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acoustics101
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Mon Sep 08, 2008 7:37 pm

The sounds of the pipes I designed should open from this link. Since the sampling on this site is limited to 11.025 kHz, a number of the upper harmonics of my Gamba pipe (rwgmb) are missing, limiting the frequency response to about 5 kHz and dulling the sound to that of AM radio.
http://www.fonema.se/pipref/pipref.htm

If you want a full 44.1 kHz sample out to a frequency response of 20 kHz, send me a private message.

John in MA wrote:Those sound samples aren't downloading for me.
The most overlooked opportunities are in the learning of and improvement in old technologies.

Richard Weisenberger

Jim_Ferer
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Mon Sep 08, 2008 8:25 pm

Google Convert says 1 pound per square inch = 2.03625437 inches of mercury.

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acoustics101
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Mon Sep 08, 2008 8:42 pm

Wind pressures in pipe organs are measured in inches of water, not mercury. There's a huge difference!

Jim_Ferer wrote:Google Convert says 1 pound per square inch = 2.03625437 inches of mercury.
The most overlooked opportunities are in the learning of and improvement in old technologies.

Richard Weisenberger

Robert Gift
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Tue Sep 09, 2008 12:40 am

1 psi = 27.6 water column inches.
I remembered incorrectly 26.6.

A typical 3-1/2 inch pipe organ pressure = .126 psi

In this photo it appears the far right siren sounded less because there is less wear from the pneumatic actuator rubbing on the stator cover.
Image

I assume they all ran the same RPM conected by the belt to a motor.
This means that some notes will be out of tune because some stators cannot have the precise number of ports necessary for them to be in proper tune since they are on one common RPM.
This was/is the same problem with the Hammond tone wheels.

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Daniel
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Tue Sep 09, 2008 1:43 am

I suppose the only way to get precise pitches is to use different size pulleys off the main drive belt.
Lex orandi, lex credendi, lex vivendi.

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acoustics101
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Tue Sep 09, 2008 1:17 pm

At the time I first heard about it during the 1980s, the analogy given for the choppers was that of the tone wheels on a Hammond organ.

Robert Gift wrote:I assume they all ran the same RPM conected by the belt to a motor.
This means that some notes will be out of tune because some stators cannot have the precise number of ports necessary for them to be in proper tune since they are on one common RPM.
This was/is the same problem with the Hammond tone wheels.
The most overlooked opportunities are in the learning of and improvement in old technologies.

Richard Weisenberger

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SirenMadness
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Sat Sep 20, 2008 3:25 am

Simply amazing! You can really notice the choppy, siren-like quality in the sound! Yes, the only reasonable explanation to the rapid change in pitch is an inner moving stator. It looks like those stator-movers are hydraulically operated; they each look like they receive hydraulic pressure at the same time, only having a valve within themselves actuate them.
~ Peter Radanovic

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John in MA
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Sun Sep 21, 2008 12:22 am

It's a pneumatic control system. You can see the FRL down at the bottom right. You're right about the actuation. The black boxes on top of the sirens look like solenoid valves, with the plumbing going to the cylinders.

Robert Gift
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Sun Sep 21, 2008 3:33 am

John in MA wrote:It's a pneumatic control system. You can see the FRL down at the bottom right. You're right about the actuation. The black boxes on top of the sirens look like solenoid valves, with the plumbing going to the cylinders.
What is "FRL"?

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FahmiRBLX
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Re: Musical Siren in Japan (includes sound file)

Thu Dec 21, 2017 9:04 am

Something. I can't get into the URL going into the Musical Siren's .wma file. Anybody can upload into a YouTube form?
A Muslim Malaysian, a siren & aviation enthusiast, and gamer.

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