SOLO whooshing noise

Enclosures and acoustic damping to help quiet them.

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speedkar9
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SOLO whooshing noise

Post by speedkar9 » Sat Dec 27, 2008 4:21 pm

I've just finished an (all stock) Solo build. I've got it setup with a tower cooler, 120mm PSU, and 120mm exhaust fan as a negative air pressure system.

When I run it, I notice that (with the rear PCI vent taped) there is an immediate whooshing noise upon closing the side of the case, and a reduction of air exiting the rear fan. Removing the tape lessens the whoosh, but it is still apparent, and I can feel air entering the vent from the back.

What solutions are there to curing the whooshing noise? It is the most predominant noise in my computer (and was in my P180 and 300), and I'd like to get rid of it. Two suggestions I've come up with is:
1) Cut the fan grill. I really don't want to mod this case, but does it make that much of a difference in the whoosh?
2) Remove the steel plates that cover the CD bays, remove the 3.5-5.25 converter, as well as the front fan holder. This could remove potential air obstructions and allow more air to enter the surrounding vents around the 5.25 bays. (Dust isn't an issue) But will this allow sound to escape?

Suggestions?

Specs: AMD 5600 X2 89W, 2GB Kingston, WD5000AAKS, Asus M3A78-EM, Asus 8600GT 512MB Silent, Pioneer DVR-216, Seasonic S12II 380, Antec Solo, AC Freezer 64, AC 12 PWM exhaust fan.
Last edited by speedkar9 on Mon Dec 29, 2008 6:30 pm, edited 1 time in total.

danielG
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Post by danielG » Sat Dec 27, 2008 5:49 pm

How fast is your exhaust fan running?

I have a 1200 rpm Slipstream at the rear exhaust of my P182. At 1200 rpm it makes a whooshy sound. I guess it might be the grill. But I'm running it at 800 rpm and it doesn't whoosh. Never had to raise the fan speed yet.

Depends on the fan too. My 800 rpm S-Flexes (top, middle) make a "whooshier" sound that the Slipstream running at the same speed.

porkchop
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Post by porkchop » Sat Dec 27, 2008 6:49 pm

from your comments on fan speeds i will assume slowing them down isn't an option :)

i think you're on the right track with reducing the amount of obstructions, rather than cutting the grill though- i would consider removing any pci slot covers you may be using. removing the front intake filters- or the whole fan assembly is also a good idea.
i'm not too sure what the fan bracket does for sound, i can't imagine it doing a whole lot.

be aware though that more air in from the back means less in from the front, resulting in reduced cooling for any hdds you have in the hdd cage.

speedkar9
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Post by speedkar9 » Sat Dec 27, 2008 6:52 pm

danielG wrote:How fast is your exhaust fan running?
Right now the exhaust is running at 964 RPM (PWM) and the AC Freezer 64 I've undervolted with a resistor and it runs at 1400RPM. A quick check shows that some whining is coming from the Freezer, although I the whooshing is probably coming from the negative air pressure in the case trying to get air (only happens when I close the case).

HW monitor:
CPU: 34C
Mobo: 39C
Core 0: 34C
Core 1: 31C
GPU: 52C

NeilBlanchard
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Post by NeilBlanchard » Sat Dec 27, 2008 7:46 pm

Hi,

You could remove the front filter, and see if that helps reduce the noise a bit?

danielG
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Post by danielG » Sun Dec 28, 2008 4:43 am

speedkar9 wrote:Right now the exhaust is running at 964 RPM (PWM) (...)
As far as I can tell, that's too fast. I have a AC AF12025 PWM on my CPU heatsink. At idle, it runs at 550 rpm, therefore, it doesn't bother me. However, over 900 rpm that fan starts to get noticeable.

Try running that fan at 800 rpm or under, if you can, and see what happens.


EDIT: I thought I had the same fan as you, but I don't. Yours is 38,5 mm deep. Corrected the post, but I now realize my experience does not relate to yours. :(

speedkar9
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Post by speedkar9 » Sun Dec 28, 2008 8:23 am

NeilBlanchard wrote:Hi,

You could remove the front filter, and see if that helps reduce the noise a bit?
I never installed the filter in the first place. I was wondering if removing the metal covering the 5.25 drives, as well as the fan holder in the front would allow more air to enter? But is that going to let more sound out? Any other SOLO users have a whooshing problem with the side panels closed?
Thanks

hybrid2d4x4
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Post by hybrid2d4x4 » Sat Jan 03, 2009 9:15 pm

If it's a whoosh sound that I'm thinking of, then its just a byproduct of high airflow due to high fan RPMs. I don't know how your ambient noise level is, but in my case, I start to hear the whooshing sound in my HTPC if the 120mm fans run above 700RPM or if the 80mm in the PSU gets above 1100 RPM.

