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Old 10-13-2020, 02:30 AM   #51
gisahag
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Default Re: "Phase locking" drones

Jon
To what (if any) extent is the length of the 'tuned' stock dependent on the size of the drone reed? For example would the short Ezeedrone bass require a different sized stock compared to a standard sized Ezeedrone bass reed (or something even chunkier like the Kinnaird bass) due to the different amounts of air they displace from the stock? If so, might that be part of why some makes of drone reeds seem to go better in some makes of pipes than others?


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Old 10-13-2020, 06:39 AM   #52
Jon Snow
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Default Re: "Phase locking" drones

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Originally Posted by gisahag View Post
Jon
To what (if any) extent is the length of the 'tuned' stock dependent on the size of the drone reed? For example would the short Ezeedrone bass require a different sized stock compared to a standard sized Ezeedrone bass reed (or something even chunkier like the Kinnaird bass) due to the different amounts of air they displace from the stock? If so, might that be part of why some makes of drone reeds seem to go better in some makes of pipes than others?
I have not done any tests for this, but I would not expect any change in the stock length based on the size of the drone reed. The tuning is based on the length of the air column, not the volume of air displaced.

I suspect that the reason some reeds work better in some drones than in others has more to do with where the tongue of the reed falls in relation to pressure nodes inside the stock. Here's a short video I made a few years ago which may show this. I had purchased a new Canning bass drone reed, but was unable to get it to work properly. Right about at the tuning point, the rate of change of pitch suddenly increases dramatically, making it virtually impossible to tune. I think there is a pressure node "rolling over" the reed as the drone is tuned.

Gibson pipes like mine are notoriously finicky about bass drone reeds. In my experience, they do not like long tongue reeds unless they are inverted.

I would also note that I sent that video to Ryan and he agreed that his reed would not work in my pipes. There was no issue returning the reed for a full refund.
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Old 10-13-2020, 10:45 AM   #53
Michael Kazmierski Dunn
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Default Re: "Phase locking" drones

In my experience, the stock's vibration has to do to some extent to the length of the reed, i.e. where the airtightness should begin. So for example a Kinnaird tenor with the screw all the way in will have a slightly and I mean only slightly different stock-ringing frequency than one with the tuning screw all the way out. This difference is subtle enough however that it should not affect the drone's ability to lock with the other tenor.
Re: Bass reeds: My stocks on my rep '24 Hendersons are cylindrical and sometimes, when the bridles are set incorrectly on my Canning bass, it tends to behave the same way unless I point the stocks up absolutely verticly. Perhaps a taper with a rounded trumpetlike bell may relieve that problem? I have no idea, not a machinist.
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Old 10-16-2020, 08:29 AM   #54
T.Ackland
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Default Re: "Phase locking" drones

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Originally Posted by el gaitero View Post
Would it be descriptive to call them ‘pulses’...?
Yes, pulses, I had it in my head that drone reeds were not beating reeds, until yesterday.
I applied a very thin film of petroleum jelly onto a short length of 35 mm film stock and passed between the tongue and reed body, thus applying the oily film to the underside of the tongue.
The reed was then mouth blown in a drone and the tongue then bent back to reveal the drone reed seat. This showed a definite witness of the tongue striking the mat black finish of the reed body, but only the tip area, not the whole aperture. Mind you I did not blow hard enough to shut the reed off.
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Old 10-16-2020, 07:20 PM   #55
William McKenzie
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Default Re: "Phase locking" drones

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Originally Posted by T.Ackland View Post
This showed a definite witness of the tongue striking the mat black finish of the reed body, but only the tip area, not the whole aperture. Mind you I did not blow hard enough to shut the reed off.
Interesting Terry! I had not considered this very much. I have always pictured drone reed tongues making full contact in more of either flexible 'rolling' fashion along the reed body aperture or by a rigid 'slapping' action hitting the aperture all at once.

Do you, or maybe could you, snap a photo to show?
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Old 10-17-2020, 10:21 AM   #56
Aaron Shaw
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Default Re: "Phase locking" drones

Just for reference (and yes, it's an uilleann pipe bass drone reed, not highland) here's a link to slow motion video of a drone reed in action.


https://www.youtube.com/watch?v=HoOii_1zGuM



Same folks also did a fascinating video of an uilleann chanter reed in operation.
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Old 10-17-2020, 03:27 PM   #57
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Default Re: "Phase locking" drones

here's my understanding, and please correct me if I'm wrong:
The cycling of the reed is a rssult of the Bernouli principle- the air pssing under the reed tongue is moving faster than the air around it, causing lower airpressure between the tongue and the body of the reed (like the air moving faster over an aircraft wing causing lift). The lower pressure brings the tip of the blade against the body, at which point the low pressure stream cuts off and the blade springs back to start the cycle again. The rate at which the pressure cycle repeats is realted to the leverage of the blade-length and strength play a part here.
Full tone is reached when the pressure/ on/off cycle is in sync with the standing wave resonance of the drone bore.

Any accoustic physicists here to clarify where I'm off base?
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Old 10-17-2020, 04:20 PM   #58
Jim Fogelman
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Default Re: "Phase locking" drones

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Originally Posted by Aaron Shaw View Post
Just for reference (and yes, it's an uilleann pipe bass drone reed, not highland) here's a link to slow motion video of a drone reed in action.


https://www.youtube.com/watch?v=HoOii_1zGuM



Same folks also did a fascinating video of an uilleann chanter reed in operation.
Here’s the video of the chanter reed. https://youtu.be/GCM7kVsYpvI

What I found interesting in this one was how long the reed is open on long notes. You can see some slight pulsing on the low A and soft low D where the reed tips move in a tiny bit but are definitely open. What’s more interesting was the hard low D had uneven pulsing of the reed.

Not wanting to google the terms “soft D” or “hard D” (for hopefully obvious reasons), can someone who also plays uillean pipes explain the difference between the two?
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Old 10-17-2020, 06:06 PM   #59
Patrick McLaurin
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Default Re: "Phase locking" drones

The hard bottom D is a more strident timbre than normal bottom D. They usually have slightly different tuning, at least that's my experience. You activate the hard bottom D by increasing the pressure and playing an A gracenote (equivalent of an E gracenote on highland pipes) to or while on the bottom D.

There is also a "ghost D" was is just a high Eb between the "back D" (high A equivalent) and high E (high B equivalent but played on the bottom hand)
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Old 10-18-2020, 05:45 AM   #60
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Default Re: "Phase locking" drones

The soft D is the "normal" mode of vibration of the reed. The hard D mixes the soft D with the A, which is what gives that characteristic double pulse you see in the video. It usually comes out a little sharper and is considered the preferable sound of the D.


Some chanters will also do a hard E, and my Peter Hunter chanter will do a hard F with a little persuasion.
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