More whistles

Caprice · More whistles

I'm normally not so fond of high pitch whistles so I decided to pestering my neighbors( I live in a flat) with a lower pitch one

:

The piping on the boiler is a somewhat improvised, will make a proper whistle valve with a rope or chain to pull. The steam pressure could also be a little higher I guess(and drier - another coil of super heated pipe) to make it sound better.

C.

Edit: The measurements is 10 mm brass pipe plus ~1 inch of 22 mm diameter copper pipe, total height 90 mm.

xlchainsaw

this is very interesting. i like the design i never thought of adding a bigger top. im very curious to know if the the two tone was caused by the valve or wether its the whistle.????? seeing that i need to make 12 for lizs calliope your experiment couldnt have come at a better time for me. thankyou very much.

IndianaRog

Caprice, I love the tone and the ramp up/down as you turn the valve. Different and nice!

whistleman

very nice tone to that!

Caprice

Thanks! Hope my neighbors think the same.

xlchainsaw, Is there two tones? Haven't even thought about that.

I'm just a whistle newbie? This is the first whistle I made so I have nothing to compare with...

If so, I have have no idea why, could be a soldering blob in the "passage" to the whistle opening or something else.

The bigger top(called a Helmholtz resonator) make it possible to have a shorter whistle with a lower pitch:

Here's where I got the idea:

xlchainsaw

thanks for that. i will make one tomorrow

it wont take long and i will put it on a steam valve with a quick on and off to check if its a two tone. it really sounds great. thanks for the link . if its ok with you i will see if i can post a vid under your post for cross reference. i have the materials all set to go and was about to start . to get a low c note the whistle needs to be ten inches long. your method might help reduce this or even!!!!! have a better tone!

Caprice

xlchainsaw, no problem post as much as you like! And thanks for the kind words.

One thing I remember when building it was that moving the bigger pipe up and down on the smaller one didn't lower the tone much but that's perhaps kind of obvious? Finding the balance between the length of both pipes sound-wise could be a little bit tricky I guess.

Looking forward to the result.

xlchainsaw

thanks for that. we have an electronic tuner which identifies the note. its all trial and error.

Les

That looks good and has a very nice tone to it as well.

Caprice

Thanks Les!

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BTW, regarding the "two tone" frequencies discussion above, I should have read my own links better:

robertosala

Nice pitch! I like it a lot!

Rob

igy569

Very Kewl.

Bugsy

I'm looking forward to hearing that one "Live" one day, Caprice.

xlchainsaw

what a fun whistle!! a big thankyou to caprice. as stated i made one today so here it is.

here she blows!!!! operated by a lever valve.

with a spring valve.

a very fun whistle. on air its two tone! how its opened on air also plays different. it also hums and vibrates in the hand!!! but on steam!!!!!!!

btw it blows a low b.

Les

That's very nice, what pressure was that blowing at??

Caprice

Bugsy (and others), thanks!

I'm a little bit of the eremite type but we'll see...

xlchainsaw, that's sounds fantastic!!!
(Is there a difference sound wise between ordinary "willow" type whistles and yours, with a smaller diameter air gap plate?)

My whistle sounds best at 15-20 PSI, higher it goes up in "falsetto"

C.

xlchainsaw

xlchainsaw

Caprice

whistleman

great!!!!!

Caprice

Thanks!, still a long way to go on the (low pitch) whistle road though.

Caprice

I did another (longer)video, this time outdoors(on a chilly day) with lots of (mildly super heated)steam.

The safety valve blows on a little more than 15 Psi.

The burner is the "Japanese type" from this thread:
http://modelsteam.myfreeforum.org...aporizing_burner__about23196.html

mogogear

Sweet whistles there gentlemen....I am in love with that low B...I have the same preference for long tubular wind chimes... the big deep and throaty types are so pleasing...

A bit like Demi Moore's voice.......

Off to the lathe

mogogear

A little more on Helmholtz whistle design( you just have to love having this stuff laying about on the internet

"Whistle Components"

The whistles have three main components. The aperture, bell, and resonator.

Aperture
The aperture is responsible for creating a thin curtain of fluid that impacts the edges of the bell mouth. The aperture assembly produces a circular fluid curtain by allowing the fluid to pass through a narrow gap. The gap dimension is 0.0065 inch. It is critical for good operation of the whistle that the aperture gap be even or symmetrical all around the aperture. The two parts that are used to construct a Bangham whistle aperture assembly for Gauge 1 sized whistles are produced on commercial CNC Swiss lathes to maintain tolerance on the width of the gap when the parts are assembled into an aperture assembly.

Bell

The bell was previously referred to as the resonator tube (SITG #66). Larry has decided that it really functions as the bell on a prototype whistle and should be called such. This portion is the neck section of the Helmholtz Resonator. Either way, the part of the bell that the jet of steam from the aperture strikes is the mouth. After the jet strikes the mouth, the bell can either go straight or have an angle put into it.

The actual realized physical length of the bell is interdependent upon the frequency desired, and the volume of the resonator. This has to be calculated using the Helmholtz formula.

The maximum total length of the bell is ten times the inside diameter (ID) of the bell. This works out to 1.6 inches (40.64 mm) when using the currently standard 0.1875 (3/16) outside diameter, 0.014 wall, .159 inside diameter Brass tubing. This length is inclusive of any bends, and parts inserted into the resonator cavity. The minimum length is usually dependent upon mechanical mounting concerns for attaching the aperture assembly to the bell.

Resonator

The magic thing that makes it work. Actually, it's proper name including the bell is "Helmholtz Resonator". Stick that in Google and have fun.

The resonator can take many shapes, normally sticking with tubular and rectangular sections since they are easier to fabricate. The resonator also has been made in "C" shapes for inclusion in dome style whistles.
Tuning or Sizing the Bell and Resonator

The Helmholtz resonator formula determines the sizing of the bell and resonator. The formula requires the inside diameter of the neck, the neck length, and the resonator volume. I found that creating a Microsoft Excel sheet and utilizing the solver function was the easiest way to get the dimensioning of the various parts. Also, it is easier to let the computer figure out a square root.
Helmholtz Formula by Larry Bangham in SITG #67 rephrased

freq = K * SQRT( (Aperture Area / Resonator Volume ) * ( Bell length + (( .96 * Aperture Area) / 2)) ) )

Where K = Speed of sound in air / 2pi = 2156 for air

Caprice

Thanks mogogear

, I like that low pitch also, at the end of the video you can hear it "choke" in falsetto though, when I open the valve to much.
I will make a lever as xlchainsaw did on his(which sounds much better than mine IMO.) to remedy this.
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I read that Helmholtz text also, after I was finished (Don't remember where though). Thanks for posting it here! On the next whistle I build think I will try and follow some of that instead of doing it the Laurel and Hardy way.

Gap dimensions of 0.0065" could be hard to achieve without a lathe though...