans and case are not properly designed to allow the computer to operate without reducing the performance of the components via software throttling.

So "without reducing performance" is totally false; the design of these fans requires reducing performance.

No. Apple is perfect. Seriously though, I wonder what the details are on the throttling of the rMBP 13" and 15". Please elaborate.
post #22 of 24
post #23 of 24
Quote:
Originally Posted by z3r0 View Post

I wonder if the Sandia CPU cooler took design cues from Apple's fan:
http://www.geek.com/articles/chips/sandias-floating-spinning-heatsink-promises-30x-better-cpu-cooling-20120625/

It is interesting in its own right. The only thing that appears similar is a flat centrifugal fan type, and that's not new idea. It appears to only have one blade angle interval, rather than an asymmetrical blade pitch. Apple's patent is about a very specific pattern of blade spacings, just the article either doesn't say that or says it poorly.
Edited by JeffDM - 12/22/12 at 8:40am
post #24 of 24
Quote:
Originally Posted by Superbass View Post

Why does the article say "without reducing performance???".

It's been well documented that the GPU in the rMBP is quite heavily throttled (made worse by a "software update" that was eventually pulled by apple) specifically because the machine doesn't have adequate cooling to run it wide open. The computer gets too hot because the fans and case are not properly designed to allow the computer to operate without reducing the performance of the components via software throttling.

So "without reducing performance" is totally false; the design of these fans requires reducing performance.

It's not likely the fan design that requires dropping the performance. Dynamic clocking is a standard feature in both CPUs and GPUs.

The following links suggest it's that Apple is just underclocking sooner than necessary so it shouldn't be anything to do with the design:

http://appleinsider.com/articles/12/11/13/some-15-retina-macbook-pro-users-complain-of-graphics-issues-after-efi-update
http://forums.macrumors.com/showthread.php?t=1432352

The temperatures being reported are fine and the issue doesn't seem to affect everyone the same.

One thing for sure is that the fan design seems to have taken away the higher pitched noise you can hear on the 2011 model:



and just leaves a sound of rushing air, which is much more tolerable:

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