09-13-2014, 12:52 PM
Masked tracks need a good frequency response between approximately 1 and 4 kHz. This is the range of most human speech. ALL speakers and headphones do this well, for that exact reason.
Adam, ultrasonics have been tested in noisy environments and found to work surprisingly well. In one experiment, it was tested while music was being played at pretty much maximum volume for the speakers, and results were had in the same way and at the same rate as without, on a tester sitting 12 feet away.
In another series of tests, we had several testers in a larger room, and they were seated between 5 and 40 feet away. With the test track playing at approximately -23 dB at the source (a cell phone) according to FrequenSee, and our best efforts to recreate a club-like level of ambient music volume, we observed responses in all five of the testers. The closer ones responded faster, and the responses came sequentially as the distance increased. It required about 7 minutes to observe the first response in the tester at 5 feet, and about 60 minutes to observe initial response in the one placed 40 feet away.
Since volume of audio drops off at the square of the distance, this is roughly what we were expecting, although to my surprise the testers turned out to be much more affected than I thought they would be.
In other words, ultrasonic audio appears to be able to virtually ignore the effects of other audio because of its pitch, which effectively puts it in an entirely different "channel".
Adam, ultrasonics have been tested in noisy environments and found to work surprisingly well. In one experiment, it was tested while music was being played at pretty much maximum volume for the speakers, and results were had in the same way and at the same rate as without, on a tester sitting 12 feet away.
In another series of tests, we had several testers in a larger room, and they were seated between 5 and 40 feet away. With the test track playing at approximately -23 dB at the source (a cell phone) according to FrequenSee, and our best efforts to recreate a club-like level of ambient music volume, we observed responses in all five of the testers. The closer ones responded faster, and the responses came sequentially as the distance increased. It required about 7 minutes to observe the first response in the tester at 5 feet, and about 60 minutes to observe initial response in the one placed 40 feet away.
Since volume of audio drops off at the square of the distance, this is roughly what we were expecting, although to my surprise the testers turned out to be much more affected than I thought they would be.
In other words, ultrasonic audio appears to be able to virtually ignore the effects of other audio because of its pitch, which effectively puts it in an entirely different "channel".
Subliminal Audio Specialist & Administrator
The scientist has a question to find an answer for. The pseudo-scientist has an answer to find a question for. ~ "Failure is the path of least persistence." - Chinese Fortune Cookie ~ Logic left. Emotion right. But thinking, straight ahead. ~ Sperate supra omnia in valorem. (The value of trust is above all else.) ~ Meowsomeness!
The scientist has a question to find an answer for. The pseudo-scientist has an answer to find a question for. ~ "Failure is the path of least persistence." - Chinese Fortune Cookie ~ Logic left. Emotion right. But thinking, straight ahead. ~ Sperate supra omnia in valorem. (The value of trust is above all else.) ~ Meowsomeness!