Cocoon Culture No.47



The Quest for Silence : An attempt at eliminating computer generated noise

Background for project is to identify sources and remedies for computer generated noise. Goal is to reduce the noise to an acceptable level for use with audio recording and personal well-being.
To retrace this information in the future use

Starting out :

General : Outset - Sources - Remedies - System specs

PART 1 : Bookmarks :  - Technical - Measurements - Findings - Conclusion - Further - Noise-Killer Info 

Further exploration :

PART 2 - HF PSU noise related.

PART 3 - FAN Doodling - Cab modifications - HD relocation etc.

PART 4 - Cab mods. - HD Noisebox - PSU - Software coolers - Wrapping up system 1 and moving on etc. [  at the end of a road.]

PART 5 - Upgrading - System 2 (Celeron700)

system_upgrade_.htm     - Moving on to a more contemporary system.

Current work documents / areas :

  1. my-star.gif (7523 bytes)system_2_silencing-plan.htm      - Starting out the silencing of the new system (2).Successfully silenced. Stable.
  2. The quest ends. Wrapping up stuff done. Presentation and pictures of creations. Closing remarks.
    [ Q4 CPU Element ] [ DD CPU Element ] [ The Tranquilizer PSU ] [ HDD Noise Box ] [ Cab modifications ]
  3. Evaluate the possibilities for creating a limited number of noiseless units for sale. Too expensive maybe ?
  4. Trying to make some kind of structure in this mess ... Will add pictures, etc. [ photo folder ]

PART 6 - Pilot Project - Building a silent PC using standard components.

[ pilot-project ] >> WEB Report not yet available.<<

Noise survival guide (accumulated knowledge) :

If you are balancing on the edge of a mental breakdown, you may click on the appropriate link here for a quick primer based on the information and experience gathered sofare. [ AAAAArrrrrrrgggggh !!!!! ]

Evaluation of the accoustic properties of some Hardware.

In conjunction with the pilot project a number of standard parts where examined & evaluated. Includes  SilentDrive, NoVibes, Ezra 800, Barracuda IV ++ other tested devices. This information and knowledge about other devices that I've run across are included on this page.
[ review ]

Downloads :

Useful silence related software are kept in the  [ downloads ] [ folder ]. It contains diverse freeware and shareware programs such as software coolers, monitor programs for temperaures, test utilities etc. Basically anything that I've found usefull during this project.

Reference documents :

[ ref.1 ] "Notes on the Troubleshooting and Repair of  Small Switchmode Power Supplies", author Samuel M. Goldwasser.

[ read ] "Diskless Windows 98", author Andre Moreira.

[ folder ] - Diverse external documents gathered from the web.

Links to related sources of information : - Webpage with an informative and in-depth discussion of the topic computer noise ... also has an extensive link collection. Recommended.      - Tidy presantation of C.N. and remedies. Lots of information from a practical point of view.      - Definitly the page for anyone with a 3rd degree desperation level.      -  Lots of relevant information and utilities can be found on overclocking sites.

Chris Hare's Processor Electrical Specifications page.      - Great overview of CPU power consumption.     - Online shop with focus on low noise PC components.      -  A good  article about reducing unwanted background noise in the studio. - VIA's silence page. General & device info.

HANDBOOK FOR ACOUSTIC ECOLOGY - One of the best web publications I've ever seen.

Feedback :

Feel free to make contact if you have any question regarding this document. Any tips & tricks & experiences are greatly appreciated.

Use this address

If you are interested in some of the creations that comes out of this project, make contact on a personal level. All of these objects should be viewed as "functional art", but I have not yet had the time to elaborate this 'concept'.

At the Outset

The subject of this study is an AOpen HX45 cabinet, with an astonishing noise level. Approx. 45 dBA on average. Factory installed Noise Killer works poorly. High noise level on PSU fan. High noise level on CPU Fan. Medium noise level on IBM Deskstar drive.

The noise level have already been reduced to an acceptable level, by using resistors on both fans (CPU&PSU). As well as changing the voltage level for the CPU cooling fan from 12+ volts to 5+ volts.

Status : 06.02.00 - Awaiting ordered parts additional memory, new CPU fan, fan-regulator. Document not published.

Further more need a sensitive microphone to record and identify the various frequency components of the noise sources.

