Spraying for Mosquitos Page 2

Free Ringtones!

For you kids out there already bored with your Mosquito test tones, or who don't want to pay for an official Mosquito tone, or who need multiple "inaudible" ringtones to distinguish among callers or types of messages, here are a few of the experimental ringtones I came up with using the same pulse and duration characteristics as the octave-spaced sequence. Each tone comprises four bursts of a frequency followed by slightly less than a second of silence, with the whole burst/silence sequence repeated once (four bursts, silence, four bursts, silence). For those of you who have phones that will take computer-downloads of ringtones, it should be no great bother to install my MP3 ringtones - just follow the normal procedure used for ripped music! You can select among 12-kHz bursts (which should be audible to anyone with normal hearing), bursts at the NTSC line-frequency, bursts in the Mosquito range (17 kHz), and, an acid test for youthful ears, bursts at 19 kHz, which even the freshest of ears will be hard put to hear. (The highest I can remember hearing after I became frequency-range-aware was a little above 18 kHz.) At these highest frequencies the sense of precise pitch disappears - you just hear a high-frequency sonic "presence," not a specific "note" - so if you can hear them at all you may find it hard to tell them apart. For variety, I've also made a ringtone that sweeps up twice from 16.5 to 18.5 kHz, covering the Mosquito frequency range. This should sound quite different from the others. Here's what that sweep sounds like transposed down one octave.

0606_dartboard_400 The "envelope" used for the bursts in my ringtones

Actually, I think it's ridiculous for anybody with computer music-ripping experience to have to pay for a ringtone. While I might have a little more experience than many, it took me only about 45 minutes to cook up all the tones in this article, and much of that time was spent finding and experimenting with an "envelope" for the bursts (the buildup and decay characteristics of the sine wave in each burst) and in looking for a microphone for recording the frequency announcements. I couldn't find a real mike, so I used a large-diaphragm (over-the-ear) dynamic stereo headphone I had lying around and plugged it into the mike input of the laptop I was using to generate and edit the ringtones. The headphones worked adequately as a microphone - it's a trick from the early days of radio - but the frequency response wasn't perfect, so the announcements had to amplified, filtered, and equalized, which also took a few minutes of experimentation.

Anyone who wants to use a specific song as a ringtone, and who has a phone that will accept a direct computer download of a sound file (as my Motorola Razr does for MP3 recordings), can easily make a ringtone from a CD-ripped track (from one of your own, paid-for recordings, right?) using a software cellphone-management program. Such software enables you to turn any digitized audio - music, sound effects, home recordings of voices, or, scary thought, pet vocalizations - into ringtones. Motorola's Phone Tools program for the Razr and other Motorola units works just fine, though I use one of my pro-grade editing systems (Adobe Audition or Sony's Sound Forge) for editing and processing CD tracks to optimize them for ringtone use. (I might go into what this entails a later Dartboard entry.) As for what I'm using for my Razr's ringtones, you can forget 15 kHz, 17 kHz, and Welsh mosquitos, since I've got something with real bite. All my ringtones are carefully selected blasts of opera - absolutely guaranteed clear to loitering teenagers from the immediate vicinity!

Note on the ringtones: While you are free to download my ringtones to use as you please, don't just email them directly to your friends. Instead, send them a link to this page so they can download the tones and read the article. This scores brownie points with my boss and encourages learning about audio and equipment. If your phone cannot cleanly handle these MP3s - my Razr emits noises at much lower frequencies when highest of them start playing - be warned that conversion of these particular MP3s into any other format may destroy their usefulness. Unless you specially adjust their encoding parameters, something that is not always possible, most audio codecs will throw out anything they deem to be inaudible, which could include the very frequencies making these tones adult-proof.

See the previous David's Dartboard entry.

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