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jim cook
Jeff G posted the tip of undercutting a hole to make it sharper, he's had (and others too) some other great tips on how to tweak a flute to make it sound better, but they're scattered throughout the different threads on the forum. i thought it'd be good to have a thread for the makers/more experienced tweakers to post tips that will help people fine tune lesser made flutes.
Barry G
QUOTE(jim cook @ Mar 25 2009, 08:39 AM) *
Jeff G posted the tip of undercutting a hole to make it sharper, he's had (and others too) some other great tips on how to tweak a flute to make it sound better, but they're scattered throughout the different threads on the forum. i thought it'd be good to have a thread for the makers/more experienced tweakers to post tips that will help people fine tune lesser made flutes.


Jim, using a spacer allows for much more tweaking and flexibility of the crispness/responsiveness, and playing in the upper octave than if you carved a flue and TSH.

Barry G
Jimbo
From my re-tuning thread:
subject - undercutting finger holes.
QUOTE(Mike @ Mar 25 2009, 11:08 AM) *
Technically, yes, the smallest diameter of the opening does not get bigger with undercutting. But since the bottom of the finger hole IS bigger when you undercut, the average diameter of the finger hole does get larger. So undercutting the hole to the north will effectively enlarge the hole with a bias toward the north.

Mike


So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?
Jimbo
Another question:

I've got a plains style flute in F# that sounds raspy. All the notes hit real close on my tuner, but it sounds buzzy or raspy. What can be done to smooth out the sound, short of getting a woodlands style. tongue.gif

FYI, A friend has an older F# by the same maker, but his sounds smooth as silk.
Anthony Lee
QUOTE(Jimbo @ Mar 25 2009, 09:39 AM) *
Another question:

I've got a plains style flute in F# that sounds raspy. All the notes hit real close on my tuner, but it sounds buzzy or raspy. What can be done to smooth out the sound, short of getting a woodlands style. tongue.gif

FYI, A friend has an older F# by the same maker, but his sounds smooth as silk.


Sometimes a flute will sound buzzy or raspy due to fuzzies hanging around inside the bore. Get the sound hole under a light, and sight down the bore. If you see "Hanging Chads" clean them out. You can do this with a piece of fine sandpaper rolled into a tube and work carefully inside the finger holes. If needed a light sanding on the inside of the bore will also clear them out.

Another reason could be something in the flue of the flute. check to make sure it is nice and clean also. A fuzzy flute plays fuzzy a smooth plays......
Barry G
QUOTE(Jimbo @ Mar 25 2009, 09:06 AM) *
From my re-tuning thread:
subject - undercutting finger holes.
So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?


Generally no. Going south simply enlargens the hole thus allowing for more volume, but going south is not the exact opposite of going north towards the TSH. A good example of what I'm saying is, I'm sure you've seen flutes with the four tuning holes actually having a channel cut about 2" to a second hole or a slit from the tuning hole to another hole several inches down. If the logic was going south flattens the fundamental then these flutes with the slit would be way off. So, going south from the tuning hole or any other for that matter has little effect other then volumn. I'd like to hear from other makers about going south and its effect.

Barry G
Jeff G
QUOTE(Jimbo @ Mar 25 2009, 01:06 PM) *
From my re-tuning thread:
subject - undercutting finger holes.


So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?


nope....You would have to fill in the north edge then file the south.
Mike
QUOTE(Jimbo @ Mar 25 2009, 09:06 AM) *
From my re-tuning thread:
subject - undercutting finger holes.
So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?


Like Jeff said.

If you move a hole of the same diameter down the bore, then the pitch will flatten. That usually means means plug & re-drill, or put it lower on the next flute. If you undercut to the south, then you are also making the hole bigger, which will sharpen the note (unless the hole is already very large, in which case it may do nothing to the pitch--but it won't flatten it).

Mike
Russ Wolf
QUOTE(Jimbo @ Mar 25 2009, 09:06 AM) *
From my re-tuning thread:
subject - undercutting finger holes.
So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?

