Melodeon.net Forums

Please login or register.

Login with username, password and session length
Advanced search  

News:

Welcome to the new melodeon.net forum

Pages: [1]   Go Down

Author Topic: Modified air button to linearize flow- an experiment  (Read 894 times)

0 Members and 1 Guest are viewing this topic.

hickory-wind

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 261
  • Live in NY USA near the Erie Canal
    • Bellinger's Button Boxes
Modified air button to linearize flow- an experiment
« on: August 08, 2017, 11:36:43 PM »

While playing I’ve often observed that most air buttons have a rather abrupt almost on/off function. If the button travel goes from zero % (closed) to 100% (full open) it seems like by the time the button is at 25% or 30% it is almost the same flow as full open. The chart below crudely represents that with the red curved line. Some tunes need frequent small ‘gulps’ to keep the bellows fairly centered. I have tried to master the ability to open the air button partially while sounding certain notes in each tune to keep the bellows relatively central. I am fairly adept at this point. There is added complexity when playing different boxes as the hole area and pallet travel can vary considerably between instruments.

What if the function could be made more linear? What if 50% actuation gave 50% flow? The goal becomes the green line in the same chart. Well, I have experimented and have come up with a simple (fully reversible) modification that mimics that more linear relationship.

I measured the air hole on my target instrument (DG Trilly) and fabricated a small rectangular puck of expanded polystyrene (Styrofoam is one brand). I made it slightly smaller than the hole so no possibility of rubbing or hanging up on the sides. I then shaped it by hand to gradually change from full area (base of the puck) to zero area (point at the top) as the button is depressed from zero to 100%. The result is picture 2. This worked well but I thought increased slightly the ‘rushing air’ noise while in use. I next removed the puck and using a razor blade cut numerous radial grooves from the base to the peak. This has smoothed out the air flow and made it quieter. I use double sided tape to attach the puck to the pallet leather. A pin tool made centering the puck in the opening easy during assembly (pics 3 & 4).

BellingersButtonBoxes.com
Logged
too many boxes...please buy one, or two, or

hickory-wind

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 261
  • Live in NY USA near the Erie Canal
    • Bellinger's Button Boxes
Re: Modified air button to linearize flow- an experiment
« Reply #1 on: August 08, 2017, 11:39:41 PM »

Since the puck weights almost nothing there is no change in the feel of using the air button. Picture 5 shows the installed grooved puck. Picture 6 show how at full actuation (100%) the peak of the point is about flush with the ‘soundboard’.

At this point I’ve only tested it for a little while but I’m so pleased with the improvement that I have now replicated the modification on my AD Trilly (pic 7).

   Scott

BellingersButtonBoxes.com

Logged
too many boxes...please buy one, or two, or

Steve_freereeder

  • Grumpy old git (sometimes)
  • Content Manager
  • Hero Member
  • ***
  • Offline Offline
  • Posts: 5036
  • MAD is inevitable. Keep Calm and Carry On
    • Lizzie Dripping
Re: Modified air button to linearize flow- an experiment
« Reply #2 on: August 09, 2017, 01:28:35 AM »

Interesting idea!
It's good that you have made the modification reversible by attaching with double-sided sticky tape. My only concern would be that the polystyrene foam might tend to shed small fragments which would be just perfect for getting stuck in a reed tongue and temporarily silencing the reed.

But maybe shedding fragments isn't a problem. Nevertheless, now that you've proved the method is useful and works, perhaps consider replacing the foam with a small block of balsa wood suitably shaped and then varnished.
Logged
Steve
Sheffield, UK.
www.lizziedripping.org.uk

Rob2Hook

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1915
  • Castagnaris, Hohners & Baffetti
Re: Modified air button to linearize flow- an experiment
« Reply #3 on: August 09, 2017, 01:16:59 PM »

I was also worried about flecks of foam getting in the reeds.  I'm sure such a modification would be of great service to beginners, in particular, who will always find control of the air button a difficult skill to acquire.  If the block could be cut with a hot wire it might yield a less friable finish?

On another note - you lucky, lucky guy owning two Trillies!

Rob.
Logged

Kimric Smythe

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 420
    • Smythe's Accordion Center
Re: Modified air button to linearize flow- an experiment
« Reply #4 on: September 06, 2017, 06:16:01 PM »

You are cutting down on turbulent flow as the air coming in from each side is not running into itself. Making a valve that is a truncated conical plug (sorts like a automotive valve) would work even better.
 Removing sharp directional transitions is what you are aiming for.

