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 Post subject: Re: Slight error
PostPosted: Wed Jul 22, 2009 12:14 pm 
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Joined: Tue Mar 17, 2009 10:26 am
Posts: 177
Location: Germany
Cistron wrote:
Speaking about units, I think the commata aren't in the right position for the size specifications in inches.
Quote:
130 x 100 x 158 mm
51.2 x 39.4 x 62.2 inch

Now, if only I could do some 3D-rendering...
A 1.5m x 1m x 2m heatsink, with let's say 100 fins which would be about 7 micrometers thick each...
Code:
---------------------------------
|                               |
|                               |
|                               |
|                               |
|                               |    <- heatsink
|                               |
|                               |
|                               |
---------------------------------
               .                     <- processor

Those fins might be prone to bending/breaking, though :)
(Yes, I'll stop now)


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 Post subject:
PostPosted: Thu Jul 23, 2009 8:29 am 
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Joined: Wed Oct 22, 2008 8:49 am
Posts: 454
Location: Where I Am
K.Murx wrote:
A 1.5m x 1m x 2m heatsink
Does it come with a fan or do I have to purchase one separately?
K.Murx wrote:
(Yes, I'll stop now)
So you should. :)


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 Post subject: Difference between SY1225SL12LM-P and SY1225SL12M
PostPosted: Sat Jul 17, 2010 9:57 am 
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Joined: Sat Jul 17, 2010 9:49 am
Posts: 1
Location: Iceland
I was wondering about the difference between the SY1225SL12M and SY1225SL12LM-P. Is the latter identical to the former with the addition of PWM control? Thank you for an excellent article.


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 Post subject: Re: Difference between SY1225SL12LM-P and SY1225SL12M
PostPosted: Sat Jul 17, 2010 12:28 pm 
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Joined: Fri Aug 05, 2005 3:29 am
Posts: 1220
Location: UK
I am aware that the review states that the SY1225SL12LM-P has a top speed of 1200 rpm, but this is not the case. It actually has a top speed of 1300 rpm (as you can see the SPCR sample ran at 1340 rpm). The article correctly states that the airflow rating of the PWM fan is 74.25 cfm. The spec for the SY1225SL12M is 68.54 cfm which bears out the difference in top speeds.


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 Post subject: Re:
PostPosted: Wed May 04, 2011 4:59 am 
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Joined: Tue Nov 04, 2008 6:03 am
Posts: 367
Location: Sweden
I'm arriving a little late at the party, I guess...

I suppose an extrapolated conclusion (as drawn by me as well as several other readers) is that a very good budget solution is to add asecond fan of the original variety...

PartEleven wrote:
Does scythe sell that PWM slip stream fan separately?
Yes! (And you also need an extra set of clips, type "A".)

MikeC wrote:
OK, to clarify the 2 fans vs 1 fan SPL measurements and perceived noise, I ran some extended tests ... All the tests were conducted in the anechoic chamber, whose ambient was reading ~11 dBA. ...

either fan at 1000 rpm: 14 dBA/1m
both fans at 1000 rpm: 18 dBA/1m
This makes sense, more or less. ...

either fan at 700 rpm: 11 dBA/1m -- 12 dBA/0.5m
both fans at 700 rpm: 12 dBA/1m -- 14 dBA/0.5m
The first reading above -- 11 dBA/1m for the single fan at 700rpm (which is roughly the same speed as 7V w/ the Nexus 120) -- is suspect. Why? It's the ambient level. This means the fan could be anywhere between 0 and 11 dBA/1m and there's no way to tell, because 11 dBA is the lowest we can measure.
I think there's a difference between what can be measured and what can be calculated.
I know from the screenshots that your equipment provide two decimals to the measured value, which adds quite a bit of precision.

To get a more accurate value of the fan noise it's just a matter of subtracting the background noise:
(Actual fan noise) = 10 x log( 10^(Measured fan noise)/10 - 10^(Measured background noise)/10 )

Example 1, both fans at 1000rpm.
Measured: 18.00 dB
Background: 11.00 dB.
Actual fan noise: 10 x log(10^1.8-10^1.1) = 10 x log(63.10-12.59) = 10 x 1.70 = 17.0 [dB]

Example 2, both fans at 700rpm (1m distance).
Measured: 12.00 dB
Background: 11.00 dB.
Actual fan noise: 10 x log(10^1.2-10^1.1) = 10 x log(15.85-12.59) = 10 x 0.51 = 5.1 [dB]

On top of these result one can then add the inaccuracy of the audiometer.

Cheers
Olle


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