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Old 07-17-2008, 09:47 AM   #41
bob864
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
Originally Posted by bugz

Well, no. You wouldn't be just as out of tune. If what you say is true, you would be MORE out of tune with a delron chanter.
I meant that you'll be just as out of tune with the Delrin chanter whether the cause is due to CLTE, thermal conductivity, solar absorption, or some other factor. Therefore, while figuring out the cause of the greater degree of out-of-tuneness might be interesting, to me it doesn't really matter "why." As I said, the consensus seems to be that, all things being equal, the Delrin will move more. Given who's saying it, I think I'll take their statements at face value unless someone can offer evidence to the contrary...

It seems like a fairly easy experiment to set up though. Do it indoors, with the air conditioner running. Bring chanter A up to pitch and then stand in front of a shop light. Measure the change in pitch in terms of time and amount. Repeat with chanter B using the same reed (after an appropriate break).

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Old 07-17-2008, 09:59 AM   #42
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Default Re: ABW vs. Delrin ("plastic") Pipes

Given the tendency for ABW bias and superstition I've noted over time, all things being equal, I will reserve judgement until someone can present hard data.

Alas, I do not own an ABW chanter, so I will have to wait for valid data, preferably from an experiment conducted under controlled conditions. I'm not sure how much value the experiment you descibe would have, since you have no way to measure accurately the change in temperture from one case to the next. Was the change in temperture from the ABW case 5 degrees? Was the change in temperture in the delron case 8 degrees? Was the pressure blown precisely equal in both cases?

The devil is in the details...
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Old 07-17-2008, 10:40 AM   #43
bob864
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
Originally Posted by bugz
change in temperture from one case to the next. Was the change in temperture from the ABW case 5 degrees? Was the change in temperture in the delron case 8 degrees? Was the pressure blown precisely equal in both cases?

The devil is in the details...
If you're not certain you can blow steady, then a water manometer could be employed to verify the pressure. As far as the temperature, the A/C unit will keep the starting temperature consistent. You're correct that without a surface temperature meter (and someone to operate it) we won't know the exact temperature of the chanter, but that really doesn't matter, because we can keep the heat added constant by simply standing the same distance from the source. We're not interested in how pitch changes wrt the the temperature of the chanter, but how the pitch of the chanter changes wrt exposure to change in either a) ambient temperature or b) radiant heat.

Plotting pitch vs. time is all we really need to know to find out how much more (if any) the pitch of a Delrin chanter moves (compared to wood) when exposed to radiant heat. You could repeat the experiment standing twice as far from the heat source too and see if the shape of the curves was any different.

To test for changes in pitch vs. ambient, just turn up the thermostat and play.
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Old 07-17-2008, 11:54 AM   #44
Richard Mao
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
Originally Posted by bob864
........
Plotting pitch vs. time is all we really need to know to find out how much more (if any) the pitch of a Delrin chanter moves (compared to wood) when exposed to radiant heat. You could repeat the experiment standing twice as far from the heat source too and see if the shape of the curves was any different.

To test for changes in pitch vs. ambient, just turn up the thermostat and play.
uuuhhh... just glancing through... and picking up on this aspect of the thread late... and I might not be responding accurately...or appropriately.... if so, sorry..

Changing bagpipe pitch of the chanter over the course of a playing session is DOMINANTLY affected by three factors .... waaaaaaay before expansion/contraction of the actual chanter...

First .... ambient temperature as it changes the reed temperature from the out-of-the box ... steady state... and the reed starts changing temperature because of getting closer to the temperature of the breath being blown out of your lungs...

e.g. if you're coming from airconditioning to body temp.... the pitch will start going up...

further if you're playing in the summertime heat and sunshine in the 80 + degrees fahrenheit.... and those factors are affecting the room you are in....the pitch can go into the stratosphere...

===

second dominant factor.... moisture level of the reed.... depending on moisture control systems.... humidifying a reed from either ambient humid conditions and/or lung humidity... tends to decrease the pitch of the reed over the course of playing...

as soon as you try to change the temperature.... the humidity can change also because of the air's ability to retain humidity at different temperatures.

====

third dominant factor.... the piper's fatigue level versus his/ability to keep a constant pressure.... because fluctuating blowing/squeezing pressure has a direct result on the pitch of the reed.

So how long will it take the piper to get one chanter to steady state.... and then change the room temperature.... and play for long enough to see a difference...

and THEN repeat the exercise for the second chanter...
====

fourth, and somewhat minor, is the change if the reed hasn't been blown for a couple of days.... it's pitch will change as the reed is being warmed up..

===

I am skeptical that you can keep the above factors constant enough or controlled enough to determine/measure change attributable to change in the size/shape/dimensions of the chanter due to Delrin (note spelling please) versus ABW.... as a response to temperature change in the 5 degree range...

the odds are magnitude of your effect is buried well within the margin of accuracy of both the thermostat and the pitch meter.

let alone whether one chanter versus another was drilled by the same maker to the same target dimensions....

perhaps you can measure a band with all the same make/model of Delrin chanters.... versus another band with all the same make/model of their ABW chanters... both tuning their bands side by side on the same day.

and do a correlation coefficient or curve fit on the two scattergrams of data.

Good Luck!

