produce 18-19 Hz tone

[[email protected]]

I'm interested in conducting some infrasound experiments using an 18-19
Hz tone. At first I was looking for speakers. But components in that
acoustical range are quite expensive. And since I'm only interested in
a 1 Hz range alternate methods will suffice. I'm allocating $200-300
for this experiment. Any ideas?

[Don Pearce]

On 1 Sep 2006 10:35:03 -0700, wrote:

>I'm interested in conducting some infrasound experiments using an 18-19
>Hz tone. At first I was looking for speakers. But components in that
>acoustical range are quite expensive. And since I'm only interested in
>a 1 Hz range alternate methods will suffice. I'm allocating $200-300
>for this experiment. Any ideas?

Use a motor and speed controller and a crank linked to a piston.

d

--
Pearce Consulting
http://www.pearce.uk.com

[RD Jones]

wrote:

> I'm interested in conducting some infrasound experiments using an 18-19
> Hz tone. At first I was looking for speakers. But components in that
> acoustical range are quite expensive. And since I'm only interested in
> a 1 Hz range alternate methods will suffice. I'm allocating $200-300
> for this experiment. Any ideas?

What kind of levels do you need to reproduce ?

A transmission line should be able to be constructed
cheaply that will go down to this freq range and the
most expensive component will be the woofer.
MCM/Parts Express has some woofers with FAR
in this range.

rd

[philicorda]

On Fri, 01 Sep 2006 10:35:03 -0700, sky_diver_ wrote:

> I'm interested in conducting some infrasound experiments using an 18-19 Hz
> tone. At first I was looking for speakers. But components in that
> acoustical range are quite expensive. And since I'm only interested in a 1
> Hz range alternate methods will suffice. I'm allocating $200-300 for this
> experiment. Any ideas?

Get a long piece of large diameter plastic sewer pipe tuned to the
frequency you want to make.
Put a speaker at one end.

It'll only make one note, but will be very efficient.

[GregS]

In article >, philicorda > wrote:
>On Fri, 01 Sep 2006 10:35:03 -0700, sky_diver_ wrote:
>
>> I'm interested in conducting some infrasound experiments using an 18-19 Hz
>> tone. At first I was looking for speakers. But components in that
>> acoustical range are quite expensive. And since I'm only interested in a 1
>> Hz range alternate methods will suffice. I'm allocating $200-300 for this
>> experiment. Any ideas?
>
>Get a long piece of large diameter plastic sewer pipe tuned to the
>frequency you want to make.
>Put a speaker at one end.
>
>It'll only make one note, but will be very efficient.

The amount of SPL you need is the main determanant.
I would think about using a bandpass box, because you can determine
the frequency range by altering box size and vent length. Should be no problem
getting by with less than $200.

greg

[Scott Dorsey]

> wrote:
>I'm interested in conducting some infrasound experiments using an 18-19
>Hz tone. At first I was looking for speakers. But components in that
>acoustical range are quite expensive. And since I'm only interested in
>a 1 Hz range alternate methods will suffice. I'm allocating $200-300
>for this experiment. Any ideas?


Build an organ pipe out of 6-inch PVC drainpipe.
The Scientific American book "Physics of Music" has an article on how
organ pipes work, but you can probably find all you need with google.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Carey Carlan]

(Scott Dorsey) wrote in news:eda1gt$sfl$1
@panix2.panix.com:

> > wrote:
>>I'm interested in conducting some infrasound experiments using an 18-19
>>Hz tone. At first I was looking for speakers. But components in that
>>acoustical range are quite expensive. And since I'm only interested in
>>a 1 Hz range alternate methods will suffice. I'm allocating $200-300
>>for this experiment. Any ideas?
>
>
> Build an organ pipe out of 6-inch PVC drainpipe.
> The Scientific American book "Physics of Music" has an article on how
> organ pipes work, but you can probably find all you need with google.
> --scott

About a 29 foot tube, sealed at one end, air flow of 4-5 inches of mercury
(about 2-3 psi) flowing through the tube.

[Dirk Bruere at NeoPax]

Carey Carlan wrote:
> (Scott Dorsey) wrote in news:eda1gt$sfl$1
> @panix2.panix.com:
>
>> > wrote:
>>> I'm interested in conducting some infrasound experiments using an 18-19
>>> Hz tone. At first I was looking for speakers. But components in that
>>> acoustical range are quite expensive. And since I'm only interested in
>>> a 1 Hz range alternate methods will suffice. I'm allocating $200-300
>>> for this experiment. Any ideas?
>>
>> Build an organ pipe out of 6-inch PVC drainpipe.
>> The Scientific American book "Physics of Music" has an article on how
>> organ pipes work, but you can probably find all you need with google.
>> --scott
>
> About a 29 foot tube, sealed at one end, air flow of 4-5 inches of mercury
> (about 2-3 psi) flowing through the tube.

