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hitsware
Mar-20-2004, 19:24
I am looking for formulas used by organ builders for the 'Q' of a closed pipe. So far I have came up with Fc/Fp which makes sense, but sort of falls apart (I think) with shorter pipes. Any help appreciated.
TIA ........ hitsware

[Edited title to make it more descriptive]

Jamie
Mar-20-2004, 22:34
As you know the Physics of Pipe Organ "Pipe Scales" is complicated.Different Builders,Different Organs,Different Buildings/Accoustics etc. all seem to vary now.Also,The 'Q' factor is different for Flue and Reed Pipes and also the different Timbres.If you type into Google "Q Pipe Organ Pipes" there are some formulas there.Otherwise,my only other suggestion is to contact as many Pipe organ Builders as you can.They may give their "Secrets" away https://www.magle.dk/ubbthreads/images/graemlins/grin.gif. or also try "Pipe Chat" on the Web.Many Builders answer Tech Questions there. https://www.magle.dk/ubbthreads/images/graemlins/smile.gifMost Modern Organ Builders have Now gone away from the Audsley "The Art of Organ Building" set Pipe Scales.
The ('Q' = 'Quality Figure') for the resonance approx. Q = fc/f........
Works well with the Larger Closed pipes,but I agree,there is definately an impaired resonance with smaller pipes.
The Ranks of "Mutation" pipes....Many Modern Builders are just leavng them open.Good Luck anyway.Some Builder may be able to help.It could take up to 20 Pages here,if we got into a discussion,and many here are Orgel Players,not Builders/Tecnichians...also this 'Q' factor pertains to ALL accoustics and other Non Pipe organ 'Pipe' Matters.BTW if you get your qusestion on to 'Pipe Chat"...Seek out the Guy who has a Username "The Apprentice". He is in fact,One of the World's Leading Organ Builders https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

corno
Mar-21-2004, 02:26
ok, I'm not at all into much of this which you are talking about... but I'm curious... so, would anyone be so kind as to explain all these designitions and what are the values representing. https://www.magle.dk/ubbthreads/images/graemlins/smile.gif thanks https://www.magle.dk/ubbthreads/images/graemlins/grin.gif

hitsware
Mar-21-2004, 02:35
Q = stored energy / lost energy
It is how selective the pipe is to it's tuned frequency
I.E. a high Q pipe has less harmonics
Fp = fundamental of pipe (primarily based on length)
Fc = cutoff frequency of pipe (lowest note the pipe can produce (primarily based on radius))
Q = Fc / Fp

hitsware
Mar-21-2004, 02:41
>also this 'Q' factor pertains to ALL accoustics and other Non Pipe organ 'Pipe' Matters.

Yep. Thanks! ..... I'm actually using the info for ' 1/4 wave ' speakers. I figure organs have been around longer than hi-fi's so there is some good wisdom to be learned.

corno
Mar-21-2004, 02:48
hmm ok... thanks... didn't do much to enhance my understanding... but hey, it's late and a little too much physics based on terms that makes little to no sence what so ever...
is it possible to play notes lower than the (harmonic)fundamental of any given pipe? - pythagoras's teachings doesn't account for any notes lower than the fundamental. - an organ must work in sort of the same way as when you blow on the bottleneck of a bottle, or is that a wrong comparison? - so how do you get any tone lower than the "fundamental" - I can see (and hear, and play) that it's possible to "overblow" it and get the above harmonics to anygiven fundamental tuning (it's the same idea as a violin (if you press down half way you get an octave compared to the full lenght of the string - or on brass instruments when changing the tension of the embouchure/lip-buzzing or indeed a flute (which is the same way as the bottle)... but how do you go the other way? (and still have an audible sound) https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

hitsware
Mar-21-2004, 06:13
Trying to hook up a system that combines organ pipe and hi-fi technology :^)
http://f18.parsimony.net/forum31999/messages/66562.htm

