Tuning with beats and ceiling fans

Marc Weller · Post by **Marc Weller** » 20 May 2003 9:55 am

I'm a newbie pedal steel guitarist (6 mos.) and a veteran six stringer (40 years) and I like tuning with beats. I was having a heck of a time tuning my steel (Williams 400 series D10 through a '70 Fender Super Reverb)as I could never get the beats to completely disappear. I eventually realized that I had beats with individual strings so I concluded there was a problem with the vibrato circuit on my amp. Dragged out a non-vibrato amp, still there. Eliminated the volume pedal, no change. Finally I looked above my head and noticed a big AC motor with a propellor spinning at about 500 RPM. That fan has been there for the past 15 years and is usually on so I guess I just forgot about it !! Turned off the fan and my guitar sounds great. Really glad I didn't have my amp serviced !!

Jon Light · Post by **Jon Light** » 20 May 2003 11:04 am

That's funny. But just out of curiosity, was the problem electrical or acoustic---the moving blades serving as moving baffles?

Marc Weller · Post by **Marc Weller** » 20 May 2003 11:07 am

Electrical, and it continues after I had shut off the switch until the blades had stopped moving.

Jon Light · Post by **Jon Light** » 20 May 2003 11:16 am

Well wait-----doesn't that indicate that it's the sound reflections coming off the moving blades?

Marc Weller · Post by **Marc Weller** » 20 May 2003 11:29 am

I don't think so Jon. The amp is 15 feet away from the fan and four feet from my ear. I suspect that the freewheeling armature continues to have some electrical effect and that's why I continue to hear the ocillation until the fan is motionless.

Jon Light · Post by **Jon Light** » 20 May 2003 11:35 am

ok---here's what I want you to do---get up on a ladder and remove all of the flat blade parts of the ceiling fan. Then turn it back on and report back. I'll be sipping a gin and tonic here while I wait.

alternate plan--you skip the fan dismantling and I'll skip the g & t and get back to my practicing.

Marc Weller · Post by **Marc Weller** » 20 May 2003 2:05 pm

You should lay off those Gin and Tonics if you are serious about practicing. If you are serious about drinking, you should stay away from that steel. I'm gonna fix myself a double Manhattan and head out to the porch. No ceiling fans out there.

Stephen Gambrell · Post by **Stephen Gambrell** » 20 May 2003 2:08 pm

Congratulations! You just came up with the world's biggest Leslie!

Post by **Joey Ace** » 20 May 2003 2:14 pm

I've witnessed this problem in Al Brisco's showroom.

We've learned: The ceiling fan goes off before the tuning starts.

It's not electrical. The waves of air made by the fan counteract with the waves of air the amplifer's speaker makes. Purely a physical thing.

Emmett Roch · Post by **Emmett Roch** » 20 May 2003 2:28 pm

I've had a similar experience. During hot weather I carry a small electric fan to gigs, since the air conditioning in most Texas beer joints never reaches the stage. On one such occasion, we returned to the stage after a break, and when we started playing again my steel had this Leslie-like effect. I looked back at my amp and noticed that somehow my fan had gotten turned around to where it was blowing almost directly into the speaker...I still don't know if a band member accidentally kicked it while leaving the stage...maybe one of them placed it there in an attempt to improve my sound...

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GFI S-12 extended E9

Donny Hinson · Post by **Donny Hinson** » 20 May 2003 2:39 pm

I assure you Marc, the effect you noticed was purely "acoustic reflection", and the only part that electricity played was in moving the fan blades, which reflected the sound.

Jim West · Post by **Jim West** » 20 May 2003 2:57 pm

The fan creates what is known as the "doppler" effect. It is the same thing that raises the pitch of the train horn as the train approaches and lowers the pitch as it goes past. Some of you smarter types can probably do a better job at describing the actual phenomena that takes places during these events. It has to do with the compression of sound waves as the sound producing object moves towards you and the stretching out of the sound waves as the object speeds away from you. Sound waves closer together (compressed) have a higher pitch and sound waves further apart (stretched) have a lower pitch.