If you want to nerd out on valve design for cars and the flow changes you can check this out http://garage.grumpysperformance.com/index.php?threads/valve-seat-angles-and-air-flow.8460/.

I have done this sort of thing to anglo concertinas.
Logged
Smythe's Accordion Center
Oakland, California
Fixing broken stuff since 1997

Chris Ryall

  • "doc 3-row"
  • French Interpreter
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7885
  • Wirral UK
    • Chris Ryall
Re: Modified air button to linearize flow- an experiment
« Reply #5 on: September 06, 2017, 08:13:39 PM »

Interesting, good, and controllable air hole flow is very important to me. I "feather" it all the time.

Link cc'd to 21st Century Box thread
Logged
  _       _    _      _ 

Rob2Hook

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1915
  • Castagnaris, Hohners & Baffetti
Re: Modified air button to linearize flow- an experiment
« Reply #6 on: September 06, 2017, 08:27:49 PM »

The analogy with cylinder head flows is just right!  In the long distance past (my youth) I recall being told that music hall performers had the reed chambers of their concertinas packed out with cork so that they could carve a smooth flowing air path to maximise the volume level.

I'f have thought your conical valve would be an ideal project for 3D printing.

Rob.
Logged

Edward Jennings

  • Hero Member
  • *****
  • Online Online
  • Posts: 869
    • "Our Luxor B&B" Luxor life, slice by slice.
Re: Modified air button to linearize flow- an experiment
« Reply #7 on: September 06, 2017, 09:57:46 PM »

High performance petrol engines would have polished ports, and high-lift cams would open the valves faster and farther. Although I've never had the urge to look further into it, I imagine that the valve seating angles wouldn't have that much effect on the volume of air shifted through the ports, given the lightning speed at which they opened or closed. The round valve shape and seating angle coupled with the angle, and size, of the intake and outlet ports and manifolds would only be really relevant when needing the air to swirl into distinct places to maximise combustion or clear the cylinder more quickly.
To get back to the original task of regulating the flow of air actually coming through the air valve, it would seem to me that a spring loaded sliding valve would have been the simplest solution. Either a straightforward slide, like a sliding window, or with a pivot at one end and the air hole at the other, sort of thing. After all, it's the size of the aperture and its "controlability" which is needed, not any fancy air flow; we're just wanting to either dump or gulp air in vaguely measured amounts.
Logged
Edward
Windy Nook.
Hohner 1600 D/G. Hohner 114's in C & G. Hohner 1140 in C. International One Row 2 voice in D. National Band (mainly) 3 stopper in G, low notes with 4th button start, 4 spoon bass, and ergonomic keyboard. 17 button 8 bass, bandoneon tuned, Squirrel with stops for both treble voices in C/F. Plus projects and parts of projects.
http://ourluxorflat.blogspot.co.uk/

george garside

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4125
Re: Modified air button to linearize flow- an experiment
« Reply #8 on: September 06, 2017, 10:15:39 PM »

interesting idea , but would it really do anything that a highly skilled thumb can't do!

george
Logged
author of DG tutor book "DG Melodeon a Crash Course for Beginners".    Available on ebay as a 'buy now' item. Put in melodeon tutor book for full info.

Edward Jennings

  • Hero Member
  • *****
  • Online Online
  • Posts: 869
    • "Our Luxor B&B" Luxor life, slice by slice.
Re: Modified air button to linearize flow- an experiment
« Reply #9 on: September 06, 2017, 10:23:44 PM »

Possibly not, as long as you happen to have a highly skilled thumb knocking about!
Logged
Edward
Windy Nook.
Hohner 1600 D/G. Hohner 114's in C & G. Hohner 1140 in C. International One Row 2 voice in D. National Band (mainly) 3 stopper in G, low notes with 4th button start, 4 spoon bass, and ergonomic keyboard. 17 button 8 bass, bandoneon tuned, Squirrel with stops for both treble voices in C/F. Plus projects and parts of projects.
http://ourluxorflat.blogspot.co.uk/

Steve_freereeder

  • Grumpy old git (sometimes)
  • Content Manager
  • Hero Member
  • ***
  • Offline Offline
  • Posts: 5036
  • MAD is inevitable. Keep Calm and Carry On
    • Lizzie Dripping
Re: Modified air button to linearize flow- an experiment
« Reply #10 on: September 07, 2017, 12:25:37 AM »

we're just wanting to either dump or gulp air in vaguely measured amounts.

Sorry to disagree. 'Dumping and gulping' is not what proper air control is about.