I assume the tube can be folded.

--
Dirk

http://www.onetribe.me.uk/ - The UK's only occult talk show
Presented by Dirk Bruere and Marc Power on ResonanceFM

[Richard Crowley]

"Dirk Bruere at NeoPax" wrote ...
> I assume the tube can be folded.

Yes. It is called "mitering' when they do it to organ
pipes (to make them fit in the chambers). It is done
for both round metal and square wooden pipes.
Typically a 90-degree turn, but folded back over
on themselves is not unheard of.

[Scott Dorsey]

Dirk Bruere at NeoPax > wrote:
>Carey Carlan wrote:
>> (Scott Dorsey) wrote in news:eda1gt$sfl$1
>> @panix2.panix.com:
>>
>>> > wrote:
>>>> I'm interested in conducting some infrasound experiments using an 18-19
>>>> Hz tone. At first I was looking for speakers. But components in that
>>>> acoustical range are quite expensive. And since I'm only interested in
>>>> a 1 Hz range alternate methods will suffice. I'm allocating $200-300
>>>> for this experiment. Any ideas?
>>>
>>> Build an organ pipe out of 6-inch PVC drainpipe.
>>> The Scientific American book "Physics of Music" has an article on how
>>> organ pipes work, but you can probably find all you need with google.
>>
>> About a 29 foot tube, sealed at one end, air flow of 4-5 inches of mercury
>> (about 2-3 psi) flowing through the tube.
>
>I assume the tube can be folded.

It can be, but 6-inch PVC elbows cost substantially more than straight
pipe. But there's no reason you couldn't even make the thing into a 5x5 foot
or so square grid if you had enough elbows.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Adrian Tuddenham]

Carey Carlan > wrote:

> (Scott Dorsey) wrote in news:eda1gt$sfl$1
> @panix2.panix.com:
>
> > > wrote:
> >>I'm interested in conducting some infrasound experiments using an 18-19
> >>Hz tone. At first I was looking for speakers. But components in that
> >>acoustical range are quite expensive. And since I'm only interested in
> >>a 1 Hz range alternate methods will suffice. I'm allocating $200-300
> >>for this experiment. Any ideas?
> >
> >
> > Build an organ pipe out of 6-inch PVC drainpipe.
> > The Scientific American book "Physics of Music" has an article on how
> > organ pipes work, but you can probably find all you need with google.
> > --scott
>
> About a 29 foot tube, sealed at one end, air flow of 4-5 inches of mercury
> (about 2-3 psi) flowing through the tube.

I don't follow that terminology.

Pressure isn't a measure of the rate of flow and a pressure of 2 psi at
one end of a 6" diameter open pipe is going to give a huge flow rate and
need a powerful and expensive blower to maintain it.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Adrian Tuddenham]

Richard Crowley > wrote:

> "Dirk Bruere at NeoPax" wrote ...
> > I assume the tube can be folded.
>
> Yes. It is called "mitering' when they do it to organ
> pipes (to make them fit in the chambers). It is done
> for both round metal and square wooden pipes.
> Typically a 90-degree turn, but folded back over
> on themselves is not unheard of.

Most organs seem to make up the 90 degrees from two 45-degree mitres
fairly close together. A single 90-degree mitre is likely to cause too
much reflection.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Scott Dorsey]

Adrian Tuddenham > wrote:
>Richard Crowley > wrote:
>
>> "Dirk Bruere at NeoPax" wrote ...
>> > I assume the tube can be folded.
>>
>> Yes. It is called "mitering' when they do it to organ
>> pipes (to make them fit in the chambers). It is done
>> for both round metal and square wooden pipes.
>> Typically a 90-degree turn, but folded back over
>> on themselves is not unheard of.
>
>Most organs seem to make up the 90 degrees from two 45-degree mitres
>fairly close together. A single 90-degree mitre is likely to cause too
>much reflection.

Also, every time you turn a corner, there's considerable resistance to
flow. You get more sound with a given head of air using a straight tube.
But sometimes there's no room foir a straight tube.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Powell]

> wrote

> I'm interested in conducting some infrasound
> experiments using an 18-19 Hz tone. At first I
> was looking for speakers. But components in
> that acoustical range are quite expensive. And
> since I'm only interested in a 1 Hz range alternate
> methods will suffice. I'm allocating $200-300
> for this experiment. Any ideas?
>
You might check out mechanical traducers used
in home theater. These devices attach to furniture
and are powered off a power amp. I've seen them
discounted well within you price range and desired
frequency range.

