 The Clarinet BBoard
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Author: Jason
Date: 2001-06-21 23:43
Maybe this is totally ordinary, and nothing new, but being that I just started playing the bass clarinet, it comes to an awful surprise. When I play in the same room as my computer, if I play certain notes, I can see sine waves on my monitor. It also does this with LCD clocks, a little bit with televisions, and even with a rotary fan. Now granted, I'm not seeing the sine wave graph, I'm just seeing the monitor distort to form an approximate sine wave. I can tell it has to do with the vibrations, since when I play the lower to lowest notes on the bass, the distortions are large and wobbly, but when I start playing into the high register (and when I intentinally sqeak to produce this effect) I see ripples on the screen that correspond with differing sounds waves produced. If anyone has any clear-cut explanations, it'd be great, as well as any comments.
~Jason
P.S. It scared the living daylights out of me when I first saw this happen, and when other people couldn't see the distortions I was talking about (when *I* was playing), I started thinking about whether or not I was hallucinating. Luckily I had a family member play, and alas, I could not see the distortions. So I do believe it has to do with the bass clarinet vibrating a certain frequencies so that they shake the eyes, causing the distortions. But this is merely a hypothesis. I'm very curious as so why it only works with monitors, LCD clocks, etc. Thanks!
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Author: Mark Charette
Date: 2001-06-22 00:27
Your monitor, led/lcd equipment, florescent lamps, etc., all "flash" - the lights at 120 times/sec, the others at possibly different frequencies. When your head vibrates at close the same frequency you get a strobe effect.
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Author: Jason
Date: 2001-06-22 01:56
Sounds like a good enough explanation, I thought about that, but I don't understand, if the monitor "refreshes" or "flashes" at a constant speed, how come I see different distortions?
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Author: Jim
Date: 2001-06-22 04:19
Mark,
Its interesting that he sees a "sine wave" as the 60 Hertz alternating current changes you mention do form a sine wave. Do you remember the old speed check disks for record turntables that used a neon or flourscent lamp as a strobe? Same principle.
I'll have to borrow my son's bass and see if I can duplicate this.
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Author: Mark Charette
Date: 2001-06-22 04:34
Hopefully the monitor is refresing faster than 60Hz - mine's set to 80Hz, and 72Hz is about the lowest I can use and be relatively comfortable ...
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Author: Eoin McAuley
Date: 2001-06-22 07:35
The default refresh rate for monitors is 60Hz. This produces an annoying flicker for me, but many people can't even see it. If you push the refresh frequency up to 70 or 80, it is unnoticeable to almost everybody.
The sine wave effect is caused because your eyeballs are vibrating with a sine wave. When you play the low notes, your whole body vibrates. The monitor produces a flashing light. When the frequency it flashes is close to the frequency your eyes are vibrating, you get these interference effects.
Men don't need a bass clarinet to do this. If you hum very low notes you will get the same effect. Women can't sing low enough in pitch to do this.
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Author: Anji
Date: 2001-06-22 10:48
As you approach one-ness with the cosmos, and tune in to the fundamental frequency of all things, you experience other phenomena as confluation of waves.
Read your Feynman, it posits the same notion.
It could also just be the Flyback on your monitor is loose and rattling on the tube.
What exactly DO you soak your mouthpiece in, anyway?
anji
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Author: Don Poulsen
Date: 2001-06-22 14:09
Jason--
I have often seen this happen when playing low notes on my bass clarinet in front of a computer monitor. And as Eoin says, by just humming a very low note while sitting in front of my monitor here, I see apparent vibrations on the screen.
You see different distortions when you play different notes because the difference between your vibration rate and the refresh rate of your monitor/TV changes as you change notes. Hmmm... if you could set the refresh rate of your monitor to the precise frequency of the note you are trying to play, you could tune your instrument by observing the point at which you no longer see the oscillations!
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Author: Steven
Date: 2001-06-22 16:05
When I played bass in high school, I noticed this same phenomenon when playing while looking at the stobotuner and under certain flourescent lights. It didn't bother me nearly as much as the fact that I had a filling in a tooth that would resonate whenever I played low E flat. In Dello Joio's "From Every Horizon" I had a solo at the opening that ended with a sustained low e flat - by the end of which my eyes would be crossed with the pain. My dentist adjusted the filling later to move it off resonance.
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Author: David Spiegelthal
Date: 2001-06-22 20:21
You can stop rattling your noggin so much if you use a mouthpiece patch. Then maybe you will un-sync from the home electronics...................
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Author: Jason
Date: 2001-06-23 01:38
Thanks for explanations! One more question: does an LCD clock refresh? I didn't ever think about it, but I guess it does, since I can see the same distortions with them. Again, thanks!
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Author: Gordon (NZ)
Date: 2001-06-24 02:36
You may reduce (or increase) this effect by putting higher quality ligatures around your eyeballs. 
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Author: m
Date: 2001-06-26 14:16
sorry for this post everyone I have to get my name off of the your name section bye
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