Jamie
Mar-21-2004, 08:18
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifYes Corno. It is possible to produce a sound on the Pipe that is less and lower than that fundemental.Only on the Very Large Pipes though.This is illustrated on many Pipe Organs with The Stop 'Accoustic Bass 32ft".It is using a 16ft Pitch Pipe but also playing the 5th interval above it.It is OK for the bottom octave only then becomes disscordant.
eg.
CCC1 plus GGG1 (using a 16ft Open Pipe) will send it down to
CCCC1 (sounding a 32ft Pitch)
Really only used on Organ Pedal Division,and only successfull for the first 8 notes of that bottom octave.
Saves a Lot of Money and Space to do this.
If you have a Synth....Try it.!!!! Only use one tone...at 16ft....hold bottom C & bottom G (together) and within a split second,it will go down to 32ft pitch....then try bottom D and bottom A... etc etc etc. AND believe it or not...it is 'audible'.I agree,it's late and this physics get a bit crazy at this hour,but try that little trick above,and you will see it is possible.If you take a pipe at 32ft pitch and do the same (trying to produce an accoustic 64ft pitch)
it is more of a feeling of the sound than an actual audible one. https://www.magle.dk/ubbthreads/images/graemlins/crazy.gifThe secret is using the 5th interval above in combination with the fundemental,THAT will take you the 'other way' https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

Jamie
Mar-21-2004, 08:46
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifGo to other thread here "My First Organ" and you will see an Organ Company that is using some of the basics of this "Q" factor.(Hybracoustic Organreflectors)(Organs & Hi-Fi Speakers)
Quote:P.S. If you press the link Skandinavisk Orgelcentrum,or http://www.orgel.dk/ as in Frederik's first post you can download a few mp3's and hear the results.
They May help there.There is a "Full Explanation" of it on that link,however I am sure the Owner there would be pleased to help if you contact him.
I am really only "the apprentice" lol. at Pipe Chat.!!!!! https://www.magle.dk/ubbthreads/images/graemlins/smile.gifAs I said. "most here are Orgel Players"..however,it has brought out 'Corno' and his understanding of Physics within music & sound,so who knows.!!!!! there may be others with some 'input' as well.Good Luck with The Project https://www.magle.dk/ubbthreads/images/graemlins/up.gif
EDIT.
BTW. Where I live I am involved in this field..with an Organ Company..The 'Q' factor has to come out of it MOST TIMES.!!!!!!. It is a game of "trial & error".It also,as you know depends on the quality of your speakers.(can be frustrating at times..we all know the different levels & harmonics (High) that will break a Glass.There are also many (Low) harmonics that will rattle a window or something)(The Sydney Town Hall Pipe Organ has the Bottom 64ft Octave blocked off, as the vibrations would shake the foundations 'dangerously'.)(Another Organ I work with has an annoying 16ft Pedal DDD1...It rattles everything.)(All mutation stop voicing has to be carefully worked out with the Building accoustics - some work/some don't,especially the shorter pipes....some require more than one speaker etc.and different levels of 'air columns'.)BUT the expert in this field,is at the link I have given above....Will get back to you with Further Reading Matter. https://www.magle.dk/ubbthreads/images/graemlins/smile.gif
Aug.Laukhuff in Germany did have all the Pipe Scales listed in their catalogue..(Old & New Scales).Again,they are also very approachable for Questions of this nature.

corno
Mar-21-2004, 14:47
ahh... - that makes perfect sence now... after having slept for som 8 hours since 5 am... https://www.magle.dk/ubbthreads/images/graemlins/smile.gif -but hey... that's "cheating"... producing sounds not inherent to any given pipe plus the fundamental of the pipe - that's not really possible that many other places in physics. - double-tones and harmonical addition and subtraction is also a part of horn playing where you get normally 3 or 4 tones when you sing one and play aonther (inside the horn)... https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

**DONOTDELETE**
Mar-21-2004, 19:13
Thanks Again. Here's my conundrum:
Please correct any errors of formulas.
For a closed pipe (c = speed of sound)
Fp = c / ( 4 * ( length + ( .6 * radius )))
Fc = c / ( 2pi * radius )
With a pipe of 0 length (flat baffle) you get a Q of ~ .38
???????? Should be 0 I would think........

