The components in a PC can get very warm, especially when the
CPU is under stress and the hard drives are reading and writing large
amounts of data.
In a
DAW
the CPU is often stressed to a high degree, but excessive cooling will
make the machine noise from the computer far to loud to hear the finest
details in a mix. For every Decibel of noise audible from the computer,
a
Decibel of detail will be masked.
Most of these problems can be easily addressed provided they are
understood.
I should stress at this point that performing modifications on your power supply will more than likely invalidate your warranty.
There is an awful lot of hype surrounding the marketing of quiet PC solutions. The truth of the matter is that there are only two forms of noise that come from a computer:
The power supply is usually the loudest component and is probably the most involved to bring to a quiet sound level, but it is wise to upgrade from a "standard" power supply to a model capable of a reasonable power-output in the case of computers which will be used as DAWs. Quite apart from the fact that the multiple processor, or multi-core computers which tend to be used by the DAW community will need more power than an "average" machine, we also require multiple hard-drives, maybe additional cooling, a number of peripherals, some of which may be bus-powered from USB or Firewire sockets. All of these things require extra power and more powerful supplies tend to heat up more.
The key to getting a good, quiet power supply lies in making sure that the fans are large. They must also vary in speed depending on the load placed upon them. Don't be tempted to get a no-name brand with flashing LEDs. Apart from providing a tell tale sign that you have an expensive computer in your studio, they quite often don't perform as expected and can be responsible for dramatic loss of data if they give up the ghost. Large fans are better as a rule because they can move more air at a lower rotataion speeds. Power supplies have come a long way in the last few years. Now quieter computers are a far more common requirement since consumers use them more oftem for multimedia applications. They are more often in a customers leisure environment than was the case some years ago. It is quite possible to change the fans in your power supply for better and quieter ones. There are a number of anti vibration kits available for both fans and PSUs. They mostly consist of a silicon gasket and a set of normal, but slightly longer bolts. These will not make your computer any less noisy. At best they will only stop the PSU or fan from vibrating against the surface to which it is fixed. Most of the vibration will be transferres through the fixing points. As with any component which causes the computer case to resonate, isolating the component from the case is the only effective way to stop it. All is not lost! in the case of a computer PSU the fans are the only moving component, so in fact, it is quite possible in most cases to fit anti-vibration mounts to the fans. These are available at around £4 for 8, or £35 for 100 at Quietpc.com amongst others.
The next most common cause of noise in a more powerful PC will probably be the case fans. The same rule applies. Larger fans make less mechanical noise because they do not need to rotate as fast. Brushless fans are much quieter than the brushed variety. They are also more reliable in operation and last longer. Often a great amount of attention is paid to the diameter of the cooling fans, but the depth is just as important. A fan will move even more air if it has a fan blade which spans over 25mm or 30 mm than a 20mm blade. The fans supplied in even some of the most expensive cases are of relatively low quality and many availble from PC suppliers are just cleverly marketed and packaged. Often the manufactureres state that they are silent, but this is in fact not true. As a rule the quiestist and most reliable fans have sleeve bearings rather than ball bearings.
One of the best makers of Fans is Pabst, the famed makers
of
the motors in many professional tape machines. They have an excellent
range which are available through Radio spares in the UK
here
They manufacture both an 80mm and 120mm fan with noise levels of 10dB
and 12dB respectively at a cost of around £15 each. These fans are low
speed models, but they still move more than enough air to cool the
hard-drives which carry so much precious data
Another way to ensure that air makes as little noise as possible is to replace the flat metal cut-out in front of the fans with either nothing or a wire grill these are also available from electronics specialists.
Some manufacturers seek to pursuade us that insulated cases will be quieter. Anything which has additional insulation against sound emmission will automatically also store heat if the air-flow through the case is impaired. This in turn means that a computer will require more cooling and will likely make more noise as a result. At best, building a computer this way is likely to form a trade off of any reduction in mechanical noise to that of fan noise.
Close inspection of the beautifully machined cases housing the Macintosh computers reveals that much as consumers are often encouraged to use sound dampening techniques to obstruct noise from leaving a computer case, the reverse approach can be more effective. If it is possible to restrict the airflow as little as possible, convection removes a great deal of the warm air from a computer effortlessly and silently, this removing the need for high speed fans at all. The Mac. case is almost entirely perforated, presents little resistace to airflow and is a very quiet machine.
The Coolermaster Stacker series of cases are similar in this respect, having twelve removable, perforated grills on the front, each of which can be removed and replaced with a drive bay. Another case, the Lian Li PC - A17A is similar in design. Both the Coolermaster Stacker and the Lian Li PC A17A come with and isolated hard drive chassis which accomodates a 120mm fan. and an opening for an 80 mm fan at in the top panel. I have a stacker myself. In practice I have found that convection is enough to carry heat away from the top of the case, so the supplied fan is disconnected.
Most PSUs draw heat from
the underside and deliver it through the supply fins and exhaust from
the back of the case. This also has the effect of drawing
warm air away from the processor heatsink, so in most circumstances the
rear case fan next to the processor will provide some additional
cooling, but may not be entirely necassary. At the expense of a degree
or two of heat, this fan may be disconnected, or removed entirely.
Just like the rest of the components in a studio, it is often better to look for a specialist supplier for a particular component rather than going to the nearest supplier. Often the cost of a superior component will be less than you think and the quality higher. In the case of PC fans, undoubtedly the manufacturer of the best and quietest fans is Ebm Pabst. I must stress that this is not an advertisement, rather, simply a fact.
Processors have become far more efficient over the last few years. They now use much less power, and in turn create less heat. In normal circumstances most motherboards can very the speed of the processor fan. These two improvements reduce the need for large expensive heatsinks under "normal" situations, but when e processor reaches the high load that a DAW user might expect the supplied fans can make a terrible racket!
There are some very elegant (and expensive) solutions in the shape of designer heasinks, quick dispelling versions such as the Zalman and Arctic ranges, heat-pipe solutions which seek to propegate the heat away from the processor and cool the liquid over a larger surface area with a larger fan and many others, but there is also a perfectly acceptable solution which works admirably.
Fan adapters are available to adapt 60mm, 70mm fan mountings to 80mm fans at a cost of around £4. These enable the user to mount much quieter and more efficient fans with a larger throughput of air directly into the mounting holes left behind on the heatsink when removing the stock fan.
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