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Mark Evans

Why Do Ceiling Fans Cause Tremolo In Free Reeds?

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Why do ceiling fans have that tremolo effect on free reed instruments? Even in the stone chapel here with (I'm guessing) 40 feet or better up to the offending fans the tremolo is horrible. No other instrument or the human voice seems to be effected in a similar manner.

 

There are some mighty smart cats prowling this sight and I figure after 25 years of being perplexed and sometimes vexed with this situation I'll ask and be enlightened.

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Why do ceiling fans have that tremolo effect on free reed instruments? ...

 

There are some mighty smart cats prowling this sight and I figure after 25 years of being perplexed and sometimes vexed with this situation I'll ask and be enlightened.

Mark,

 

You are not the first to ask, the topic has already been dicussed, both last year, and in the old forums.

 

Mind you, with our weather we don't experience it here (no call for ceiling fans ... :( ).

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This was also discussed ad nauseum (it really did go on endlessly) once or twice on the squeezebox newsgroup (try deja news to find it). I was vaguely interested at first, but so many windbags and blowhards putting forward various reasons wore me out.

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Or perhaps the number of explanations exceeded Ken's ceiling.

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Sounds like a lot of "hot air" to me!

 

Gerry

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Why do ceiling fans have that tremolo effect on free reed instruments?  Even in the stone chapel here with (I'm guessing) 40 feet or better up to the offending fans the tremolo is horrible.  No other instrument or the human voice seems to be effected in a similar manner.

 

It's not just free reed instruments that are affected by ceiling fans. I had a ceiling fan that beckoned a bat. Imagine the disappointment. Looking for love and finding something so completely unresponsive.

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Okay, so let's ask ourselves: what makes a concertina different from other instruments?

 

One is that the sound projects out the sides of the instrument, and bounces off walls. Could that be the reason fans cause trouble? If so, you should get a similar effect with any other very directional instrument aimed away from you.

 

Caj

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Okay, so let's ask ourselves:  what makes a concertina different from other instruments?

One is that the sound projects out the sides of the instrument, and bounces off walls.

Eh? I haven't heard of this effect depending on the size or shape of the room, nor which way you're facing in the room. I suppose you could test that hypothesis, though, by placing two mandolin players back to back and turned sideways. :)

 

What is different about concertinas is that the reed vibration which generates the sound depends on the difference in air pressure between the inside and outside of the instrument. And the fan blades do cause alternating pressure pulses in the (outside) air. If that's the cause, the presence of the walls shouldn't matter, and you should also get the effect from a fan (presumably not a "ceiling" fan ;)) on an outdoor patio.

 

And if that's the cause, then stringed instruments shouldn't be affected, but concertinas, accordions, and harmonicas would be, and maybe clarinets and oboes, too.

 

But there's also the fact that with rotating fan blades, sound alternates between being reflected off the blades and (between the blades) off the wall behind. If that's the cause, then stringed instruments should also be affected, but the effect should disappear if you move outdoors with your fan and concertina or mandolin.

 

Anybody want to perform those indoor-outdoor tests? I would, but I don't have a fan. (Not much need, here in Denmark.)

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Anybody want to perform those indoor-outdoor tests?  I would, but I don't have a fan.  (Not much need, here in Denmark.)

Likewise here Jim too, but I would be glad to carry out the tests; if somebody would like to pay my air fare to New Orleans ... ;)

Edited by Stephen Chambers

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Anybody want to perform those indoor-outdoor tests?  I would, but I don't have a fan.  (Not much need, here in Denmark.)

Likewise here Jim too, but I would be glad to carry out the tests; if somebody would like to pay my air fair to New Orleans ... ;)

Maybe a university research grant? I once knew a fellow who claimed to have gotten a grant to study the mutation rates of the yeasts that grew under the mats on the bars in German pubs (Kneipen?). He'd have a couple of beers, take a scraping from under the mat, then go to the next pub... and do the same rounds every day. After a few weeks he had enough samples that he could look for changes over time. After half a year he had built up a sufficient statistical sample to demonstrate that measurable evolution was taking place, and he was able to renew the grant for a couple more years in order to track longer-term trends.

 

Nice work if you can get it. :)

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What is different about concertinas is that the reed vibration which generates the sound depends on the difference in air pressure between the inside and outside of the instrument. And the fan blades do cause alternating pressure pulses in the (outside) air. If that's the cause, the presence of the walls shouldn't matter, and you should also get the effect from a fan (presumably not a "ceiling" fan ;)) on an outdoor patio.

 

Well, Jim I like that and should I be asked why I want the fan off at a session will be able to say something besides "I dunno, just makes me box sound...all wonky". Thank you.

 

Now if I could figure out why when I'm on me porch with a medium breeze blowing my penny whistle cranks right along, but if I switch to my low D whistle it's hard to get a note out at all.

 

Your musing not withstanding, Stephen should look into a field study of the ceiling fan effect in New Orleans. One would in fairness have to expand the study sites to certain music clubs close to Lafeyette and a club I know of in Greun, Texas. A field study assistant would be a must. I have had a certain effection for the local brews Dixie and Bach Shiner and would be willing to serve. Perhaps the National Endowment for the Arts could fund such an important study :P .

Edited by Mark Evans

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Now if I could figure out why when I'm on me porch with a medium breeze blowing my penny whistle cranks right along, but if I switch to my low D whistle it's hard to get a note out at all.

Two likely factors:

.. 1) It's a general principle with wind instruments that production of lower notes involves a greater volume of air flow, but less pressure. Wind pressure being constant, it would then have a proportionally greater effect on lower notes.

.. 2) But a smaller windway also tends to work at lower pressure, so if the mouthpiece on your low-D is proportionately narrower than on your high-D, that will have a similar effect. (E.g., my large-windway Copelands -- both high-D and low-D -- are more resistant to such wind effects than my high-D Generation, but the high-D Copeland is more resistant than the low-D.)

.. 3) Not a third factor, but 1+2. Combining the two effects is, of course more effective than either one alone.

 

One way to escape the effect of the wind, by the way, is to turn your back to it. ;)

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