[Carey Carlan]

(Adrian Tuddenham) wrote in
alid.invalid:

>> About a 29 foot tube, sealed at one end, air flow of 4-5 inches of
>> mercury (about 2-3 psi) flowing through the tube.
>
> I don't follow that terminology.
>
> Pressure isn't a measure of the rate of flow and a pressure of 2 psi
> at one end of a 6" diameter open pipe is going to give a huge flow
> rate and need a powerful and expensive blower to maintain it.

I'm not an organ builder, so you're getting this second hand.

It isn't a flow rate, it's a back pressure. The other end of the pipe is
sealed. Think of it as blowing across the top of a Coke bottle. The
pressure inside will rise to about 2-3 psi to get a proper note. Below
that and the note won't sound, greater pressure yields more volume until
turbulence drives the pipe into harmonics (higher pitches).

[Adrian Tuddenham]

Carey Carlan > wrote:

> (Adrian Tuddenham) wrote in
> alid.invalid:
>
> >> About a 29 foot tube, sealed at one end, air flow of 4-5 inches of
> >> mercury (about 2-3 psi) flowing through the tube.
> >
> > I don't follow that terminology.
> >
> > Pressure isn't a measure of the rate of flow and a pressure of 2 psi
> > at one end of a 6" diameter open pipe is going to give a huge flow
> > rate and need a powerful and expensive blower to maintain it.
>
> I'm not an organ builder, so you're getting this second hand.
>
> It isn't a flow rate, it's a back pressure. The other end of the pipe is
> sealed.

Some pipes are sealed, others are open. An organ usually contains
several ranks of each type because they give different strengths of
harmonics and consequently different tones. For a given length of pipe,
the closed end gives a note approximately an octave lower than an open
end.

> Think of it as blowing across the top of a Coke bottle. The
> pressure inside will rise to about 2-3 psi to get a proper note. Below
> that and the note won't sound, greater pressure yields more volume until
> turbulence drives the pipe into harmonics (higher pitches).

I imagined the reference might have been to the blowing pressure of an
organ pipe; but pressure units were being used to describe flow rate,
which made a nonsense of whatever point the contributor was trying to
convey.

[By the way, organ pipes don't sound in quite the same way as blowing
across bottles: either the air strikes an edge to give the tone or it
vibrates a reed]

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[Carey Carlan]

(Adrian Tuddenham) wrote in
alid.invalid:

> Some pipes are sealed, others are open. An organ usually contains
> several ranks of each type because they give different strengths of
> harmonics and consequently different tones. For a given length of
> pipe, the closed end gives a note approximately an octave lower than
> an open end.

The OP was requesting an 18 Hz tone. That requires a 29 foot closed pipe
or a 58 foot open pipe. I assumed he'd want the closed version.

>> Think of it as blowing across the top of a Coke bottle. The
>> pressure inside will rise to about 2-3 psi to get a proper note.
>> Below that and the note won't sound, greater pressure yields more
>> volume until turbulence drives the pipe into harmonics (higher
>> pitches).
>
> I imagined the reference might have been to the blowing pressure of an
> organ pipe; but pressure units were being used to describe flow rate,
> which made a nonsense of whatever point the contributor was trying to
> convey.
>
> [By the way, organ pipes don't sound in quite the same way as blowing
> across bottles: either the air strikes an edge to give the tone or it
> vibrates a reed]

Back on topic. We're not creating an organ pipe. We're attempting to
create an 18 Hz tone with minimal expense and effort. Building a proper
pipe and wind chest is not in the budget.

[Scott Dorsey]

Carey Carlan > wrote:
>
>Back on topic. We're not creating an organ pipe. We're attempting to
>create an 18 Hz tone with minimal expense and effort. Building a proper
>pipe and wind chest is not in the budget.

Some PVC pipe lifted from a construction site and a shop vac are beyond
the budget?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Carey Carlan]

(Scott Dorsey) wrote in news:edl1ef$690$1
@panix2.panix.com:

>>Back on topic. We're not creating an organ pipe. We're attempting to
>>create an 18 Hz tone with minimal expense and effort. Building a proper
>>pipe and wind chest is not in the budget.
>
> Some PVC pipe lifted from a construction site and a shop vac are beyond
> the budget?

