Noiseless PC

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Contents

INTRODUCTION

At NOTAM, we have recently built two new workstations, called Louis and Bebe. These computers have the following features:

  • Completely inaudible, at least in an office environment and listened to from a one meter distance. We also think they should be completely inaudible in most studio environments.
  • Provides good real time performance. We got "glitch-free" audio down to 8ms latency out of the box with Planet CCRMA's real-time Linux kernel, but far better results can most likely be achieved with better sound card, other drivers and other options. (This was tested with both Ardour and Pd, and jack reported 0 xruns .)
  • All fans run at constant speed. In other words, the machines do not make more noise when working harder.
  • Stable. Both machines have been running day and night since 6th of November 2009.

PARTS

The parts listed below amounts to around 9000 NOK per machine. A less expensive machine can be assembled by replacing the i7 system with a 775 system, or an AM2/AM3 system from AMD. One should however be aware that AM2/AM3 processors tackle less heat, and that fewer CPU coolers are available for the platform. So for a noiseless systems, Intel is perhaps preferable to AMD.

Nymaskin deler.jpg


  • Hard drive:
  Western Digital Green Power 1TB, Sata 3 Gb / s, 32MB Cache 
  http://prisguide.hardware.no/produkt/western-digital-caviar-green-1-tb 
    
  According to http://www.silentpcreview.com, this is the quietest available hard drive. 
  Nevertheless, it turned out that the hard drive, without any comparison, made the most noise in the system. 
  If the machine is to be situated in a recording studio, it may be necessary to use an 
  SSD disk instead to achieve (almost) complete silence. (more on this below) 
  • DVD Writer:
  Lite-On DVD+RW burner IHAS124-19, SuperAllWrite, 24x8x16DVD+RW, SATA, Black 
  http://www.komplett.no/k/ki.aspx?sku=494479 
  • Motherboard:
  ASUS P6T SE, X58, Socket-1366 
  http://prisguide.hardware.no/produkt/asus-p6t-se 
  • Processor:
  Intel Core i7 Quad Processor i7-920, 4.8 GT/sec, 8MB, BOXED 
  http://prisguide.hardware.no/produkt/100942 
  • Memory:
  Crucial DDR3 BallistiX 1600MHz 6GB Kit CL8 BallistiX w/3x 2GB modules, CL8-8-8-24, 1.65V, 
  http://www.komplett.no/k/ki.aspx?sku=479399 
  • Mouse Pad:
  Roccat Taito Mousepad, Heat-Treat Nano Pattern, 400x320mm 
  http://www.komplett.no/k/ki.aspx?sku=498327 
    
  Very little friction sound! 
  • Video card:
  ASUS Radeon HD 4350 512MB DDR2 Silent PCI-Express 2.0, DVI, native-HDMI, HDCP, low-profile " 
  http://www.komplett.no/k/ki.aspx?sku=460397 
    
  Fanless. 
  • Computer Case:
  Antec P183 Advanced Midi Tower Black 
  http://prisguide.hardware.no/produkt/110742 
    
  Good thermal properties (dust filters, fan in the ceiling, room for big fans, power supply in the bottom).
  It also resonates very little. 
  • Power supply:
  Silverstone SST-ST45NF 450W PSU ATX 12V Ver 2.3, Fanless, 80 Plus Bronze, 1x PCIe 
  http://www.komplett.no/k/ki.aspx?sku=481300 
   
  Alternatively, SST-ST40NF 400W. (PS-data or DustinHome)
    
  Apparently there is a lot of money to save by buying a power supply with a fan. 
  But experience with power supplies from Corsair, Tagan and Mist - all 
  advertised and reviewed to be very quiet - shows that none of these are quiet 
  enough to be placed in a machine that is supposed to be noiseless. 
  • CPU Cooler:
  Prolimatech Megahalems Socket 775 and Core i7 (1366) 
  http://prisguide.hardware.no/produkt/prolimatech-megahalems 
    