It is the doppler effect that makes the Leslie speaker sound the way it does. As the baffle moves towards your ear the pitch is higher (compressed sound waves) as the baffle moves away the pitch is lower (stretched sound waves). This is true vibrato (pitch variation) and not tremolo (amplitude variation).

Bottom line is that you can't tune an instrument with the ceiling fan in motion.[This message was edited by Jim West on 20 May 2003 at 04:07 PM.]

Marc Weller · Post by **Marc Weller** » 20 May 2003 6:02 pm

You guys are sharp. I got my Polytone which has a headphone jack, cranked up the fan and,you guessed it, no more Leslie !!

Terry Downs · Post by **Terry Downs** » 20 May 2003 6:55 pm

Yes it is definitely acoustic, and a thing we have tried to avoid for years. A fan creates air disturbances just like a speaker does. When combined with audio you can hear the flutter.

Regards,
Terry Downs

J D Sauser · Post by **J D Sauser** » 22 May 2003 7:43 am

It's NOT electrical... it's the blades chopping the sound. I could tell you exactly the same stroy, almost word for word, only that the fan had not been there for 15 years. I installed the stupid thing myself!

... J-D

Gene Jones · Post by **Gene Jones** » 22 May 2003 8:35 am

I just turned off the ceiling fan in my music room!

Gene
www.genejones.com

Michael Brebes · Post by **Michael Brebes** » 22 May 2003 8:49 am

It takes time for the sound waves to travel to your ears. The sound bouncing off the fan blades is a shorter distance than the sound bouncing off the ceiling above it. The sound from the ceiling is delayed, making it out of phase with the sound off the fan blades. Because the blades are moving, the difference in timing is constantly changing at the speed of the fan. A simple acoustic phase shifter.

Jim Bob Sedgwick · Post by **Jim Bob Sedgwick** » 22 May 2003 12:32 pm

Hey, a thought ( how rare

) Aren't electric fans cheaper that Leslie speakers?
Does a 15 inch, 18inch, or 12 inch fan sound better. Should the fan be on low, high, or medium speed, and how far should the fan be from the speaker, and at what angle, in perfect degrees?

David L. Donald · Post by **David L. Donald** » 23 May 2003 4:51 am

It is an acoutic phenonmina, but I don't think it's necessarily the fan blades having sound bounce off them.

The medium the sound moves through is air and if the air is still, the sound moves at a constant rate.
But as in the doppler effect if you change the speed of the air..
or the speed and direction of the sound source,
you also change the speed that the vibrations in it travel.

Like a plane flying into a head wind and then turing 180 degrees with the same throttle setting.

So if you have a fan alternately changing the air speed it will effect the vibrational travel speed ; faster and or slower.

I actually recorded something a few decades back using this. We had a kid with a hand cranked fan aimed across the speaker and recorded the sound like that. Subtle but cool.
[This message was edited by David L. Donald on 23 May 2003 at 05:57 AM.]

Lee Baucum · Post by **Lee Baucum** » 23 May 2003 5:05 am

Jim Bob - I believe a 15 inch, all-push (no push/pull) fan will quickly become the industry standard.

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Lee, from South Texas
Down On The Rio Grande

Emmett Roch · Post by **Emmett Roch** » 23 May 2003 1:10 pm

Hey Jim Bob, if we put it in a box and cover it with black tolex, we could call it the DopplerTone.

If you play a single neck guitar, I think a DopplerTone with two 12" fans would work just as good as one with a 15" fan.

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GFI S-12 extended E9

David L. Donald · Post by **David L. Donald** » 24 May 2003 3:06 am

I think the "universal 12" fan is the right choice.
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Also a very light sympathetic fan right in front of the cone, powered by the sound preasure alone, could give an interesting sound for the Dopplertone amp.
It would spin differently for different notes power/volume, with a bit of lag time..
c'est fou!

Jon Light · Post by **Jon Light** » 24 May 2003 5:09 am

A fan with a blade doesn't quite have the appeal of a fan throwing panties.

Jim West · Post by **Jim West** » 24 May 2003 6:30 am

Here's somebody else who has a problem with ceiling fans -
http://people.pinpoint.com/~dimarco/Kitty-1.avi