[Bell Historians] Carillon

[Bickerton, Roderic (SELEX GALILEO, UK)]

"There will be no point in tuning the proposed bourdon of 75t, 
certainly not in any any conventional sense, because any partial we 
normally talk about will be way below the audible range. I would 
guess such a bell would have a nominal of about 180Hz. All one will 
hear is a low-pitched tuneless crash."

 
That's an interesting one, which I do not believe.
For starters, 180HZ is over 3 octaves above a 32Ft pipe.
 
The human auditory range is said to extend to 16HZ, which just happens
to be the bottom of a 32ft stop.
 
I have a speaker system that extends to about 20, (IMF TLS80's, fully
characterised).
I have done some experimentation with very low frequency sound, years
ago and not aimed at detecting pitch.
I do remember that pitch can be discerned, although it takes longer and
I suspect there is loss of accuracy.
There are some wonderful low frequency organ sequences in "Symphony
Antarctica" a cadence of almost ever decreeing frequency notes, most
impressive, a more sensual than audible experience.
To suggest the effect could be generated by just playing the same note
repeatedly, no way!
 
Its probably true that most of us would be quite unable to pitch an
isolated single low frequency sound but the ear is rather good at
detecting the difference between a sequence of notes.
 
Its  fact that very few people ever hear extreme low frequencies, as an
isolated sound, intended to be heard as such.
Most sound reproducing systems give up some ware between 70 and 100HZ,
and few "hi-fi" systems get much below 50. 
 
Since almost all low frequency sound is unwanted noise most of us learn
to "turn off" listening to it.
Appreciating low frequencies is something I had to learn (years before I
learnt to ring).
 
Some organs actually have a 64ft, Just over 8Hz, Liverpool Cath for one,
although I have no idea why.
 
A demonstration of 12HZ at a sound pressure of 100dB was to me totally
inaudible.
 
It went like this, a friend of mine, Rex Baldock and a sound expert had
a house with a folded 18Ft  horn speaker built under the floor. I, with
others were invited in and asked if we could hear anything, none of us
could.
Rex then pulled out a "Daw" sound level meter and switched it on.
inexplicably it read 100dB.
He then unfolded a sheer from the Telegraph and placed it over the floor
grill where sound from the horn entered the room.
It lay flat about 1" from the floor, apparently suspended on nothing.
Rex then turned down the Amplifier, the paper descended and the sound
meter fell back to about 50, all with no apparent change in sound levels
within the room.
 
Could I have an example of an organ with an open, or even a stopped 32
reusing pipes?
I have crawled round a number, over 50 years and have never noticed one.
Rod.
PS
If someone wanted to build a huge pipe rank would not 96 make more sense
than 64 as it could be over blown to produce the loudest ever 32?
An open 64' could be downright dangerous as it can generate human body
resonance frequencies (7 to 12HZ?).

________________________________

From: bellhistorians at yahoogroups.com
[mailto:bellhistorians at yahoogroups.com] On Behalf Of Bill Hibbert
Sent: 21 August 2008 22:00
To: bellhistorians at yahoogroups.com
Subject: [Bell Historians] Carillon


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There will be no point in tuning the proposed bourdon of 75t, 
certainly not in any any conventional sense, because any partial we 
normally talk about will be way below the audible range. I would 
guess such a bell would have a nominal of about 180Hz. All one will 
hear is a low-pitched tuneless crash.

However, this is a fantastic cost saving measure, because the bottom 
half dozen or more keys on the keyboard or clavier can all play on 
the same bell, and no-one will know any different. (This is an old 
organ-builders trick for 32 foot stops.) To avoid each of the keys 
producing an identical tuneless crash, each hammer could hit the bell 
at a different point moving up from the lip towards the waist.

To have the bottom nine semitones (i.e. everything with a nominal of 
less than 300Hz) all play at different points on the same bell will I 
estimate save about 315 tonnes of metal. With enough bells, arranged 
artistically, no-one will think to count how many there are.

Bill H



 


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