I would expect they are, but the difficult part is making the aperture of a
proper pipe. I found a page that shows the innards of a pipe in action:

http://www.danishchurch.vancouver.bc.ca/history/organ.html

This is do-able, but blowing air across the tip would give you about 50%
efficiency at 5% of the effort.

[Dirk Bruere at NeoPax]

Carey Carlan wrote:
> (Scott Dorsey) wrote in news:edl1ef$690$1
> @panix2.panix.com:
>
>>> Back on topic. We're not creating an organ pipe. We're attempting to
>>> create an 18 Hz tone with minimal expense and effort. Building a proper
>>> pipe and wind chest is not in the budget.
>> Some PVC pipe lifted from a construction site and a shop vac are beyond
>> the budget?
>
> I would expect they are, but the difficult part is making the aperture of a
> proper pipe. I found a page that shows the innards of a pipe in action:
>
> http://www.danishchurch.vancouver.bc.ca/history/organ.html
>
> This is do-able, but blowing air across the tip would give you about 50%
> efficiency at 5% of the effort.

I rather like the mechanical piston approach.

--
Dirk

http://www.onetribe.me.uk/ - The UK's only occult talk show
Presented by Dirk Bruere and Marc Power on ResonanceFM

[Scott Dorsey]

Dirk Bruere at NeoPax > wrote:
>Carey Carlan wrote:
>> (Scott Dorsey) wrote in news:edl1ef$690$1
>> @panix2.panix.com:
>>
>>>> Back on topic. We're not creating an organ pipe. We're attempting to
>>>> create an 18 Hz tone with minimal expense and effort. Building a proper
>>>> pipe and wind chest is not in the budget.
>>> Some PVC pipe lifted from a construction site and a shop vac are beyond
>>> the budget?
>>
>> I would expect they are, but the difficult part is making the aperture of a
>> proper pipe. I found a page that shows the innards of a pipe in action:
>>
>> http://www.danishchurch.vancouver.bc.ca/history/organ.html
>>
>> This is do-able, but blowing air across the tip would give you about 50%
>> efficiency at 5% of the effort.
>
>I rather like the mechanical piston approach.

The piston works REALLY well if you need a very precise amplitude, and
you need constant amplitude over a range of frequencies. The problem is
that you can't move much air with it at all, so it's a great choice if
you need signal in a very small area (like for microphone calibration),
but not so good for sonic boom simulation. Model airplane engines are
a good starting point for a homebrew pistonphone.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

Thank you all.

philicorda wrote:
>Get a long piece of large diameter plastic
>sewer pipe tuned to the frequency you want
>to make. Put a speaker at one end.

For the speaker part, what specifications are required?
What is the concept here? Does the long tube bring out the undertones?

GregS wrote:
>The amount of SPL you need is the main determanant.
>I would think about using a bandpass box, because you
>can determine the frequency range by altering box size
>and vent length. Should be no problem getting by with
>less than $200.

This sounds do-able. How does the volume of the box relate to
the frequency? This method sounds like it also requires a
speaker.

[Dirk Bruere at NeoPax]

Scott Dorsey wrote:
> Dirk Bruere at NeoPax > wrote:
>> Carey Carlan wrote:
>>> (Scott Dorsey) wrote in news:edl1ef$690$1
>>> @panix2.panix.com:
>>>
>>>>> Back on topic. We're not creating an organ pipe. We're attempting to
>>>>> create an 18 Hz tone with minimal expense and effort. Building a proper
>>>>> pipe and wind chest is not in the budget.
>>>> Some PVC pipe lifted from a construction site and a shop vac are beyond
>>>> the budget?
>>> I would expect they are, but the difficult part is making the aperture of a
>>> proper pipe. I found a page that shows the innards of a pipe in action:
>>>
>>> http://www.danishchurch.vancouver.bc.ca/history/organ.html
>>>
>>> This is do-able, but blowing air across the tip would give you about 50%
>>> efficiency at 5% of the effort.
>> I rather like the mechanical piston approach.
>
> The piston works REALLY well if you need a very precise amplitude, and
> you need constant amplitude over a range of frequencies. The problem is
> that you can't move much air with it at all, so it's a great choice if
> you need signal in a very small area (like for microphone calibration),
> but not so good for sonic boom simulation. Model airplane engines are
> a good starting point for a homebrew pistonphone.
> --scott

I was thinking more of something like this:

http://www.soundimage.dk/Different-col/LinearMotor.htm

or this

http://neurosis.mit.edu/mjolnir/

--
Dirk

http://www.onetribe.me.uk/ - The UK's only occult talk show
Presented by Dirk Bruere and Marc Power on ResonanceFM