Cool edit will be used to analyze the results. Or some other software. Hypersignal ? if it still works.

Status : 11.02.00 - Parts arrived. Microphone and stand obtained.

Status : 21.02.00 - This document completed.

< a lot of neglected updates >

Status : 11.03.2001 - A silent system has been created. The only source of noise left in the system is that of the drives. A custom made HD noise-box takes care of most it. Main components are a fanless CPU cooling element and a fanless PSU. A new silent psu is under construction since the first prototype was blow up by factors beyond my control (yet another thunderstorm) waisting 2 months of work and ending further measurments.

Sources of noise :

Initially there are three main types of noise that are identified.

  1. Mechanical - Vibrations from moving parts such as fans and drives.
  2. Air-flow - Noise generated from PSU, CPU or Cabinet cooling fans.
  3. Electro-Mechanical - Noise generated from capacitors, transformers or coils etc.- ex. CRT, PSU or tube-lights etc. High pitch.

Main generators of noise are :

  • Fans (Air-flow, vibrations)
  • Drives. (Rotation, vibration)
  • Monitors. High/low frequency noise.
  • PSU-electronics & Transformers.

Observations :

#1 : My Panasonic SL70i have started making an annoying low-frequency "eeee.." transformer sound after a few months of noiseless operation. Question : What is that cause of this change ? I suspect that the scan frequency has something to do with it, as I have observed changes in the noise level when these parameters have changed.
#1 Update : The sound is here to stay. Changed everything. Even videocard. The sound remains. Get another monitor.
#2 Update : According to information found on the net, the cause of the high-pitched noise is due to the vibration of the coils on the CTR-tube with a frequency of approx. 10 kHz. This seems a plausible explanation for the high-pitched noise that I hear. Hummm ...   don't know what to do about it though, but at least it's an explanation as to the source of the noise.
#3 Update : My Panasonic monitor flatlined in less than 2 years. This adds to my list of observed failures, and feeds my sense of experiencing a universal technological   breakdown.

#2 : High frequency tube-light, mounted 1.5 m above floor makes noise. Not measurable ? (Side track, but part of the environment)

#3 : There are an astonishing number of sources of noise. When being conscious about your environment more or less everything makes noise. Everything from lightbulbs (quality dependant), refrigerators, televisions,  etc. Much of it is on a "sub-conscious" level. You don't notice it's presence before you focus on it. In principle I think any kind of electrical device makes noise at some level. I also suspect that there is much noise that pass undetected at it is of a "psycho-acoustic"   nature. I.e. you "can't hear it" or point to where it's coming from, still you can be aware of it's presence ... or even more so it's absence. Mobile phones are a good example of this. I note that my service provider have included a general disclaimer regarding "any possible biological effects" in their terms of use "agreement". Very reassuring.

Remedies :

There are several ways of reducing or eliminating noise.

Reduce the emitted noise from the generators. Alter the operation of the computer.

Temperature controlled fan regulators (Noise killers). Ideal is pulse controlled fan-regulators, but where can they be found ?.

Resistors on fans. (Drawback is resistor heat-dissipation, increasing cooling requirement. Also fans may not operate as intended with a resistor inserted.Generating a different noise characteristic, which may be perceived as more annoying than the previous one.)

Noise Insulation/absorption of/in cabinet. Drives.

Improved cabinet airflow/circulation. Reduced cooling requirement.

Other factors : Reducing drive up-time, more caching, more memory, reducing CPU-clock speed. Change fans.

Masking the noise : Turn on your stereo and play music.

Use ear-plugs.

Get used to it.

Ignore it.

Use external equipment with independent PSU. (e.g. Modems, CD-ROM's, ZIP-drives). => Reduce the PSU load and case cooling requirement.

Throw your computer through the window. Scream and make funny twitching motions with your facial musculature, while you at the same time repeat in a hysterical and incomprehensible voice : "Noise ... noise ... noise ...".
Then after a quick and hopefully brief stay at an mental institution, you sue (in the "good" spirit of the modern age) the manufacturer for psychological damages.

Alternatively if you think this is to much hassle, or feel nervous about the prospects of what a psychiatrist might do to your mind, body, spirit and soul : Get a portable laptop computer instead.

Copyright 1999-2002 Cocoon culture no.47 . All rights reserved.
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