Jamie
Mar-21-2004, 21:28
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifGlad you got some sleep.OK!!! it is cheating & it is the most,but least effective way of producing this 32 ft pitch.
Let's try this one:
When pure tones (sine waves) are sounded together, they combine to produce two additional tones whose frequencies are the sum and difference of the two original tones. For example, if the original frequencies are 32hz and 48hz, the resultant frequencies will be 80hz and 16 hz. While this effect occurs at all frequencies, it is most effective to the human ear at low frequencies. (This same acoustical principle is used by celestes to produce a different effect.)

These stops use this acoustical effect to produce tones in the 32' and 64' octaves, using smaller (and thus less costly) pipes than would normally be necessary. One of these stops, labeled as 32' or 64' pitch, is comprised of two ranks which sound an octave and a twelfth above the desired pitch (that is, at the 1st & 2nd harmonics). For a 32' stop, the two ranks are 16' and 10-2/3'; for a 64' stop, the two ranks are 32' and 21-1/3'.

In many cases both pitches are taken from the same rank of pipes, a fifth apart, as a further cost-saving measure. Because 5ths in the equal-tempered scale are not perfect fifths, the resultant tones will not be quite in tune, but it works because the human ear does not hear such low tones with enough accuracy to tell the difference.

The name Gravissima is typically only used for a 64' stop.

N.B. There are exactly two true 64' stops in existence. One is the Diaphone Profundo at Atlantic City; the other is a Contra Trombone at the Sydney Town Hall.
Tonal Attributes
In order to be effective, the pipes should be large scale flues, either open or stopped. Bourdons and Diapasons are most often used; reeds are almost never used.
Usage
This stop is a replacement for a true 32' or 64' stop. It is not as effective as a true stop, but is often the only economical way to obtain 32' tone in a modest instrument. It is almost invariably found in the pedal.
Variants
A single 5th sounding stop at 10-2/3' or 21-1/3' pitch is often provided to achieve the same effect. This has the advantage that it can be combined with a variety of octave sounding stops. See Grossquintenbass.
Examples
32' examples are fairly common. 64' examples are rare, Julian Rhodes keeps a compilation by David Willey that lists about 40 examples (see Bibliography below). A few examples are listed here.

Gravissima 64'; Woolsey Hall, Yale University, New Haven CT; Hutchings-Votey Organ Company.

Gravissima 64'; Worcester Cathedral, Worcester, England; Hope-Jones.

Gravissima 64'; Liverpool Cathedral, Liverpool England; Willis.

Gravissima 64'; Bremen Cathedral, Bremen, Germany (destroyed?); J. F. Schulze.
_____________________________________end.

Now corno,at this hour in the morning I had to resort to going to The Bible for Organ Builders & Organists. lol.

http://www.organstops.org/ Click Middle link on page & all
sorts of things appear about pipes and also somewhere in there is all about this 'Q' factor (I think).

hehe https://www.magle.dk/ubbthreads/images/graemlins/grin.gif I forgot I was talking to a Horn Guy,and you would have been aware of all this double-tone & harmonic minus's and plus's etc.I do understand this '(inside the horn)'.Us keyboard players and other intrumentalists have all the Keys in front of us.But you Horn Players (and Strings) have a lot more to do to produce sounds.I admire all the hard work required and https://www.magle.dk/ubbthreads/images/graemlins/up.gif for more use of the Brass Section in new works.etc.
So I have to fully agree with Pythagoras (let's not disturb him now) and also in answer to your question,NO.!!!! there is no real way that you can produce an 'audible' & 'true' sound BELOW its fundamental.(without cheating).Also,your 'bottleneck' comparison is a very spot on way of understanding the upper harmonics. etc.
Many have tried. Haskell was one who tried in the early 1900's of taking a pipe and inserting another pipe to try and lower pitch,without lengthening the pipe (was also tried in the early 17th cent in spanish organs)."Haskelling" a pipe is sometimes still used now,but not very good results.
I am sure Haskell and other methods are in The Bible at above link.The mutation section is interesting,in relation to the higher notes.....this is where,I think, the 'Q' factor is explained better.
Time for a coffee break. Jamie https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

Jamie
Mar-21-2004, 21:36
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifahah....hitsware/anonymous. That is right.!!!!! Will let Corno look at it first.Also will run it by a few others,but it looks OK to me https://www.magle.dk/ubbthreads/images/graemlins/up.gif YES!!!!! I think it would be 'O'... but will get back after a few Pipe Guys confirm your formula. SORRY this has appeared after all of my 32' & 64'
rambling,but did not see your post until after. wooooosh this stuff does get interesting & what forums are all about.
have linked/hooked up with that url....also read many of the tech ?????? there as well..Hi-Fi = Hi-Tech lol https://www.magle.dk/ubbthreads/images/graemlins/grin.gif

hitsware
Mar-22-2004, 03:47
http://www.quarter-wave.com/

This guy takes it to the max but his program runs in 'Mathcad' which is clunky on my machine......

