1/27/2024 0 Comments Sos with hummingsHowever, the replacement monitor wasn't capable of the very high screen resolutions that Jim was using on his two GNR monitors, and it is certainly possible that the additional demands placed on the monitor and its power supplies to provide such high screen resolutions were a significant factor in the level and quality of noise generated. To confirm the source, we substituted the two GNR-brand screens for a different LCD screen of a different make, borrowed from his office, and that produced a substantially lower level of buzz and noise. That suggested that the buzz was definitely being generated by his two LCD screens, but exactly where the noise was getting into the system was far from obvious. On our arrival in Bungay, Jim demonstrated the loud buzzy hum he was getting on the system, and how it disappeared completely if he turned the LCD monitors off. However, when Reviews Editor Mike Senior suggested a visit, Jim confessed to being a 'Hobnob scrooge', and we all know that Paul White doesn't get out of bed nowadays unless there's a pack of chocolate Hobnobs in it! Fortunately for Jim, though, it turned out that Paul was going to be away visiting a certain Antipodean microphone manufacturer, and since Mike doesn't suffer the same debilitating condition as our Editor In Chief, it fell upon him to join me in attempting to find a solution to this thorny problem. Clearly, this was a complicated problem and it sounded like a suitable challenge for Studio SOS. Questions over noisy mains supplies appeared to have already been addressed as well, since Jim was feeding all his equipment via ETA power conditioners. The usual suggestions of moving the LCD screens' power supplies around, using balanced connections to the Fostex speakers, and changing the computer graphics card had already been tried and found to make no difference. Jim had found that jiggling the monitor video connectors or power leads affected the hum (suggesting poor earthing perhaps), and after relocating the monitor VGA cables along the back wall (to move them away from mains and audio cables) the hum level was reduced - although that could just have been a coincidence of remaking the connections, and thus improving the earthing contacts in the process.Ī number of other Forum posters had offered help, but to no real avail. One monitor seemed to create a louder hum than the other, and they produced slightly different pitches too! The only thing that silenced the hum was turning off the LCD monitors or removing their video inputs (in which case they shut down anyway, of course). The symptoms of the problem were intriguing, as the hum apparently remained if the mixer or MOTU 828 were turned off, and it became louder if the Firewire link between computer and monitors was removed. His pair of 18-inch LCD screens were mounted on the wall behind the Topaz desk and hooked directly to a Radeon dual-head graphics card in the PC. Mixing was performed on a large Soundtracs Topaz eight-buss analogue mixer and monitored on a pair of Fostex PM2 active nearfields, with a range of outboard effects units and synths hooked into the system via various patchbays. He described his equipment as being based on a Dell PC coupled via Firewire to an original MOTU 828. He had recently moved house and was in the process of rebuilding his studio equipment into a large room above a timber-framed garage, but he had started to get such high levels of noise that it could clearly be heard in the next room! He was suspicious that the problem might have been caused by two new LCD computer screens, with which he had recently replaced the previous pair of 'legacy' CRT monitors. This month's Studio SOS visit came about because of a post in the SOS Forum in which reader Jim Fish complained of serious hum problems in his studio. The SOS team purge the unwanted buzzes and hums from reader Jim Fish's new studio. This test system picked up none of the noises which the main system was suffering from, indicating that the problem stemmed from earthing problems. To test this, he powered a separate laptop, Jim's MOTU 828 audio interface, and one of the Fostex speakers from a separate plug socket. Jim's studio system was picking up unwanted noises from his new flat-screen monitors, but Hugh wasn't sure whether this was a problem with the LCD screens themselves or whether it indicated an underlying earthing problem.
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