  Best in test according to www.silentpcreview.com 
   
  Alternatively: Noctua DH-14 (warning, we have tested this one, and so far it does not seem to be able to compete with the Prolimatech using very low-speed fans!)
  • CPU fan:
  Noctua NF-P12 120mm 
  http://prisguide.hardware.no/produkt/91200 
   
  (Not necessary to buy separately if using the Noctua DH-14 instead of the Prolimatech Megahalems)
  • Case fans: (2 pieces, used instead of those supplied with enclosure)
  Noctua NF-S12B ULN, 120mm 
  http://prisguide.hardware.no/produkt/110718 
    
  These fans can be adjusted to run at very low speeds. 
  • Voltage regulators for the fans: (3 pieces)
  Cooltek FanMate voltage regulator 
  http://www.netshop.no/aspx/produkt/prdinfovnet.aspx?plid=118053 
  (alternatively: http://prisguide.hardware.no/produkt/23310) 
  • Sound Card:
  M-Audio Delta44
  http://www.m-audio.com/products/en_us/Delta44.html
    
  alternatively:
  SDM, USB sound card 
  http://www.netshop.no/aspx/produkt/prdinfovnet.aspx?plid=123539 

Most of these parts are sold by www.komplett.no, but the CPU cooler, the sound card and the voltage regulator are in Norway only sold by Netshop and Microplex. The M-Audio soundcard is sold by several netshops, you can f.eks. get it at Luthman.

CONSTRUCTION

Case Fans

We started by replacing the fans already installed in the case with two Noctua NF-S12B ULN fans:

Before
After

We run the case fans at a speed of 400 RPM each.

These Noctua fans are able to run at very low speeds without failing to start when powered on. (around 400 RPM seems to be the minimum.) We adjust the fan speeds by using one of the supplied resistors (preferably the one with the bigger resistance value, which is marked by a black connector), and fine-tune with the "Cooltek FanMate" voltage regulator.

It is also important that these two fans suck air out of the cabinet, and not the other way, for new air to be drawn in through the dust filters in front and make warm air rise naturally upwards.

Unfortunately, it was not possible to use the included rubber mounts to mount the fan in the ceiling. However, the NF-S12B-fans seem to resonate minimally when running as low 400 RPM (minimal difference whether the fan is on or off), so it was not a disaster to have direct contact between the fan and the chassis in this case.

Power Supply

The power supply is placed in a separate room at the bottom of the case, causing the PSU not to be warmed up by the CPU and motherboard, and to some extent vice versa. This is especially important since our power supply is fanless and has a reputation for becoming very hot.

Nymaskin psu.jpg

In addition, we chose to mount the power supply upside down to let openings in the PSU face upwards. Only one of the largest surfaces on the PSU has got openings, so this configuration should make it easier for warm air to escape.

Motherboard and CPU Cooler

Nymaskin hovedkort.jpg

Before attaching the mother board to the computer case, a back-plate for the heat sink must be screwed to the backside of the motherboard:

Nymaskin bakplate3.jpg

After mounting the CPU, a dash of cooling paste is attached to the CPU cooler and the CPU itself:

Nymaskin pasta.jpg

... before the CPU cooler is attached to the board:

Nymaskin skrukjĂžler.jpg

CPU fan

A pair of metal clips was included with the CPU cooler for fan attachment:

Nymaskin vifteklips1.jpg

But these clips caused the CPU cooler to resonate, which in turn spread further on to the motherboard and chassis. To fix this problem, we used the four rubber mounts included with Noctua fans:

Nymaskin gummi2.jpg
Nymaskin gummi1.jpg

... and secured the fan to the heat sink with (a slightly slack) copper wire:

Nymaskin kobber1.jpg
Nymaskin kobber2.jpg


We run the CPU fan at a speed of 700 RPM.

Noctua NF-P12 seems to start fine all the way down to 600 RPM, perhaps even lower, but at 600 RPM the temperature of the processor turned 81 degrees under stress, which made us worry that the processor could be too hot in the summer. At 700 RPM, on the other hand, the temperature only reached about 75 degrees, and all the CPU cores remained below 79 degrees (measured with Real Temp) when stress testing with the software prime95. The stress test was run for several hours. This should be good enough. (By comparison, this system was measured to run at 90 degrees!). Furthermore, it was not possible to hear a difference in noise between 600 RPM and 700 RPM at 1 meter distance from the machine.

