Many computer users have run into the issue of whining LCD monitors. Usually, it does not occur when the monitor is set to full brightness, which is usually too bright for most users. The natural response is to turn the brightness down using the monitor's controls. That's when the monitor can start to emit some high frequency tones, which are described most often as buzzing or whining. The noise usually gets worse the more the screen is dimmed.
It can be piercing and annoying enough to overcome even relatively high ambient noise. If you've spent the time and effort to study the information on SPCR and managed to achieve super-quiet performance in your computer, this whine can be absolutely frustrating. In short, it can drive people crazy.
The source of the problem appears to be components in the electronic circuit which controls the brightness of the CFL bulb that lights most LCD monitors. Most likely, this is some form of PWM (pulse width modulation) circuit, a very useful tool that, alas, can have negative side effects. For example, while it allows a fan to start reliably at unusually low speed, an improperly matched PWM control circuit can cause a DC fan to emit more clicking, buzzing and chattering noise as it is slowed. A similar effect may be happening with the monitor CFL bulbs. To modify this electronic circuit in order to reduce or eliminate the whining noise is an impossible challenge for most users.
Thankfully, there is a simple workaround within the software controls bundled with most video card drivers. The color adjustment screen in the display characteristics control panel also provides a brightness setting. Using this control reduces the brightness in the video card output. This bypasses the monitor's electronic control circuit, which can be left at maximum brightness, thus eliminating the noise. It's an approach that works even with years-old video cards such as a GeFore 4 MX onboard video.
The brightness setting in the color window of the Catalyst software for my ATI graphics card is set to -51, which makes the BenQ monitor perfectly bright for me while bypassing that monitor's infernal whining brightness control.
This workaround will obviously not work for LCD monitors that whine even at full brightness. A replacement with another sample or model is recommended in such cases. We have not tried replacing the CFL bulb of afflicted LCD monitors; it probably is not the cause, however. Interestingly, the whine of CRT monitors can usually be reduced by setting its internal brightness control down. It's also not clear whether any LED-lit monitors suffer the same problem.
CAUTION: If you are an image professional (or advanced amateur) who relies on color accuracy, this may not be a good solution. For details, please see the discussion in the forum linked below. If you find the color degradation with this approach to be serious, you may also want to try a combination of both monitor hardware brightness control and video driver software brightness reduction. With a decent monitor, for typical computer uage, you should be able to find a happy compromise between image integrity and aural peace.
Participate in our Quiet / Noisy Monitor Survey
Please help us help you! The SPCR staff and lab can only examine and report on a finite number of products. Reader contributions can expand our reach tremendously. Everyone viewing this page has a monitor. In the forum discussion linked above, please post the make and model of your monitor and whether it whines. If it does, describe the degree, nature and conditions. As this log grows, everyone can benefit by using it as a quick reference. When it gets big enough, we will turn it to a table with multiple models, samples and ratings, and keep it uptodate. It will become a highly useful resource for quiet monitor seekers.
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We continue to explore the issue of high frequency tonal noise from many computer components. As we approach ever lower noise levels, this electronic whining often becomes critical; in "normal" (read: noisy) computers, it is masked by the noise of fans and hard drives. Power supplies, motherboards and video cards are the other main sources of electronic whine. The whine is often associated with power components, usually capacitors and coils. Poor circuit design is probably at fault; electronic resonances in circuits can cause the components to vibrate or ring, and the whining we hear is directly related to that ringing.
We hope that this is the first, not the last or only, article at SPCR to tackle the issue of electronic whining in computer components. If you have any solutions to offer, please share them with us, by email or in the discussion forums.
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Discuss this article in the SPCR forums.
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