Jamie
Mar-22-2004, 12:01
Full acknowledgement and Thanks is given to:

The Encyclopedia of Organ Stops: copyright © 1999-2003 by Edward L. Stauff.
Permission is granted to use small excerpts from this work for educational and/or non-profit purposes, as long as due credit is given to the author.

Copying in whole, or in large excerpts, via any medium, is expressly forbidden without written permission from the author, with the exception of quoted material in the public domain, or quoted material covered by another copyright.

Any for-profit use is likewise forbidden without written permission from the author.
____________________________________

This is for using The section on Resulant Bass 32' in previous post from the URL link given there.
Jamie. https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

Jamie
Mar-22-2004, 21:03
I have added the Question to "Pipe Chat". But ALL here(that's where I work) and All Australian & Overseas Builders I know of Pipe Organs feel that You have the Formula Right.
It fits right with Audsley in his, "The Art of Organ Building" and those 2 volumes are still The Bible for ALL Organ Builders today.
They did go to: (google- 'Q formula pipe organs')
http://www.nmol.com/users/wblocker/orgnpp.htm
but it lost me then. lol. I guess that you have done the same in all sorts of combinations & other search engines.
The other url you gave..(quarter-wave)..the guy there certainly does take it a long way,and he has many related links as well.more up your sleeve than mine.lol.
I am sure you have it now & hope things go well.
Hope it has been some help.The Old Saying!!! "there is no harm done in asking & is the way to learn etc".
Jamie https://www.magle.dk/ubbthreads/images/graemlins/smile.gif
ps. hope you will stick around MIMF.???!!!

hitsware
Mar-22-2004, 22:08
>I am sure you have it now.......
Nope. I've been working on this for months (on and off)
One of the gurus on the Full Range Forum says an OB (open baffle) cannot even be considered a 0 length pipe, but has no answer for when a pipe stops being a pipe. BTW the 'organ reflectors' appear to be TQWP 'tuned quarter wave' type speakers. Does each 'reflector' cover the full keyboard or only a part? Thanks Again. This IS a way groovy forum(s)............

Jamie
Mar-23-2004, 22:20
Hi hitsware. I am off to see my Tutor/Boss in hospital today (6am Wednesday here).From there I am meeting with several at My Uni (University of Queensland) and the Institute of Technology Colleagues.Will have this "Q"matter sorted out 'once & for all' lol.You say 'Nope' and a Guru told you,I would have thought to tell you NO,he would be able to tell you WHY.????? (not being rude). Also I notice you have 2 "New" Threads put in and will answer those EASY as well when I get back from Brisbane.But glad you have decided to stick around,it is a 'Groovy' Forum/s.Will be back at YOU in 24 Hours lol, with Some POSITIVE answers.
Jamie https://www.magle.dk/ubbthreads/images/graemlins/smile.gifThe 'Q' Matter is posted at Pipe Chat and every Organ Builder is at work on it.lol. https://www.magle.dk/ubbthreads/images/graemlins/grin.gif

Jamie
Mar-24-2004, 03:07
Just have a Gander at this:
http://users.iafrica.com/k/ku/kurient/dsp/algorithms.html
The 'Q' is right down the bottom of Page. Running Late Now.
CYA a bit Later. Jamie https://www.magle.dk/ubbthreads/images/graemlins/smile.gif
That came from: http://www.thefreecountry.com/sourcecode/audio.shtml

