Contrabass Digest

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2002-01-08

 
Date: Mon, 07 Jan 2002 16:35:48 -0700
From: "David F."
Subject: Re: [CB] [CB Digest]

Now what do we use as a sounding devise?
Sadly, I've heard the low guttural resonance of a flue pipe fire aprox.
23 ft long, I can only imagine the sound this thing would put out.

David F
 

"> According to
> http://school.discovery.com/homeworkhelp/worldbook/atozgeography/s/537
> 980.html, the actual height is 1250 feet, resulting in a frequency of
> 0.4096, still about Ab-6, assuming standard temperature and pressure.
> An extra 12 feet of length would bring it into tune, or we could lop
> off the top 58 feet, and bring it up to A concert...  ;-)  I wonder
> if this is within the hearing ranges of elephants or whales?

---------------------------------------------------------

Date: Mon, 7 Jan 2002 16:36:29 -0800
From: Grant Green
Subject: Re: [CB] Sudbury and rosin
 

>Maybe not, though.  In high school, I met a young violin student diagnosed
>with hysterical blindness.  He turned out not to be hysterical at all:  From
>diligent practicing and constant exposure, he had developed a violent
>sensitivity to the rosin he used on his bow.

My wife comes from a family of violin-makers, one of whom told us
that around the turn of the century (the previous century), it was
not uncommon for pit orchestra musicians to expire from respiratory
ailments caused by inhaling the rosin that rained down on them from
the stage over the years.  It used to be common practice to dust the
stage with rosin so that the dancers (and actors?) wouldn't slide.
Apparently intensely irritating to inhale...

Grant

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Green
Sarrusophones, contrabass reeds, &
other brobdignagian acoustic exotica             http://www.contrabass.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---------------------------------------------------------

Date: Mon, 7 Jan 2002 16:41:45 -0800
From: Grant Green
Subject: Re: [CB] frequency the largest smoke
 

> >So the fundamental frequency for a 1/4 mile open pipe
>
>Are smoke stacks open pipe resonators? Closed? Cylindrical bore? Conical?
>Now then, what are the overtone series for this badass horn?

I'd assume its slightly conical, but have no idea if it is conical
enough to resonate as a sax vs. as a clarinet.  Maybe that should be
Ab-7 at 0.20 Hz?  I wonder if it can be "sounded" by the wind (like a
gargantuan beer bottle), or if they've taken steps to prevent that.
If they haven't, I wonder if anyone notices... ;-)

Grant

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Green
Sarrusophones, contrabass reeds, &
other brobdignagian acoustic exotica             http://www.contrabass.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
---------------------------------------------------------

From: "Patrick.Scully"
Subject: Re: [CB] frequency the largest smoke
Date: Mon, 7 Jan 2002 19:30:56 -0800

Grant,

The big natural "toot" the wind would make when blowing across the top of
the Sudbury stack could well have been a design consideration.  That other
great ultracontrabass instrument designed by civil engineers, the string
instrument once known as the Tacoma Narrows Bridge, was sounded by the wind
and played just one violent and unfinished work.   It was a nice looking
single span suspension bridge, once.

Patrick
 
 

---------------------------------------------------------

Date: Tue, 08 Jan 2002 00:59:03 -0800
From: Craig Durham
Subject: Re: [CB] frequency the largest smoke

Grant mentions the pressure / temperature differences within the stack.
Good point. There seems to be much debate among acousticians about
the behavior of waves within more conventionally-sized tubes (the 'correct '
value of the speed of sound, for instance). Are the phenomena in question
that difficult to measure, or difficult to model?

If the interior of the stack could be imaged, I wonder if one would see
rings in the soot at regular intervals.

Craig
 
 

---------------------------------------------------------

Date: Tue, 8 Jan 2002 10:18:17 -0800
From: Grant Green
Subject: Re: [CB] frequency the largest smoke
 

>Grant mentions the pressure / temperature differences within the stack.
>Good point. There seems to be much debate among acousticians about
>the behavior of waves within more conventionally-sized tubes (the 'correct '
>value of the speed of sound, for instance). Are the phenomena in question
>that difficult to measure, or difficult to model?

I suspect that these are all variables subject to change.  The speed
of sound varies with the density of the medium, which in the case of
air varies with the temperature, pressure, and humidity, which
undoubtedly varies as a wind instrument is played.  Then there is the
question of how much detail to include in a model: does one model a
woodwind with a smooth tube, or does one include the chimneys of tone
holes, with or without pads?  Are the chimney edges sharp or rounded,
or beveled, and how much?  Endless room for debate... ;-)

Grant

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Grant Green
Sarrusophones, contrabass reeds, &
other brobdignagian acoustic exotica             http://www.contrabass.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
***End of Contrabass Digest***


 
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