As Chris Ryall has said a few posts earlier, 'feathering' the air button and air flow is important and I teach this to my students. Unlike unisonoric accordion players who mainly use the air button to open and close the bellows at the beginning and end of a playing session, melodeon players should be aiming to optimise both (a) the air in the bellows and (b) the air passing through the reeds simultaneously, at the same time, together, while playing is in progress. The thumb should be constantly hovering or lightly touching the air button, ready to open it very slightly to adjust the bellows spacing. The smaller the cross-sectional area of the bellows and the more reeds that are in play, then the more important this feathering becomes. Playing a one-row four-stop box especially often needs constant adjustment of the air button to avoid running out of bellows space.
Logged
Steve
Sheffield, UK.
www.lizziedripping.org.uk

hickory-wind

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 261
  • Live in NY USA near the Erie Canal
    • Bellinger's Button Boxes
Re: Modified air button to linearize flow- an experiment
« Reply #11 on: September 07, 2017, 01:40:10 AM »

The goal is different here versus an automotive exhaust/intake valve where maximizing flow is the goal. My intent was to linearize the flow so that a half depressed button gives approximately 50% of the flow of a fully depressed button. I have achieved my goal and find my two modified instruments have much more controllable partial opening. I have learned to feather the air valve but on most of my instruments that must occur in the first 10% to 15% of button travel. On the modified boxes it is easier to get the exact flow I want because that feathering zone is broader. Some tunes require partial air button for a long (one directional) phrase to re-center the bellows and I'm finding it easier to accomplish with these now. You are all invited to come and try these out and decide for yourselves if it is an improvement!

Scott

BellingersButtonBoxes.com
Logged
too many boxes...please buy one, or two, or

Kimric Smythe

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 420
    • Smythe's Accordion Center
Re: Modified air button to linearize flow- an experiment
« Reply #12 on: September 07, 2017, 06:33:13 AM »

Sliding and rotary valves would have wear issues since lubrication would not really be possible.
Motion controlled air flow could be achieved with a valve used on early steam cars. I believe the current air valves are used due to simplicity.
Simple things like carefully chamfering the hole the valve covers will smooth out air flow a lot even if you leave the air hole the same size.
Logged
Smythe's Accordion Center
Oakland, California
Fixing broken stuff since 1997

Chris Ryall

  • "doc 3-row"
  • French Interpreter
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7885
  • Wirral UK
    • Chris Ryall
Re: Modified air button to linearize flow- an experiment
« Reply #13 on: September 07, 2017, 07:06:18 AM »

I don't think "linear" air volume flow, relative to switch movement matters at all. As Steve says, in "on the pull", which I use a lot for song, all you want is a fast refill, to gulp/expel air. My Gaillard is superb at this incidentally. Bertrand's valve design is the best I've come across; a major design "plus". I've likened it to a whale's breath out!

In more lyrical play, feathering, or fading notes … the bellows are surely a much greater factor in airvalve use. Basically you get used to the volume transfer characteristics of your box and titrate that against desired sound, and also what you feel in your left arm.

As for valve, I am personally more interested in what it does when 5-10% open, and that that is reliable. I'd also offer that, in play, my thoughts are often more on the air valve than the more busy reed control keys, especially when I'm right end chording. The valve  is the most important button on the instrument. And all the more so on melodeon; as opposed to say: a piano accordion?

Pignol/Milleret's Aire et Geste DVD has a lot to say on all these issues. (English subtitles).
« Last Edit: September 07, 2017, 07:13:27 AM by Chris Ryall »
Logged
  _       _    _      _ 

george garside

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4125
Re: Modified air button to linearize flow- an experiment
« Reply #14 on: September 07, 2017, 10:31:15 AM »

I agree totally that complete command of the air valve is an essential part of good/successful melodeon/ diatonic box playing .  I don't see it as a separate skill ( other than when learning)  but as an integral part of bellows control and much more than a device to ensure you don't run out of air.   eg as an aid to good dynamics  it can be used to drop and increase the volume  in conjunction with alteration to bellows pressure - a bit like a quick and maybe minute dab of an airbrake! 

the air button should never have to be used   on an ''oh shit'' basis if running out of air is imminent!