**DONOTDELETE**
Mar-24-2004, 05:54
"q: The Q-Factor (or steepness) of the bandpass filter. The smaller the value, the steeper the filter (and the more unstable the filter). Practical values range from about 1 to about 0.01."
This applies to his DSP code, but the numbers don't jive with the 'Q' we're looking for. A real organ pipe has a Q ~12 (Sir Walter Raleigh) and speakers ~ 1........The search continues ....... https://www.magle.dk/ubbthreads/images/graemlins/nut.gif

hitsware
Mar-25-2004, 07:21
"q:" "The smaller the value, the steeper the filter"

this is backwards to the Q of which we speak ....
BUT ..... ????????????????
......... https://www.magle.dk/ubbthreads/images/graemlins/nut.gif

Pamadu
Mar-25-2004, 22:06
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifmmmmmmmmmm That 'Lord Raleigh'link I gave to Jamie,sort of does make the search continue.Now I am back on deck,will look further for you as well. Cheers https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Pamadu/Paul.

Pamadu
Mar-27-2004, 12:08
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifA lot of people are pointing me to this link:
http://www.pykett.org.uk/how_the_flue_pipe_speaks.htm

Yes...It explains a lot....BUT most important is a Reference at the bottom of page in Section on "Pipe Scales" and especially under further reading:
3. “The Physics of Organ Pipes”, N H Fletcher, Scientific American, January 1983, p 94
Did have a copy of this,but now lost. So the search will continue.Could be worth contacting the Author of that article.(Colin Pykett)?????? Cheers https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Pamadu/Paul.

hitsware
Mar-29-2004, 01:16
"The reason why the natural frequencies are not exact multiples of the fundamental is because of the end corrections of the pipe, which cause it to seem rather longer than its actual length to the travelling impulses. The end corrections at the mouth and top (if open) result partly from the impulses overshooting the pipe ends somewhat, and the mouth corrections dominate those at the open end. The total end correction (mouth plus end) is greatest for the lowest frequencies and it also increases for wider pipes. These two effects taken together mean that the natural frequencies for wide pipes do not coincide well with the harmonics of the forced excitation when the pipe is sounding. The teeth of the two combs lie progressively further apart in this case, as shown in Figure 4, although this diagram has been exaggerated for clarity. This means that such a pipe does not amplify the harmonics of the forced excitation very well beyond the fundamental and first few harmonics, thereby producing a frequency spectrum characteristic of a flute."

Ya Mon! Great link. Just touches on 'Q' but the quote above is great. I've done some experiments and wondered about the weird harmonic structure......... https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif

Jamie
Mar-30-2004, 02:09
My Boss & Tutor etc.,knows Colin Pykett and later today here will email him and see what he knows about 'Q'.
It is a Good Link that. I have many more,but was hoping that 'Pipe Chat' would come up with answer by now.Will try again.It's all just https://www.magle.dk/ubbthreads/images/graemlins/cool.gif and very interesting https://www.magle.dk/ubbthreads/images/graemlins/up.gif
Jamie. Better go do some work/study now https://www.magle.dk/ubbthreads/images/graemlins/grin.gif too early here for a https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif but it is heating up. hehehehe

Pamadu
Mar-30-2004, 02:30
Will contact a Few Others today, as well as this Guy:
http://homepages.tig.com.au/~audio/audio/gadgets.htm
Cheers https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Paul.
P.S. Type into Google....Q formula for sound.... many articles there as well.

hitsware
Mar-30-2004, 06:05
length / diameter ......... right ???????

Pamadu
Mar-30-2004, 10:03
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifSounds Good to Me "hitsware".!!!!!! https://www.magle.dk/ubbthreads/images/graemlins/up.gif Will get Jamie to gather a few more people as well (to Join Up), and in a few days when I have a Backlog of work out of the way (after an illness).
The MAX........it is.!!!! https://www.magle.dk/ubbthreads/images/graemlins/grin.gif Cheers https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Pamadu/Paul

hitsware
Mar-30-2004, 17:06
Yea. Seems in this disipline 'scale factor' is used much more than 'Q'. It's a new system to me, but the results should come out equivalent. The 2 (sf (interestingly there is a 'sf' in speaker building, but it is 'size factor' and pertains to where in the room you locate your speakers)) and Q are definately related.

hitsware
Mar-31-2004, 05:46
http://kosat.consultit.no/~ketil/lowther/bigfunht.html#HD_NM_14 .....

full space ... 1/2 space .... 1/4 space ... 1/8 space ... ??

