Yet another quest for silence

lm · Post by lm » Wed Dec 17, 2003 9:03 am

Found this site recently, and found lots of useful information. This is my first post here, just to introduce myself.

So here's my setup:

Server machine (on 24/7, running debian linux, on UPS)

case Aopen HQ08 with the PSU that came with it
intel P3 733MHz slot 1
intel cc820 mobo (integrated sound)
2 * 256 sdram, i think it's 133MHz
Seagate Barracuda IV 80GB
Matrox Millennium 1, 4MB
2* Intel 100Mbps nic

Measured that the system draws 42w AC @ idle, <60w AC at full load

Used for NAT, mail, http server, ftp server, irc and web browsing terminal,
maybe even watching movies some times.

Mods done:
- psu fan swap: PAPST 8412NGL @ 12V
- psu fan grill cut away
- self made 80mm cpu fan holder attached to case
- cpu fan PAPST 8412N/2GL @ 12V
- front intake grill cut away
- cut & drilled additional front intake, 80mm
- 2 front intake fans PAPST 8412NGL @ 5V, with air filters
- front,sides,top and bottom of case covered with 30mm heavy sound damping material (20mm where the 30mm does not fit). Self-cut pieces for maximum coverage of everything.

To do:
- barracuda is just screwed normally on top of psu, suspend it (heat?)
- remove sound damping material, silence should be possible without.
- undervolt cpu and psu fans to 7V or 5V (could i connect them in series for 6V? they are same model)
- all fans screwed in atm, replace screws with soft rubber thingies
- what else do i need?

Currently: Quiet, all noise is low frequency
Target: Inaudible from where i sit (computer under the table)

Desktop machine (on during daytime, running windows, on UPS)

case Antec Sonata Piano with the PSU that came with it
AMD athlon XP barton 2800+ (clocked 2GHz, FSB 400)
Asus A7N8x Deluxe 2.0
2 * 512MB DDR 400MHz
Zalman 7000A-AlCu with AS5
Matrox g550
Seagate 7200.7 SATA 80GB
Logitech MX500
MS natural kbd
2 * Samsung Syncmaster 959nf

Havent modded this one yet, not quiet but only low-freq noise and definitely not loud.
Target is to be as quiet as it can, but doesn't need to be silent from where i sit (computer under the table).

Zalman fanmate for cpu fan is at min speed, and case fan connected to the fan-only output of the psu.

This system draws 117w AC @ idle, and 151w AC with cpu burn

To do:
- buy PAPST 4412F/2GL to replace case fan
- cut away case fan grill
- buy Seasonic Super Tornado or silencer (cant really get them from Finland)
- try to improve intake airflow somehow
- cut one of the L11 bridges on barton for changing voltage id
- undervolt as much as possible after cutting the L11
- maybe even underclock as i don't really need all that speed
- anything else that comes to mind?

Some general thoughts...

If antec has efficiency of 65% at my load and seasonic has 75%, then i would go from 117/151w AC down to 100/130w AC.
That would mean 20w less heat and thus less need for fan speed.
Also undervolting would potentially give big gains in reduced heat, but i lose my guarantee when cutting L11 bridge.
Combined, and if i manage to improve intake airflow, these would mean much less need for fan speed.

About those samsungs: they have high-pitched noise when computer is off but they are on.
Of course that situation does not happen so it does not matter. Also, when they enter
power save mode, and slowly blink their power led, i can hear a very high frequency noise,
and the frequency changes when the led blinks on/off, so from the sound i know when the led is on or off.
This is very hard to hear, but if it's otherwise silent, and i am reading, i can hear it from the other side of the room after a while.
When they are on and the computer is on, i dont hear any noise from them.

My keyboard is not silent, and my mouse buttons are not either. They are very annoying when i try to use my computer at night
when my gf is sleeping. The computers are both in our bedroom.

The hq08 case is a pain to open. Needs a screwdriver and 5 screws at min to get one side open. And the side slides to
back, so there needs to be one case-lenght of space behind it! Also connecting sound damping material to sides is not possible, nor
making a duct to the side from the cpu fan. Otherwise good case.

The sonata seems to have very bad intake airflow. MBM5 measures these temps:
- mobo temp 17C when starting up, so that must be room ambient.
- mobo temp 28C when stabilized, so it's 11 degree more than room ambient!
- cpu socket 39C @ idle
- cpu diode 44C @ idle (even tho asus probe or bios does not show it, can be configured in MBM5)
- if cpu fan is at max speed, both socket and diode are 4C lower
- opening the case door drops diode and socket temp by about 6C
- socket 48C diode 58C when running cpuburn for about 20min

I have not yet found a way to monitor the seagate SATA 7200.7 temperature.

Controlling the speed of the fans seems to be possible with speedfan, not yet fully tested.

Hmm, long post, oh well...

lm

Pete · Post by **Pete** » Thu Dec 18, 2003 5:17 pm

Welcome to the forum.

Good job on your server but why remove the sound dampening material, unless you're having heat problems? I use plain old carpet in my case and it does seem to muffle the sound somewhat.

I don't think you'll see much noise/vibration reduction by replacing the fan screws with rubber washers or grommets, especially if you're running the fans undervolted. But it certainly can't hurt.

About your desktop machine, have you considered replacing the psu fan with a Pabst fan? Cheaper than buying a new psu.

There's a thread floating around here somewhere discussing silent keyboards and mice. I don't have a live-in girlfriend so I don't have that kind of a noise "problem".

And how about replacing those standard case screws with thumbscrews? They sure come in handy if you're always opening up your case.

Others here may chime in to help with your other questions. So good luck and happy pc silencing!

Post by **MikeC** » Thu Dec 18, 2003 5:46 pm

The sources of low freq noise are:

1) larger fans 80mm & higher spinning at med-high speed, especially if they are less than perfectly balanced

2) any hard drive mounted normally. mechanically decoupling HDDs will eliminated most of the low freq noise -- especially w/ a quiet one like B-IV. Am surprised amoung the hf noise from your Samsungs. They must be a different model than the ones I've used in the last few mos -- all SP 7200 rpm models, no whine.

aphonos · Post by **aphonos** » Thu Dec 18, 2003 6:31 pm

MikeC wrote:Am surprised amoung the hf noise from your Samsungs. They must be a different model than the ones I've used in the last few mos -- all SP 7200 rpm models, no whine.

MikeC: I believe the Samsungs of which he spoke were his monitors

not his HDDs. I get some of the same hum/whine with my 955DFs.

lm: Welcome to the SPCR forums!
I agree with Mike that decoupling the HDDs will reduce your noise level. Several ideas can be found in the storage section on the main site or in the Storage forum.

Though YMMV, I'm gonna disagree with Pete's stane (sorry

) that decoupling the fans won't make much difference. In a noisy system that's true, but in a quiet system, every little bit can help. I'd recommend the elasotmer isolators or the rubber mounting sticks rather than using rubber washers, as the latter don't help all that much for fans.

On the Sonata have you cut away any of the sub-bezel or lower area of the front bezel as some other uers here have done? Seems to dramatically improve their airflow.