Undercutting a hole to the South sharpens the basic note but not as quickly as going to the North. It also has the effect of sharpening the cross fingered note associated with that playing hole. When you undercut to the South it sharpens the cross fingered note more than the basic note, but it still sharpens the basic note. Undercutting North is the opposite.
If you are not concerned about the cross fingered notes, undercut to the North for the greatest effect. Russ
Jimbo
This is going to be a good thread. I've already tripled or quadrupled my knowledge about retuning. biggrin.gif

As for that raspy F# of mine, the bore is pretty rough. It's rougher than any of my other flutes. I'm going to rig some sort of flap sander on a long shaft, hook it to my power drill and see if I can't slick it up a little in there. The flute plays 10-15 cents sharp for me, so I don't think a few thousandths increase in bore diameter will throw the tuning too far off. I plan to swab the bore with Polyurethane finish after I get it slicked up.
Pipyr
Hey Jim (and anyone else)...is "raspy" always a "bad" thing? I have a couple flutes that have some "texture" (as I call it) to their voice and I enjoy them as much as my super clear flutes, for different reasons. They also tend to be the flutes that friends like best when they are first introduced to the NAF.

So, if all else is equal, will a flute with some "raspiness" in its voice always be considered a lesser flute than a crystal clear one? It won't change my opinion on my flutes...I am just curious if this is generally something to be avoided or fixed in a flute? Or is it just a personal taste thing, where some makers strive to keep that texture and others try to get rid of it?
Just Jim
QUOTE(Pipyr @ Mar 25 2009, 08:04 PM) *
Hey Jim (and anyone else)...is "raspy" always a "bad" thing? I have a couple flutes that have some "texture" (as I call it) to their voice and I enjoy them as much as my super clear flutes, for different reasons. They also tend to be the flutes that friends like best when they are first introduced to the NAF.

So, if all else is equal, will a flute with some "raspiness" in its voice always be considered a lesser flute than a crystal clear one? It won't change my opinion on my flutes...I am just curious if this is generally something to be avoided or fixed in a flute? Or is it just a personal taste thing, where some makers strive to keep that texture and others try to get rid of it?


The Ahabi Rabbi flute I bought at the Green Frog Moon festival has a sort of buzzing sound to it... I guess raspiness is as good a word as any. I thought it was done that way on purpose.. but now I have to wonder as well.
Still, I agree with you, I bought the flute because I liked the sound, so I don't think if it was considered a "lesser" flute I'd try and change it.
pvanheuklom
QUOTE(Pipyr @ Mar 25 2009, 04:04 PM) *
Hey Jim (and anyone else)...is "raspy" always a "bad" thing? I have a couple flutes that have some "texture" (as I call it) to their voice and I enjoy them as much as my super clear flutes, for different reasons. They also tend to be the flutes that friends like best when they are first introduced to the NAF.

So, if all else is equal, will a flute with some "raspiness" in its voice always be considered a lesser flute than a crystal clear one? It won't change my opinion on my flutes...I am just curious if this is generally something to be avoided or fixed in a flute? Or is it just a personal taste thing, where some makers strive to keep that texture and others try to get rid of it?

I guess it depends on how raspy or buzzy we're talking about. Some woods I believe, redwood in particular, can have a bit of buzziness to them, but I think it's part of the character of the flute. One that I have--an old-growth redwood F by JP Gomez--is a fantastic player.
Anthony Lee
QUOTE(Pipyr @ Mar 25 2009, 04:04 PM) *
Hey Jim (and anyone else)...is "raspy" always a "bad" thing? I have a couple flutes that have some "texture" (as I call it) to their voice and I enjoy them as much as my super clear flutes, for different reasons. They also tend to be the flutes that friends like best when they are first introduced to the NAF.

So, if all else is equal, will a flute with some "raspiness" in its voice always be considered a lesser flute than a crystal clear one? It won't change my opinion on my flutes...I am just curious if this is generally something to be avoided or fixed in a flute? Or is it just a personal taste thing, where some makers strive to keep that texture and others try to get rid of it?