Jamie
Mar-31-2004, 09:58
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifIt is a difficult one...Everywhere you go and think you have it,something else comes up.At the moment I am looking at Leslie 'Old' tube horns. That last link threw me off in another direction.

'Q'

Q is the formula for what happens electrically and physically at resonant frequency. Q is related to how slowly a natural vibration dies down. Q is a neat term that combines many elements of speaker design, so it's an important term to speaker designers.

Q is important to the woofer because in a speaker system where the Q is too high, you'll get a whomp in the bass. If a speaker system's Q is too low, then the bass output is relatively weak, because frequency response is highly damped in that region.

The best Q for a speaker to have is one that gives flat response down to the resonant frequency.

If you do nothing to a speaker but make the cabinet smaller, you increase stiffness and therefore Q goes up. But Q is not a word for stiffness alone. It's a ration involving mass, stiffness, and resistance (or damping). Designers often juggle these three factors. Good bass is not enough. Good bass with uniform frequency response and spherical wave-form is the goal. Obtaining that goal without too much sacrifice in efficiency is the challenge.
______________________________ will be back a bit later..... Yeah 'Challenge'.Jamie https://www.magle.dk/ubbthreads/images/graemlins/up.gif
I put that in for a reason LOL now can't remember why.
have not had any sleep for 18 hours so https://www.magle.dk/ubbthreads/images/graemlins/snore.gif and be up in the early hours of the morning. https://www.magle.dk/ubbthreads/images/graemlins/grin.gif

Pamadu
Mar-31-2004, 15:29
https://www.magle.dk/ubbthreads/images/graemlins/smile.gifJust to confuse all of us:

a "Q" sound calculator:

http://www.csgnetwork.com/speakerqestcalc.html

I need a https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Pamadu/Paul.... I also notice a lot of Other Calculators on this Page https://www.magle.dk/ubbthreads/images/graemlins/nut.gif

**DONOTDELETE**
Mar-31-2004, 18:16
That is a differant 'Q' than the one Jamie talks of. (which I think is the same one used with organ pipes). It brings out a good point. 'Q' (quality factor) can be anything you want (depending on the 'quality' you are looking for.) 'Q' in one system could concievably be 1/Q in another !

Jamie
Mar-31-2004, 21:08
Q factor
From Wikipedia, the free encyclopedia:

http://en.wikipedia.org/wiki/Q_factor

And that's the Confusion.!!!!!!!!! https://www.magle.dk/ubbthreads/images/graemlins/confused.gif I think. when reading & asking. 'Q' CAN be anything you want.????????? etc etc as you have said.
Jamie. https://www.magle.dk/ubbthreads/images/graemlins/smile.gif

Pamadu
Mar-31-2004, 22:00
https://www.magle.dk/ubbthreads/images/graemlins/smile.gif This is the "Danske" link as above. May help more for some people:
http://da.wikipedia.org/wiki/Godhed_%28elektronik%29

tak. https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif Pamadu/Paul.

hitsware
Apr-01-2004, 02:26
>And that's the Confusion

I don't think so if we are sure we are speaking in the context of organ pipes. 'Q' = Fc / Fp .....VERY associated with 'scale factor' .......

Jamie
Apr-02-2004, 12:43
https://www.magle.dk/ubbthreads/images/graemlins/cool.gif Your Quote 'Yea. Seems in this disipline 'scale factor' is used much more than 'Q'. It's a new system to me, but the results should come out equivalent. The 2 (sf (interestingly there is a 'sf' in speaker building, but it is 'size factor' and pertains to where in the room you locate your speakers)) and Q are definately related.'

The formula is Correct. Q = Fc/Fp . but it does make a big difference on the type of pipe etc.and Accoustics etc. but agree that the when using this formula it should come out right.....but there are some other reasons,I have found.and also been told. Will be back tomorrow after all this Birthday thing is over....I have to sober up as well. https://www.magle.dk/ubbthreads/images/graemlins/grin.gif Jamie.

