Organs and articulation

[Dave2002]

A question which came up yesterday after a discussion about playing music in Irish folk style on wind instruments - for example whistles.

How fast can an organ articulate rapid notes? Is there a significant delay between the onset of a note and cutting it off? This might depend on whether the notes are different, and sounded on different pipes, but originally we were thinking of rapid articulation on a single pipe.

In some folk music - played on whistles - the player does not interrupt the air stream, but uses fingering to insert 'cuts' and 'taps' - also 'rolls', which may serve the purpose of tongued articulation. In the case of penny whistles, tongued articulation is, of course, still possible. Similar fingering techniques - which may sound like ornaments - are also used for bagpipes, in which tongued articulation is not, AFAIK, possible.

So what we were wondering was whether similar considerations applied to organs, and also if these issues might have had an impact on organ music, ornaments and articulation generally for those instruments.

[Keraulophone]

If one blows into a basic flue organ pipe, the sound is usually instantaneous, as it would be from, say, a treble recorder. Differently sized pipes and types of organ pipe would behave in very different ways, however, as would a bass recoorder differ from a soprano one due to the longer column and greater volume of air needed to produce the sound. Some reed pipes may have a longer delay, especially if they are of 16ft or 32ft length. Stopped pipes require the air to travel both up and down the pipe, producing a sound one octave lower than an unstopped pipe, which may add a slight delay. Clearly, it is the job of the skilled organ builder to get all ranks of pipes to speak simultaneously, though that is rarely achieved with certain deep pedal pipes, which, in any case, approach the lower limit of human hearing.

Further to varieties of organ pipe, the type of key action has to be considered. Mechanical action organs are presently in vogue, though a very large instrument, or one distributed in different parts of a building, may necessarily have to have some kind of electronic or electro-pneumatic action because the trackers would be too long and the key action too heavy, especially if manuals were coupled together mechanically.

"The release time of an action is approximately proportional to the square root of the masses in the action."

If you'd like to read about the physics of repetition rate, be my guest - http://www.pykett.org.uk/the_physics...ate%20-%20Mech

Simpler observations about tracker or mechanical action in pipe organs can be found here: https://www.quora.com/What-is-so-gre...in-pipe-organs

...from which I have extracted (and slightly edited) the following:

"The biggest benefit of mechanical or tracker action in organs is the direct control of the pallet, which is what allows air to enter the pipe. It is possible to control the speed and to some extent the speech of the pipe, much the same way speech can be controlled in a wind instrument. With mechanical action you can control both the attack and release of the note, but with electro/pneumatic action it can only control when they occur.

It is often thought that tracker action provides a cleaner, more articulated sound in rapid passages, but just as many people would claim no audible difference in that situation between mechanical and electro-pneumatic actions. The weight of the action when divisions are coupled is a consideration as you're doubling or even tripling the weight of the action when keyboards are coupled together."

'Might [these issues] have had an impact on organ music, ornaments and articulation generally for those instruments?' Definitely: most organ music has been written for the most advanced instruments of the day, not forgetting former organs of note. There are old treatises on fingering, ornamentation and the like written before and after J S Bach which give an indication as to how we might approach an early score today. In practice, we have to use the local resouces available, even if it means playing Bach on the Father Williis of Truro Cathedral rather than on the 17/18thC Renatus Harris/John Byfield organ which resides unplayed in the lady chapel of said cathedral. But that's another story.

I hope some of this helps.

[Dave2002]

"The release time of an action is approximately proportional to the square root of the masses in the action."

If you'd like to read about the physics of repetition rate, be my guest - http://www.pykett.org.uk/the_physics...ate%20-%20Mech


...from which I have extracted (and slightly edited) the following:

"The biggest benefit of mechanical or tracker action in organs is the direct control of the pallet, which is what allows air to enter the pipe. It is possible to control the speed and to some extent the speech of the pipe, much the same way speech can be controlled in a wind instrument. With mechanical action you can control both the attack and release of the note, but with electro/pneumatic action it can only control when they occur.



'Might [these issues] have had an impact on organ music, ornaments and articulation generally for those instruments?' Definitely: most organ music has been written for the most advanced instruments of the day, not forgetting former organs of note. There are old treatises on fingering, ornamentation and the like written before and after J S Bach which give an indication as to how we might approach an early score today. In practice, we have to use the local resouces available, even if it means playing Bach on the Father Williis of Truro Cathedral rather than on the 17/18thC Renatus Harris/John Byfield organ which resides unplayed in the lady chapel of said cathedral. But that's another story.

I hope some of this helps.

Thanks very much.

One point, obviously (!!) with a wind blown instrument, and that includes organ pipes, some air flow is required. However, I don't think (much) air actually has to flow through the pipe - the aim is to get the air in the pipe to resonate, and that presumably is done by the vibrations set up by the air flowing over the fipple (in a recorder). Perhaps even some other noise source could be used, and the pipe then would act as a sort of resonant filter. OK - maybe ideally the sound source should be close in pitch to the desired pitch, but essentially pipes are resonating tubes normally filled with air, and the air blown into them is simply to initiate the sound source for the resonating to occur, rather than having to flow through the whole length of the tube.

I note the comments about some disagreement about whether electro-pneumatic or tracker action organs are more responsive. I always thought tracker action organs were more responsive, but presumably those don't work with very large organs.

Is the pallet simply an "on/off" valve blocking the air which is supplied by the pump?

Going back to the origin of my original question, does anyone know where the 'cut', 'tap' and 'roll' features of whistle music (folk style) came from? Seems odd that players of whistles would want to blow continuously, then try to articulate by using fingering to give very rapid and alternating pitch shifts. These may be ornamental, but are hardly the same as "proper" tongued articulation.