We also tried to use two NF-S12B-fans running at 400RPM in a so-called push-pull configuration, instead of an NF-P12 fan running at 700rpm. But in this configuration, the temperature rose well above 80 degrees and could therefore not be used. (NF-S12B-fans have fewer blades than the NF-P12 and could probably not maintain high enough air pressure through the tight fins on the cooler [1]). Furthermore, it didn't seem like two NF-S12B-fans were much quieter than a single NF-P12 fan either.

The single NF-P12 fan, which we ended up with, was placed on the right side of the CPU cooler so that air is pushed in the left direction through the heat sink. We believe this is the most effective layout since the case fans are sucking out air both above, and to the left of, the CPU heat sink:

(We are not quite sure where the air actually enters the machine, but we hope a lot of it comes through the two dust filters in front, although that might very well just be wishful thinking...))

Note that a newer CPU cooler, Noctua DH-14, is larger than the one we used in this setup. Testing on a different computer indicates that the Noctua DH-14 heat sink might be able to run fanless in this setup.

Hard Drive

For data storage, we chose to use a Green Power hard drive from Western Digital. According to http://www.silentpcreview.com, this is the most quiet hard drive. Unfortunately, it turned out that even the quietest hard drives made more sound than all the other parts combined, even though the Antec case seems to have good sound isolation for hard drives:

Nymaskin harddisk.jpg

Therefore, we would recommend using an SSD drive (SSD = Solid State Drive, thus no moving parts) instead. SSD drives cost a bit more, and their life span is possibly somewhat shorter, but in return they are much faster than conventional hard drives. In addition, SSD drives are totally silent.

The writing speed of different SSD drives vary though. It is wise to check out out minimal write speed and maximal latency that may occur during writing. A good overview of the benchmark results can be found here: www.tomshardware.com

Video Card

The P6T SE motherboard has three PCI Express slots. The first PCI Express slot is very near to the CPU, the second slot a little bit further away from the CPU, and the third one quite far from the CPU. Ideally, we would mount the video card (which gets very hot!) in the third slot to get it as far as way from the CPU as possible, but since the third slot is only of the "x4" type, we chose not to. Instead we mounted it in the second.

RESULTS

Noise

  • If placing an ear so that it touches the machine, we hear some resonance plus a weak swooshing sound from the hard drive. (remember that the machines are not equipped with an SSD drive!) These sounds could be reduced by using one of these or these.
  • When we disconnect the hard drive, we only hear a relatively weak resonance sound from the computer case generated by the fans.
  • Near the case fan outputs we also hear a little air borne noise, probably caused by air forced through the case fan grills.
  • Standing about one meter away from the computer (with the hard drive turned on), we could not hear anything. (At least inside the NOTAM office environment, which has some background noise)
  • We could also hear hard drive seek noise from a few meters away. However, this sound was only heard when many large packages were installed simultaneously in Linux. We could not hear anything while recording sound to the hard drive or booting the OS as long as the machine was placed under the desk. We have experience with using one of these, which we know can remove most hard drive seek noise. However, since these computers may be moved around now and then, we chose not to use the Sunbeam Harddisk Silencer, to lower the chance of damages.
  • The machines seem to be free of electrical noise.

With that said, we would probably hear whether the machines were switched off or switched on if we had listened in an anechoic chamber (i.e. a room that is completely silent). However, our machines sound quite enough for most recording studio control rooms, especially those equipped with a ProTools box (which are very noisy in comparison).



(Note that the noise level during filming is almost constant. It is the the microphone that makes the noise!)

Temperatures

  • CPU idle: 37.5
  • CPU stress: 75
  • During stress test, the PSU only gets half-warm. This is probably due to the bottom placement of the power supply.
Nymaskin bios.jpg
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