[sdiy] OT: The best ways to silence a PC?

[Czech Martin]

There are amanufacturers who make enclosures that damp
most of the noise. The front is usually a glas plate door,
so you can open the thing and put your CD in, etc.
The cables are run through holes or slots with rubber lining,
so no noise wave can come through (well, some noise will get
through). The PC must stand on rubber bumpers in order
to prevent mechanical noise leak.

So far such an enclosure would not be too difficult to build.
The only thing is that you need a high volume, low speed
(tangential) blower to keep the enclosure cool.
Or a water cooler. Most rules for speaker enclosures apply.

The advantage is that you do not need to open your PC, or modify it.

Of course, damping of the CD/hard drives (which transmit most of
the noise to the chassis) is always a good thing.
I simply did not mount them with screws, but they lie on a slice of foam.
You need to remember this when moving house, of course!

Be aware of heat!!
Most drives tend to get very hot today, so I will mount another blower
to cool them. PSU temperature is sometimes much lower then drive temperature,
this can shorten life time if the PSU blower is regulated with the
PSU temperature. I have measured 60C for one drive and 40C for the PSU
after 6 hours of service.


Perhaps you do not have to go so far. Assuming that every rattle in the
PC enclosure is damped, there is a good chance that a 4 sided wood box
will do the trick. The front, sides and top are covered with wood.
The rear will reamain open (so no cable problem). Perhaps you make the enclosure a 
bit longer than the PC is. The inside should be covered with absorbing
foam. I assume the the PC will stand with the rear side to the wall.
Add another damping element to that wall, a little wider and higher
than the PC is. This should damp the reflections.

My Ultra Sun at work is *not really silent*.
Placing it under the table has damped the noise to an acceptable
level, allready. Desktop machines suck in this way.


When I was young I had to deal with a video sequence engine. This 
was a monster cabinet, 2x19" wide and 2m tall. It had lots of DRAM
(I guess 64k chips at that time) and an ECL processor.
It could play video sequences ot of DRAM (I think 20s or so),
in all possible existing formats (NTSC, PAL) and experiemental
formats (HDTV). It was all programable.

It could also play examples of picture compression, motion compensation
etc., these where computed with weeks of CPU time on a Digital VAX.

Anyway, this cabinet was water cooled. In the morning, you turned the water
tap on, and off in the evening. The machine was cooled with chilling cold
water from the main pipe, no closed circuit.


One morning I forgot the water and the chips almost got fried...
I noticed it, because timing went haywire and the picture goofed up...


Those where the times...


m.c.




-----Original Message-----
From: ASSI [mailto:Stromeko at compuserve.de]
Sent: Samstag, 10. Mai 2003 16:30
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] OT: The best ways to silence a PC?


On Saturday 10 May 2003 10:09, Glen wrote:
> This is mostly off topic, but it does affect many of the people on
> this list. It also has an impact on many people's ability to hear the
> music they make, without the annoying noise of a PC that might be
> running in the same room. Often that very same PC is instrumental in
> either creating or recording the music in question. This is also a
> DIY project--maybe this IS on-topic after all.

For some seriously DIY PC silencing a colleague of mine has done take a 
look at:
http://www.foeste.net

> What I want to do is gather together ideas of how to best silence a
> PC.

The most noise is there because you need to remove heat. So a good 
start is to use components that do not produce much of it, because that 
makes the problem of removing the heat with minimum noise considerably 
easier. Next, people tend to concentrate on fans, but forget that you 
actually need to move the air around the components you want to cool 
with a certain speed and you also need to keep the total airflow rather 
high. Air is a terribly inefficient cooling medium and at the required 
high speeds and flows it will produce quite a bit of noise all by 
itself. The computer I'm typing this on makes not much noise, probably 
around 30-35dBA - most of that is actually from the airflow itself, as 
you find out when you briefly interrupt the airflow by blocking the 
exhaust. I replaced the CPU fan with a Verax and kept the original PSU 
fan. Back at the university I've had a muffler box for my workstation, 
which basically provided forced airflow to the unmodified workstation 
inside, but controlled the turbulence noise by carefully designed 
intake and exhaust with a large diameter. A box like this would not be 
terribly difficult to DIY I reckon.

Next up are liquid cooling (see above) and heatpipes. Both are 
cumbersome to dimension, expensive and badly matched to the electronic 
components in a computer that are all designed to be air cooled. I've 
seen a DIY alcohol heatpipe for the first Alpha AXP processor at DEC 
CRL in Palo Alto while visiting a friend there a few years ago... 
Liquid cooling helps to get heat away from a few chips quickly, but the 
rest of the computer still needs airflow, especially the voltage 
regulators right next to the CPU. Nevertheless there are a few small 
companies that make computers that are cooled by heatpipes. They are 
expensive as on top of the custom made parts for cooling the PSU 
generally is replaced by a passively cooled one for industrial 
applications. But since the enclosure can be completely sealed, these 
are the most quiet computers you can get today.


Achim.
-- +<[ Q+ & Matrix-12 & WAVE#46 & microQkb Omega sonic heaven ]>+ --

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