Can you hear me now?

Discussion in 'Chit Chat' started by EqtTrdr, Jun 14, 2006.

  1. so cool....

    "Teens Turn 'Repeller' into Adult-Proof Ringtone

    Listen to this story... by Melissa Block

    All Things Considered, May 26, 2006 · The war between teens and authority figures has a new -- or old -- front: ears. British shopkeepers tired of teenage loiterers have turned to the Mosquito teen repellent, which emits a high-pitch frequency that most teenagers can hear -- but not most adults.

    But now teens have struck back against the Mosquito: They are using the same sound to communicate without adults' knowledge.

    At issue is a text-message ringtone that emits the same pitch as the Mosquito. Using it, students can learn about a new message while they're in class -- where they're not supposed to be using their cellphones. Most of their teachers can't hear the alert.

    Inventor Howard Stapleton, creator of the Mosquito teen repellent, says only a few people over age 30 can hear the Mosquito's sound. He and his 16-year-old daughter Isabel talk to Melissa Block about the sound, which has been dubbed "Teen Buzz.""


    The NY Times published a story on the Mosquito Ringtone this morning. Allegedly inaudible to adults, this 17Khz ringtone has become popular among teens looking to be able to send and receive text messages surreptitiously in class. They even included a sample of the ringtone, so you could determine for yourself whether it’s audible or not. Well, I had no trouble hearing it, and according to the convenient chart provided (reproduced at left), at the age of 42 most people my age can’t hear anything beyond 13Khz. Apparently, I am more youthful than I thought…

    Wondering what I could hear, I took a quick trip to the NCH Swift Sound website, and downloaded the NCH Tone Generator application. This little tool is used by audio engineers to generate various different kinds of tones ranging from square waves to pink noise to sine waves, and a bunch more. I generated a four different sets of tones at 15Khz, 16Khz, 17Khz, and 18Khz and listened to them, comparing them with the mosquito. The mosquito is a very dirty tone, with lots of noise in it. Perhaps that’s because it’s been converted to MP3, or perhaps it’s not a pure sine wave. In any case, while the allegedly 17Khz mosquito tone is quite audible, I had difficulty hearing a true 17Khz sine wave. The 18Khz tone was inaudible.

    You can listen to all four WAV files for yourself and do your own comparison. I recommend not turning the volume way up. Despite the fact that they are nearly inaudible, they are still very high energy sound, and my ears were sore after several listenings.
  3. what happened to the silent vibrating alert??

  4. Ricter


    Just what I was wondering. Another solution looking for a problem. Way to go kids!