Should you want to discover the exact frequency of YOUR hum download and install this instrument tuner:
www.aptuner.com/cgi-bin/aptuner/apmain.html This tuner detects dBC range modulation and harmonics to one-tenth of cent in real time - No recording though, sorry folks. If you can't install it, don't ask me to tell you how. I gave with that a long time ago. You may have increase the gain on your mic in Windows. On Dec 3, 5:28 pm, Vic <[email protected]> wrote: > This is why you can hear it and others can’t – You’re a dBC Receptor. > Seems like it's regulated by ANSI in the USA - Now there's something > to think about folks! Something new to trip "them" up on? > > Below is a portion of a document at this website's URL: > > www.efsec.wa.gov/bpcogen/DEIS/3.%209%%20Noise.pdf > > Humans respond to a sound's frequency or pitch. Environmental noise is > composed of many frequencies, each occurring simultaneously at its own > sound pressure level. As measured by an electronic sound level meter, > frequency weighting combines the overall sound frequency into one > sound level. The commonly used frequency weighting for environmental > noise is A-weighting, or dBA, which approximates how an average person > hears sounds. C-weighting, or dBC, is a measure of the lowest > frequencies of sound and vibration. Low frequency noise is usually > described as humming or engine-like sounds or a feeling of pressure or > vibration. > > How 'bout that?! > > Impact Criteria for Low Frequency Noise > Although the state of Washington regulates low frequency noise through > noise regulations using the A-weighted decibel scale, the American > National Standards Institute (ANSI) presents recommendations to > provide protection from low frequency noise disturbance in Gas Turbine > Installation Sound Emissions (ANSI 1989). ANSI recommends limiting > noise levels at residences near new gas turbine facilities to 75 to 80 > dBC. > > As with the original Golder modeling study, the newer Hessler modeling > also evaluated low frequency noise levels at the receptors. In > general, the new modeling results indicate that low frequency noise > from the cogeneration facility (C-weighted sound levels and the lower > frequency levels) would be similar to or less than the levels reported > by Golder for the original project configuration. Consequently, both > studies conclude that low frequency noise would not reach > perceptibility thresholds at any of the residential receptors. > > The normal threshold of perceptibility for low frequency noise and > vibration is 75 to 78 dBC (ANSI 1989). The ANSI recommends C-weighted > plant levels should be significantly below 75 dBC at residential > receptors. -- You received this message because you are subscribed to the Google Groups "Hum Sufferers" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/hum-sufferers?hl=en.
