William Grill had a problem with noise distraction at home. Over the summer, vacationing visitors provided a wealth of noise that needed to be dampened. To solve the problem, Grill added some noise of his own -- continuous static noise to drown out the distraction.
His small, inexpensive random noise generator produces digital noise, which has the advantages of being easily repeatable, free of calibration, and inexpensive to produce. This offering runs on batteries and can be used with headphones as a noise mask to eliminate the sounds of rowdy gamers, crying babies, and gossiping grandmas.
I would suggest that adding more noise to mask other noise may indeed be able to do that, BUT there is a problem in that thye ambient noise level increases. That in turn makes any desired communication more difficult.
A local tavern has installed a system that raises the abient noise level to that of a large bar on a crowded Saturday night, which means that quiet conversation in a booth is not possible. So I will not go there again, and I hope that they go broke, possibly they would learn that such tricks are dumb. It is one thing to attempt to giv the impression that "everybody is here", but it does not work for a lot of people.
@zeeglen: Good point but I feel its good to try out all that is available so at least we can figure out the issues behind them and start addressing them. Who knows the output can be THE one in the future.
Reminds me of a sine wave generator using a complicated counter/prom/DAC instead of a simple Wien Bridge oscillator. Really, is this any better than a back-biased zener (white noise genertor) and audio amplifier?
I used the same technique that Mr. Grill did to generate pseudo-random numbers for a PIC program I wrote once. I copied a random noise generator off the web, like Mr. Grill did and like him, I wrote software code to emulate the function of the hardware. The main program would just look at the number in one of the registers to get a "random" number. I only needed an 8-bit random number, but 16 bits would have been available, had I implemented all 16 bits. There is probably no limit to how many bits you can do with this technique.
Great job, William. Comments in your code would be helpful, however.
When I was in the Mormon Church many years ago, there was white noise piped to speakers in the hallway, so that one could not listen in on conversations in the classrooms or offices. One day lightning damaged the sound system. The amplifier system was in a closet and consisted of several 100W power amplifier modules, a white noise generator, preamplifier and power supply. The sanctuary volume was remotely controlled from the stage. The power amplifier that powered the sanctuary speakers was damaged by lightning, and I temporarily replaced it with the masking system amplifier which was identical to it, but set to a much lower level. I repaired the power amplifier and being identical to the others, I plugged it into the masking amplifier slot. I forgot to turn the gain down and when I turned the system on, it sounded like the space shuttle was being launched from our church hallway.
Until called upon to repair the sound system, I just thought that the soft rushing sound I heard in the hallway was the air conditioning. Until then, I had never even heard of a masking system.
I also find noise iritating, especially when it is added to mask other sounds.
The most offensive noise, though, has been added to a local food establishment to simulate the sounds of a crowd having a good time. My meal companions had not noticed it until I pointed out that none of the other patrons were being that noisey, and as they looked around they realized that it was true, others were quietly talking in their own booths, while the ambient din was much louder than that. This is especially bothersome to me because I have damaged hearing, and the increase in ambient noise tends to make having a conversation difficult.
But even worse than that is the background "music" played in both offices and some stores. This is never the good quality stuff, but rather the stuff that is available much cheaper because nobody liked it. ( I am referring to the copyright fees). That garbage, played through paging trumpet speakers, is quite offensive to my ears.
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