In other words its use should be a total integrated part of playing  irrespective of the style of air button or bar and the shape and sizeof the air orifice  or the type of music being played etc etc
   

george
Logged
author of DG tutor book "DG Melodeon a Crash Course for Beginners".    Available on ebay as a 'buy now' item. Put in melodeon tutor book for full info.

boxcall

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 814
Re: Modified air button to linearize flow- an experiment
« Reply #15 on: September 07, 2017, 12:19:04 PM »

Possibly not, as long as you happen to have a highly skilled thumb knocking about!
I have one, but mainly use it for hitching a ride ;) well that was a long time ago not so sure about how well it would work now.
I tend to use my palm to control air on my one row and find that I almost never run out of air as the back and forth bellows movement doesn't require much use, at least for me. I did use it more when I started out.
 My D/C# box does require more "highly skilled thumb" use, more so on tunes/reels played on the pull where there's not much time and notes on the push to bring them in again. I'm still learning to control the beast, it's LLMM.
Logged
Hohner 1040 C, Beltuna one row four stop D, O'Byrne Dewitt/ Baldoni bros. D/C#, "pepperpot" one row D

george garside

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4125
Re: Modified air button to linearize flow- an experiment
« Reply #16 on: September 07, 2017, 01:36:49 PM »

just for the sake of academic research or playing silly buggers if you prefer,  I have on a one row hohner 4 stop in air hungry G lower octave played winster gallop, Jamie allen, Scotland the brave and girl with the blue dress on   full volume + um pa bass without break between tunes  and absolutely no use of the air button (starting with bellows 7 inches open)

george ;)

 
Logged
author of DG tutor book "DG Melodeon a Crash Course for Beginners".    Available on ebay as a 'buy now' item. Put in melodeon tutor book for full info.

Edward Jennings

  • Hero Member
  • *****
  • Online Online
  • Posts: 869
    • "Our Luxor B&B" Luxor life, slice by slice.
Re: Modified air button to linearize flow- an experiment
« Reply #17 on: September 07, 2017, 02:04:12 PM »

"Sorry to disagree. 'Dumping and gulping' is not what proper air control is about."

Granted! But that is exactly what the actual valve is about. How far open it is, and when, is surely down to the player, no matter which design is used. All this talk of "feathering" or "volume control" or whatever, is entirely at the player's thumb-tip.

As far as the wearing of sliding components goes, I dare say that PTFE (or something, I don't know!) surfaces could minimise that, if someone clever took hold of it.

Mind you, I'm not denigrating the OP's idea, it's just all the scientific stuff which I think is unnecessary for the purpose of helping melodeon players via giving the reeds a bit more or less air to play with. "Overthinking", I'd call it.
Logged
Edward
Windy Nook.
Hohner 1600 D/G. Hohner 114's in C & G. Hohner 1140 in C. International One Row 2 voice in D. National Band (mainly) 3 stopper in G, low notes with 4th button start, 4 spoon bass, and ergonomic keyboard. 17 button 8 bass, bandoneon tuned, Squirrel with stops for both treble voices in C/F. Plus projects and parts of projects.
http://ourluxorflat.blogspot.co.uk/

Rob2Hook

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1915
  • Castagnaris, Hohners & Baffetti
Re: Modified air button to linearize flow- an experiment
« Reply #18 on: September 19, 2017, 03:32:24 PM »

Trouble is, even if you were to use PTFE, a lifting valve is used because the only friction involved is in the mechanism pivots.  Any rotary or sliding valve could reasonably be expected to have some friction to overcome just to get it moving - over and above that of the mechanism.  That would make it more difficult to control for feathering.

The only improvement on the conical version shown would be to make a matching conical (cup) seat for it, but anyone who has used conical (albeit rotary) seacocks will know that it takes very little applied pressure to make the plug stick in the seat - there is too much surface area in contact.  The OP's design overcomes this by using the original flat seat for the actual seal whilst the cone modifies the flow characteristics once open.  I can't think of another equal or better configuration.

Rob.
Logged

hickory-wind

  • Respected Sage
  • ****
  • Offline Offline
  • Posts: 261
  • Live in NY USA near the Erie Canal
    • Bellinger's Button Boxes
Re: Modified air button to linearize flow- an experiment
« Reply #19 on: September 19, 2017, 05:36:56 PM »

Thanks Rob.

I'm 6 weeks in now and like the improvement so much that each time I open up another of my personal boxes I will do this modification. I like Steve's suggestion of balsa wood and probably would have used that to begin with if I had some laying around. The polystyrene is working fine and not shedding and very easy and quick to work with. I'm going to try a thin layer of lacquer or similar as a sealer next time unless I go out and purchase some balsa.

Scott

BellingersButtonBoxes.com
Logged
too many boxes...please buy one, or two, or
Pages: [1]   Go Up
 


Melodeon.net - (c) Theo Gibb; Clive Williams 2010. The access and use of this website and forum featuring these terms and conditions constitutes your acceptance of these terms and conditions.