Trev and John - Just trying to help fellas...... AP Tuner - The algorithm extends into the dBC range, is compact, and therefore VERY fast. What you see are the inter/subharmonic sine waveforms. You will discover YOUR actual noise's frequency by simply deciding which harmonic of 50/60Hz it is closest to (100/120, 150/180,200/240, etc.), as in NOT above approx. 30Hz, and subracting what you see on AP Tuner from that harmonic. The "slider" on the left (They might have made it more than just a line!) and it's associated moving blue bar indicates the energy level that is going into your computer's sound card - It in no way reflects the energy contained in the "Hum". It does help to be able to see your enemy...........
John - Partially finished buildings are probably not yet connected to mains electricity as such the "Hum" can't get into the wiring as there is no circuit BACK to the mains, which is what it's looking for (OK so the Hum is inanimate, but you get my drift). Anybody look at The Mosquito website yet? On there it explains the different human hearing capabilities and has sample sounds labeled by age group (at the bottom of the Home page) to prove it. On Dec 14, 3:43 am, John Dawes <[email protected]> wrote: > I can confirm the observations made by Vic moving in and out of an > open door. > Some time ago an experiment was carried out by a group of seven Hum > sufferers of which I was a member. We used buildings of various shapes > and sizes and we used both open doors and windows. It was easily > observed that as the head passed under the lintel of the open door or > window a dramatic change in Hum level took place. The movement > required was quite small, about one foot was sufficient to detect the > change. However, when the experiment was tried on partially > constructed buildings the effect was not observed > > On Dec 14, 7:07 am, Trev <[email protected]> wrote: > > > > > Thanks for tips Vic. I hadn't realised that the slider on the left > > sets the recording threshold so now can see results on the plot too. > > The pulsing effect at ELF resembles the same response I mentioned > > earlier on the files that are no longer on here. I searched for them > > on my old disks but no joy. > > I will try I and get some time in on this utility- as it is easy to > > use, and actually deceptively sensitive, at the frequencies of > > interest to us here. > > > On Dec 14, 12:22 am, Vic <[email protected]> wrote: > > > > One real simple test I did that proved it was a real noise: Stand in > > > your open patio door, one foot outside, one foot inside. Swing your > > > head and body, so that it's outside for a couple of seconds, then do > > > the opposite. It's generated outside, then gets in your house wiring. > > > > Second simple and free test: Go find a 138KV overhead electricity > > > transmission line, 3-phase (6 cables), 3 copper (green probably and > > > the live), 3 aluminum ( grey). Stand under them looking along them. If > > > the Hum is going you will hear it in front of you and behind you. Walk > > > and the Hum appears to stay at the same distance from you in both > > > directions as you do. > > > > 3rd simple and free test: Download AP Tuner 3.8 (It's freeware that > > > you pay for if you like it). Install and run it on a laptop computer > > > with a built in mic. you will see your 58Hz Hum - It bounces back and > > > forth between B1 and Bflat1. You may have to go into "Sound" in > > > Control Panel (Windows) and up the mic boost (volume) by 10 or 20dB. > > > but you'll pick it up every time! > > > > It's a real noise, you hear it normally with your dBC hearing > > > capability. > > > > On Dec 13, 5:23 pm, "R.D." <[email protected]> wrote: > > > > > FYI, I hope to hear back from Lin on my observations and questions. > > > > There is a mechanism where the ear can produce its own feedback sound. > > > > > [email protected] > > > > Low-frequency modulation of distortion product otoacoustic emissions in > > > > humans > > > > Lin Bian and Nicole M. Scherrer > > > > Auditory Physiology Laboratory, 3430 Coor Hall, Department of Speech > > > > and Hearing Science, Arizona State University, Tempe, AZ 85287-0102 > > > > Contact Information: E-mail: [email protected], Tel: (480) 727-0650, > > > > Fax: (913) 965-8516http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612004/ > > > > > Hi Lin, > > > > > I think I am observing on a regular basis a otoacoustic emission at 58 > > > > Hz at my home in MD. Since in the ear isolation ear phones and shooting > > > > ear protectors seem to eliminate the hum sound, my guess is there is a > > > > real sound of a very low level penetrating my home and initiating the > > > > 58 Hz hum I hear often. Here are my latest observations, let me know > > > > what to try next. > > > > > The hum seems to be louder in the center of the room and less near the > > > > floor. Bending over forward stops the hum. Moving the head quickly side > > > > to side (no) momentarily stops the hum. If a low hum noise comes on, > > > > like from my heat pump or refrigerator the hum is overcome by this > > > > sound but returns after it stops. Playing music partially stops the > > > > hum, but high frequencies above voice frequencies are less effective > > > > and bass sounds more effective. But with low volume music, the hum > > > > comes back between louder passages of music content. Quiet nights, the > > > > hum is heard outside, but real hum noise can also be heard as I live on > > > > the C&D canal and ships go by at random times. The ships are pretty > > > > quiet but some can be heard for miles as another more real hum and > > > > slowly subside. The hum can be heard in all rooms and the basement and > > > > in a closed car with the engine off. I have only noticed it at my > > > > residence and can no hear it at work. Other sources of low frequency > > > > noise can be heard in addition to the hum and can be directionally > > > > isolated. The hum is non-directional for the most part. > > > > > So I am thinking the hum is real and either a outside source that my > > > > ears are amplifying and making more noticeable or there are some > > > > outside sources that are causing an otoacoustic resonance within both > > > > ears that will not dye out under typical conditions. > > > > > Can you suggest any other simple tests I can try to figure out if there > > > > is an external source initiating this hum? > > > > > I tried using a large 12 inch woofer as a microphone connected to the > > > > isolation ear buds and although tapping the woofer cone could be heard, > > > > no hum could be detected. Is there an inexpensive 58 Hz capable > > > > microphone available that I can connect to the noise isolating ear buds > > > > to determine if there is an outside sound source causing this hum? It > > > > would have to be capable of detecting sounds at 58 Hz that are about > > > > 1/2 to 1/3 the loudness of rubbing two fingers gently together at the > > > > ear. > > > > > Thanks for any help with this, I do not remember hearing this type of > > > > regular and same intensity hum anywhere else I have been except for > > > > that week in Vermont on Mt Stowe. > > > > > Sincerely, > > > > Ralph > > > > > ---------------------- > > > > definitions: > > > > > The fine tuning mechanisms involved in the normal processing of sound > > > > in the cochlea are non-linear, hence combination tones are generated > > > > inside the cochlea when a pair of low-level pure tones with > > > > neighbouring frequencies f1 and f2 is used as a stimulus. Their > > > > detection as sounds in the ear canal proves that they undergo backward > > > > propagation in the cochlea and through the middle ear, and the > > > > non-invasive measurement of the combination tone at 2f1-f2, called the > > > > cubic difference tone (CDT). > > > > > Low-frequency modulation of distortion product otoacoustic emissions > > > > (DPOAEs) was measured from the human ears. In the frequency domain, > > > > increasing the bias tone level resulted in a suppression of the cubic > > > > difference tone (CDT) and an increase in the magnitudes of the > > > > modulation sidebands. Higher-frequency bias tones were more efficient > > > > in producing the suppression and modulation. > > > > >http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2612004/-Hide quoted text - > > > - Show quoted text - -- 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]. 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