I have also experimented recently using a frequency generator app on my iphone, and headphones. Between 55-60 Hz, I was able to tune the frequency to match the hum by reducing the 'beat' frequency… exactly like you would do when tuning one guitar string to another. When matched, I played with phase, hoping that I would be able to cancel the hum, but there was always another (higher) frequency present. I also tried at around 120 Hz with the same outcome. Although there was another frequency present once I matched the lower frequency, I have to admit that the remaining frequency was MUCH more tolerable than the lower frequency hum, which WAS imperceptible.
As a future experiment, I would like to play with a multi-channel frequency generator, and overlay sound forms to see if I can eliminate the hum altogether by frequency matching as described. Incidentally, the volume that my headphones were set to, to match the level of the hum, was VERY LOW… almost zero. This was actually very surprising, as I perceived the hum as much louder than it actually was. This leads me to conclude that there is definitely an aspect of the brain 'tuning in' to find the hum. Those who have heard the hum (or those seeking to hear it), once heard, will train their brains to hear it simply by listening for it. And the more you attempt to hear it, the more powerful you brain will be in picking it up. I believe in this sense that it is a problem who's roots are midway between an actual disturbance (a perceived sound with an actual source… regardless of its form) and tinnitus, where the brain is amplifying a particular frequency because we are trying to find meaning in it. In a previous post, I mentioned that the best way to deal with the hum is to acknowledge it, but do not give weight to it. This can take some effort, but ultimately, re-training your brain to 'not' hear it may be our best weapon against it. I have personally found that when I do this, I can go for many weeks without hearing it. One of these days I will quit these forums because that too is giving weight to the hum. On 06/12/2012, at 8:21 PM, "john dawes" <[email protected]> wrote: > My last experiment to control the Hum using a mains powered electric fan > ended in failure. I have since tried the following experiment using a simple > square wave generator with a frequency of 1 to 100 cycles per second. The > output was fed into a 3 inch pillow speaker and the amplitude adjusted to be > approximately the same level as the perceived Hum. > > At low frequencies the output from the speaker resembled the ticking of a > clock, the sound was not unpleasant but it did not block the Hum Increasing > the frequency produced some strange effects like the sound of people talking > very softly, and sometimes a hint of music playing. However, the experiment > did not block the Hum or produce a noise conducive to sleep. > > I emphases that these were personal observations and should in no way deter > others from experimenting to control the nocuous Hum > > > -- > 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. -- 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.
