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Twice as Long and Half as Short
4

Twice as Long and Half as Short

Twice as Long and Half as Short

(OP)
Yesterday, at my church, I went to a "Get to Know the Pipe Organ" event (sounds kind of boring, I know, but it was actually interesting).  Anyway, the handout said that pipes that are "twice as long" produce a pitch that is an octave lower, while pipes that are "half as short" produce a pitch that is an octave higher.  The engineer in me thought, shouldn't that be "half as long"?  And is a pipe that is "half as short" actually the same length as a pipe that is "twice as long"?

DaveAtkins

RE: Twice as Long and Half as Short

Divide by 2 or multiply by .5.

I'm with ya.

RE: Twice as Long and Half as Short

As one of my associates would say - "you're on the wrong side of close."

RE: Twice as Long and Half as Short

I hear you Dave.  We have a product at our company described as "1.55mm thin".  I guess the word 'thick' does not provide sufficient emphasis for this small part.    

RE: Twice as Long and Half as Short

Your right, it makes no sense.  You could just as easily say twice as short.

RE: Twice as Long and Half as Short

I've heard the expression "half as short" all my life in the parts of the U.S. that I've lived in (Oklahoma and Texas).

It simply means half the length.

NozzleTwister
Houston, Texas

RE: Twice as Long and Half as Short

I have a one foot pipe.

Twice as long = two feet
Half as short = 1/2 foot

This is correct english is it not?

"Do not worry about your problems with mathematics, I assure you mine are far greater."   
Albert Einstein
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RE: Twice as Long and Half as Short

Re-reading my own post, it struck me that twice as short actually means half as long.

RE: Twice as Long and Half as Short

Ashereng,

Yes it is correct English.

NozzleTwister
Houston, Texas

RE: Twice as Long and Half as Short

It seems you (we?) guys can't agree.  In my area I'm often asked to compare execution (of computer simulations) speeds.  Half as fast? Twice as fast? I normally end up giving it long-hand: "an execution time of 50% of the baseline".

RE: Twice as Long and Half as Short

We have not noticed the theme of the event "Get to Know the Pipe Organ", which really, is the context.

It would have been simpler and elegant to say "half as long", oh yes. But that was not the point. The point that is being made is "Longer = lower pitch" and conversely, "Shorter = higher pitch". That is the reason "short" is used in the sentence.

Try saying "half as long," and the whole point is missed. Whereas now the correct relationship will be registered in the audience's mind. Instructional design relies to an extent on psychology and pedagogy.

RE: Twice as Long and Half as Short

Quote (Ashereng):

I have a one foot pipe.

Twice as long = two feet
Half as short = 1/2 foot

This is correct english is it not?
I would say not. It is English, but IMO it is poor English.

Twice the length or half the length would be more correct.

... and as for having a "one foot pipe" ... heh, you should be so lucky. tongue

cheers
Helpful SW websites  FAQ559-520
How to get answers to your SW questions  FAQ559-1091

RE: Twice as Long and Half as Short

You're just lucky they didn't get into percentages.

Ie: "200% longer produces an octave higher" (Should be 100% longer or 200% of the original length)

And 50% shorter just makes my brain hurt.

RE: Twice as Long and Half as Short

Except that 200% longer would produce an octave and a major fifth lower, not higher.
Sorry, those nits just needed picking. ;)

RE: Twice as Long and Half as Short

NIT ALERT!

No such thing as a "major fifth" - because the dominant of major and minor scales is the same, the interval is called a "perfect fifth".

The "octave plus a fifth" interval you get from a 200% increase in resonator length is usually just called a "twelfth" - and against all reason is also the interval you tend to get if you overblow a cylindrical pipe (which is why most woodwind instruments are tapered).

A.

RE: Twice as Long and Half as Short

Oops. Best to get em while they're still nits.

RE: Twice as Long and Half as Short

stevenal wasn't wrong, but rather pointing out a potential incorrect use of percentages.  (The info in parentheses was correct.)

12th as first harmonic in a pipe is not against all reason.  It's because the easy modes of vibration have a node at the blown (closed) end and then are open at the other end.  So the pattern would be 1/2 standing wave, then 1 1/2 standing waves, then 2 1/2, etc.  The jump from 1/2 to 1 1/2 is a threefold increase.  

Here, these folks say it better than I do:
http://www.phys.unsw.edu.au/~jw/pipes.html

Hg

Eng-Tips policies:  FAQ731-376

RE: Twice as Long and Half as Short

Sorry, Zeusfaber.  You're right.  My music training is 30 years rusty.

RE: Twice as Long and Half as Short

I had meant the quoted part to be wrong, not doubly wrong. Here is what I meant to say:

"200% longer produces an octave lower" (Should be 100% longer or 200% of the original length)


RE: Twice as Long and Half as Short

"Half as short" is confusing. Don't use it.

It only gets 321 hits on google.

RE: Twice as Long and Half as Short

I like the terminology major fifth, because I can easily refer to the interval which is one-half tone less as a minor fifth.

So what do you call it... an imperfect fifth?

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RE: Twice as Long and Half as Short

In fact, it should have been "twice as short" to really mean half as long. Now, that sounds good to me as much as it makes perfect sense.

.

RE: Twice as Long and Half as Short

electricpete--it's a diminished fifth or an augmented fourth.

Hg

Eng-Tips policies:  FAQ731-376

RE: Twice as Long and Half as Short

Ah.  I remember that now. Too long ago... too many cobwebs.
Thx.

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Eng-tips forums: The best place on the web for engineering discussions.

RE: Twice as Long and Half as Short

electricpete ... don't you mean too short ago? wink

cheers
Helpful SW websites  FAQ559-520
How to get answers to your SW questions  FAQ559-1091

RE: Twice as Long and Half as Short

Good one!  Maybe I should've said that I don't remember because it was not short enough ago.

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Eng-tips forums: The best place on the web for engineering discussions.

RE: Twice as Long and Half as Short

The augmented fourth has enough names already.  As well as "diminished fifth", it also answers to both "tritone" and "diabolus in musica".

A.

RE: Twice as Long and Half as Short

Zeus was right about the perfect fifth which is the dominate in the current key, blah blah.  It's the third that establishes the major/minor status and the sixth and seventh set the types of minor scales.

In any case, Bach rules the roost in music theory and pipe organs.  Do you know why he had so many children (20)?

His organ didn't have any stops.

RE: Twice as Long and Half as Short

Too many Hymns & not enough Hers?

cheers
Helpful SW websites  FAQ559-520
How to get answers to your SW questions  FAQ559-1091

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