Pamadu
Apr-02-2004, 22:51
Just have a look at this Link (there are 15 Pages to click at the Bottom). It gives a little about The Physics of Organ Pipes......However,by No Means The answer we seek.

http://rjweisen.50megs.com/fluepipe1_001.htm

It does help to see a few things. Cheers https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gifPamadu/Paul.

hitsware
Apr-03-2004, 01:57
What exactly is 'cutup'? Simply the opening in the pipe (assuming a closed pipe)? Yea....a toroidal pipe https://www.magle.dk/ubbthreads/images/graemlins/nut.gif

Jamie
Apr-03-2004, 02:19
https://www.magle.dk/ubbthreads/images/graemlins/smile.gif 'cutup' is:
Completed pipes are ready to be voiced. Voicing is the process of adjusting the physical alignment of the critical parts (upper and lower lips, languid, etc.) to get the desired sound.This process begins by establishing the CUTUP, which is the distance from the lower lip to the upper lip of the pipe. Proportional dividers are used to etch a line across the upper lip of the pipe. Principal stops are often cut up 1/4 of the width of their mouth and Flutes are often cut up 1/3, but this depends on the tone desired. Higher cut ups increase the power of the pipe at its fundamental and decrease its upper harmonics.
see: http://www.ruffatti.com/ruffatti_pipes.html

Jamie https://www.magle.dk/ubbthreads/images/graemlins/cool.gif

EDIT;
see also: http://mmd.foxtail.com/Archives/Digests/199903/1999.03.24.05.html (Last Paragraph)

Mr Bullock at Dallas Pipe Organs answers a lot of Pipe organ Difficult Questions. Commodore Pamadu knows him and will direct him to here,and see if He can have some input as well....He will tell you that 'Builders' guard their Voicing/Scales like Fort Knox....and we modern builders are really compiling the parts made from around the world.
'Compilers' we are. lol. https://www.magle.dk/ubbthreads/images/graemlins/grin.gif as there are ONLY a FEW Pipe Making Workshops now in the World. One here in Australia.Was 'Fincham's' Organ Builders.in Victoria down south.It is now used by a Queensland Builder,so should not have much trouble getting on to them.(Fingers Crossed) https://www.magle.dk/ubbthreads/images/graemlins/up.gif

hitsware
Apr-03-2004, 03:55
http://mmd.foxtail.com/Archives/Digests/199902/1999.02.04.01.html

http://www.rose-hulman.edu/~moloney/AcousticWork/QualityFactorsofCylindricalPipes.html

http://people.bu.edu/mbutulis/pipes.html

http://scienceworld.wolfram.com/physics/Q.html

http://mmd.foxtail.com/Archives/Digests/199911/1999.11.05.03.html

here's some links I've 'compiled' https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gif
Thank You !

Pamadu
Apr-03-2004, 09:55
https://www.magle.dk/ubbthreads/images/graemlins/smile.gif Have seen all those links and the one to look at closely,because we are dealing with the "Damping of Harmonics" (Plenty at Bottom but less at Top as in your First Posts) is:
http://scienceworld.wolfram.com/physics/Q.html
Also try your Tecnichal Library for Audsley "The Art of Organ Building" (2 Volumes) also "The Physics of Organ Pipes" & basically "Q" can be anything....depending on the
Discipline you are Working in.
Having a few days to catch up on Music....and Jamie is off to Melbourne,Victoria...Next week. He will be seeing David Fincham while there and He is about the Only Guy left in Australia who can probably rattle it all off. His Father George Fincham would have known.I have contacted Dallas Pipe Organs,and await their reply.
Cheers or too much Cheers. hehehehe https://www.magle.dk/ubbthreads/images/graemlins/cheers444.gifPamadu/Paul.
P.S. Let's Hope that a few More come in on this....They should....as it is all over The Web.!!!!!!!!!!!!!!! https://www.magle.dk/ubbthreads/images/graemlins/grin.gif

Contratrombone64
Dec-06-2007, 05:21
Now this thread needs to be read, then re-read, etc etc until absorbed. Obviously my cerebral capacities are too low ... most vexing.

Corno Dolce
Dec-06-2007, 07:59
Yes, CT, it is a most invalueable knowlege one should know in order to be an adept organbuilder.

Cheers,

Corno Dolce