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Post by MikeC » Sat Jan 03, 2009 10:20 pm

hybrid2d4x4 wrote:If it's a whoosh sound that I'm thinking of, then its just a byproduct of high airflow due to high fan RPMs. I don't know how your ambient noise level is, but in my case, I start to hear the whooshing sound in my HTPC if the 120mm fans run above 700RPM or if the 80mm in the PSU gets above 1100 RPM.
Agreed. I built 4-6 systems in the solo/p150 -- never this issue. But the exhaust fan probably never runs higher than ~800rpm. Doesn't need to.

speedkar9
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Post by speedkar9 » Sun Jan 04, 2009 7:04 pm

MikeC wrote:Agreed. I built 4-6 systems in the solo/p150 -- never this issue. But the exhaust fan probably never runs higher than ~800rpm. Doesn't need to.
Are there any easy and cheap ways to make PWM fans run slower than their rated minimum speed? Right now I'm using a resistor to under volt the exhaust fan (AC 12 PWM) and it runs at ~900RPM, while the AC Freezer 64 is allowed to ramp up under load (idles at ~1100 RPM).

speedkar9
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Post by speedkar9 » Sat Jan 10, 2009 5:57 pm

An update: I've added some resistors to under-volt the fans:
Freezer 64: ~900 RPM
Rear 120mm: ~700RPM

The reduced airflow in the case (due to the case fan) had a noticeable increase on video card temperatures (+8C), and the whooshing noise is somewhat reduced. However, the power supply fan (I've found it the loudest component in my system, yet its SPCR recommended, an S12II 380) now ramps up especially under load, and also contributes to a whooshing sound, noticed mostly from the back of the computer.

Is the S12II really supposed to be that "loud" (in my terms, by far not defectively loud)? I've noticed its got some clicking noise to it.

dhanson865
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Post by dhanson865 » Sun Jan 11, 2009 7:38 am

Do you have a power meter (killawatt, power angel, clamp meter)? Can you tell us the AC loads you are seeing?

Another question how warm is it in the room where the PC is?

The S12 isn't perfect but assuming the power draw is low and the room temp is low it shouldn't be a nightmare.

I have a Solo/S12 setup and I'm happy with it but then again the fans I'm using are

exhaust: Yate Loon 1300 RPM (I tried running it at 5v and it wouldn't start reliably so I moved it up to 7v, then for kicks I tried it at 12v) doesn't bother me at any of the 3 voltages.

intakes: Scythe 92mm Case Fan x2 - DFS922512L 2000RPM which both got put on 5v the first day and have run that way ever since.

I got all those fans under $5 a piece and have no complaints about them or the Solo they are in (other than the power/reset button being so cheap).

oh and I am using the filter.

speedkar9
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Post by speedkar9 » Sun Jan 11, 2009 10:20 am

dhanson865 wrote:Do you have a power meter (killawatt, power angel, clamp meter)? Can you tell us the AC loads you are seeing?
No I don't have a power meter. I'd assume that my 89W 5600+ x2 chip, 780G chipset, and an 8600GT card wouldn't cause the PSU fan to ramp up. Besides, it never ramped up before when the fans were turning faster.
dhanson865 wrote:Another question how warm is it in the room where the PC is?The S12 isn't perfect but assuming the power draw is low and the room temp is low it shouldn't be a nightmare.
~20-22C. Motherboard temperature (not sure where the sensor is) shows ~40C (it was 33C when I had the AMD stock cooler, so I'm thinking the sensor is around the CPU area). Are there people who have had to swap fans on these? I think the PSU also contributes to a "hushing" or whooshing sound, along with a slight repetitive clicking noticeable up close.
dhanson865 wrote:intakes: Scythe 92mm Case Fan x2 - DFS922512L 2000RPM which both got put on 5v the first day and have run that way ever since.I got all those fans under $5 a piece and have no complaints about them or the Solo they are in (other than the power/reset button being so cheap).
Why do you need intakes? I never planned on using intakes on mine, and am infact surprised that my temperatures are that low. With the 120mm exhaust, and 120mm PSU fan, after 2 weeks I noticed a thin line of dust building up on the front bezel vent, signifying that the negative air pressure setup is working.
dhanson865 wrote:oh and I am using the filter.
I've completely removed the metal CD drive covers, the 5.25 to 3.5" converter, the front fan holder and filter to allow more air to enter from the front. Dust doesn't bother me too much.

vertigo
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Post by vertigo » Fri Jan 16, 2009 6:58 am

Speedkar9, stop hot air getting to the PSU and it won't ramp up. (Use a partition perhaps)

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