(hmmm... I hope I'm having fun typing all this.... because I, otherwise, don't feel I'm making any sense..and this offshoot of the thread is almost irrelevant to the original topic)

Richard Mao, The Peking Piper ( richardmao@rocketmail.com )

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Old 07-17-2008, 12:46 PM   #45
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
(hmmm... I hope I'm having fun typing all this.... because I, otherwise, don't feel I'm making any sense..and this offshoot of the thread is almost irrelevant to the original topic)
It's relevant in that the point I'm trying to make is that the differences are probably so small that from a purely acoustic point of view, it probably doesn't make a bit of difference except at the very highest levels of piping. If that's true, then preference for one type or another is probably based purely on cosmetic preference.

So, given all the good points that Richard brings up, it seems obvious to me that we would want to eliminate as many of the extraneous variables as possible if we are just concerned with how chanter pitch will change with a change in temperature.

Both the ABW chanter and the delron chanter should be allowed to reach a steady state temperture before starting. To eliminate lung moisture and to ensure a reproducable blowing pressure, a steady pneumatic air source at the appropriate pressure should be supplied rather than relying on a human air source. Both chanters should be sounded and tuned to the proper starting pitch. The temperture in the test environment can then be increased or decreased by an increment and the changes in pitch and the differences between the two chanter types can be measured.

Of course, this is a purely academic discussion, because I am sure no one reading this forum is equipped or prepared to run such a test under laboratory conditions, but I'm an engineer, and that is just the way my mind is constructed. But for all these reasons, I am supremely unimpressed with anectodal accounts either for or against based on personal feelings and biases in the absence of valid experimental data. As this discussion points out, such stories are absolutely worthless when it comes to rigorously evaluating the accoustic properties of the delron vs ABW bagpipes.

So if you tell me that you think ABW pipes are 'better' because you think they are prettier, I'll accept that without comment, but don't try to convince me that it's because they are superior accoustically unless you have data to back up your claim, because that will trigger an immediate throwing of the BS flag.

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Old 07-17-2008, 01:08 PM   #46
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Default Re: ABW vs. Delrin ("plastic") Pipes

Those are good points Richard.

But think about this: If you're outside on a random day and it's 75F and overcast, then your chanter is probably 75F, right? If the sky clears, the ambient temperature might remain 75F, but the sun striking the chanter will make it get hot. How hot? 105F? 150F? It seems like plastic sitting in the sun gets hotter faster than wood, but that would make an interesting experiment too.

Anyway, if Delrin is a better thermal conductor than ABW (which seems likely, but not certain), then the reed would heat to a higher temperature, and it would get there faster.

So maybe plastic pipes should have a shiny silver finish to reflect away the sun's heat!

But all this is really just speculation.

I bought my pipes because they look good. As I continue to improve my abilities, they continue to sound better, and I can only dream that some day I'll such a good piper that I really need a better set, or that I'm getting so many gigs I really need a beater set.
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Old 07-17-2008, 01:42 PM   #47
Paul M Burke
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
Originally Posted by bugz

Both the ABW chanter and the delron chanter should be allowed to reach a steady state temperture before starting. To eliminate lung moisture and to ensure a reproducable blowing pressure, a steady pneumatic air source at the appropriate pressure should be supplied rather than relying on a human air source. Both chanters should be sounded and tuned to the proper starting pitch. The temperture in the test environment can then be increased or decreased by an increment and the changes in pitch and the differences between the two chanter types can be measured.

Of course, this is a purely academic discussion, because I am sure no one reading this forum is equipped or prepared to run such a test under laboratory conditions, but I'm an engineer, and that is just the way my mind is constructed. But for all these reasons, I am supremely unimpressed with anectodal accounts either for or against based on personal feelings

What a load of rubbish. You want to remove everythig that is "playing a bagpipe" and then do an experiment to find out how pitch will vary?





Better just pick up your pipes and go practice....................learn what a good pipe sounds like and learn how to make that sound.


PB
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Old 07-17-2008, 01:54 PM   #48
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Default Re: ABW vs. Delrin ("plastic") Pipes

Quote:
What a load of rubbish. You want to remove everythig that is "playing a bagpipe" and then do an experiment to find out how pitch will vary?
Not at all. I'm just demonstrating what would be necessary to resolve these recurring 'which is better' threads. If you don't use procedures like these, all these comments like 'ABW drones sound warmer' or 'cane reeds sound fuller' are absolutely meaningless.

Superstition and wishful thinking is what I see most often in discussions like this.
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Old 07-17-2008, 02:58 PM   #49
Jay Close
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Default Re: ABW vs. Delrin ("plastic") Pipes

Back in about 1975 I was at the Northern Meeting. Plastic chanters were coming on the scene and plastic drones were very experimental. Bill Livingstone -- yes, THE Bill Livingstone -- showed up to play in the Gold Medal (it may have been the Clasp) with a set of plastic drones made, if memory serves, by Warnock. This, to my mind, implies that at the highest level of competition, one of the the best players in the world was perfectly comfortable with the sound of a plastic set of drones. The big issue that day for Mr. Livingstone was condensation. He had a tenor drone stop near the very end of his tune. The other side of that coin is that he had a very long tuning period -- for which he was known. If he had begun his tune about 30 seconds sooner he would have got through in good shape.

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Old 07-17-2008, 06:59 PM   #50
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Default Re: ABW vs. Delrin ("plastic") Pipes

[SPOILER]If he had begun his tune about 30 seconds sooner he would have got through in good shape.[/SPOILER]

Would a good MCS helped? That is good to hear a delrin drone played by a world class piper.

Maybe people with both delrin and ABW pipes do a recording of each and post so all can test our ear in spotting which one is the plastic one.
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