I would agree, Raspy or buzzy can be a good character in a flutes voice. I have a few myself. One in particular that I really enjoy the sound of. I think once again it is the voice that speaks to you. Some like it some don't. Some sound great "buzzy" some don't.
greybeard
The best advice I could give is "Before you tweak, Talk to the original Maker" . They would have the best understanding of the tuning and voicing. What you are looking to do may or may not be readily achievable.

A couple little well placed file strokes can make a considerable difference. Conversely, a couple ill placed or overly agressive strokes can do the opposite. Nothing at all wrong with cleaning up a couple little fuzzies though but I wouldn't advise messing with the airway.
Just Jim
Yeah, I would definitly call Michael before I started screwing with a flute's tuning myself!

As for my Ahabi Rabbi, it's Bolivian Rosewood, I think. It's early and I haven't had enough coffee yet! hehe.
It feels VERY dense and hard to the touch compaired to my others, which are maple, cherry or walnut, but that may just be the finish.

But with such a distinct "arabian" sound, if you will, I think the buzzing fits the tone; it just makes it a little weirder than it already is... which to me is a good thing!!!
Spirit of the Woods
QUOTE(Jimbo @ Mar 25 2009, 09:06 AM) *
From my re-tuning thread:
subject - undercutting finger holes.
So can we assume that undercutting the hole to the south, or foot of the flute will have the opposite effect and actually flatten the note a bit?



No Jimbo, wheather you underscore it north, south, east or west it will sharpen the flute. Basically anytime you remove wood from the flute it is going to sharpen it. Just sanding the exterior of the flute will sharpen it.
Spirit of the Woods
QUOTE(Jimbo @ Mar 25 2009, 09:39 AM) *
Another question:

I've got a plains style flute in F# that sounds raspy. All the notes hit real close on my tuner, but it sounds buzzy or raspy. What can be done to smooth out the sound, short of getting a woodlands style. tongue.gif

FYI, A friend has an older F# by the same maker, but his sounds smooth as silk.



This kind of depends.... There are several things actually like flatening the splitting edge, if there is an angle cut at the front of the block some of this could be reduced, depth of the flue could be checked, etc. Kind of like working on a car when you do something like this. Many things to consider and check before you actually do anything.
jim cook
what would be the best method to flatten a hole a few cents?
Mike
QUOTE(jim cook @ Mar 26 2009, 11:29 AM) *
what would be the best method to flatten a hole a few cents?


I would go with building up a film of lacquer, epoxy, or some other material on the inside rim of the finger hole. This will constrict the hole and flatten it.
Jeff G
QUOTE(Mike @ Mar 26 2009, 03:48 PM) *
I would go with building up a film of lacquer, epoxy, or some other material on the inside rim of the finger hole. This will constrict the hole and flatten it.


Thats what I have done. A little super glue.. in extreme cases, clear nail polish builds up pretty quickly and adheres very well.
Spirit of the Woods
QUOTE(Mike @ Mar 26 2009, 11:48 AM) *
I would go with building up a film of lacquer, epoxy, or some other material on the inside rim of the finger hole. This will constrict the hole and flatten it.


Yep!
Jimbo
QUOTE(Jeff G @ Mar 26 2009, 03:43 PM) *
Thats what I have done. A little super glue.. in extreme cases, clear nail polish builds up pretty quickly and adheres very well.



I used gel type super glue to build up the first hole in my mid-D flute so it was not so sharp. Now, it plays all notes very close on pitch for me.
Jimbo
QUOTE(Spirit of the Woods @ Mar 26 2009, 02:10 PM) *
This kind of depends.... There are several things actually like flatening the splitting edge, if there is an angle cut at the front of the block some of this could be reduced, depth of the flue could be checked, etc. Kind of like working on a car when you do something like this. Many things to consider and check before you actually do anything.


I'm not certain what you are telling me here about flattening the splitting edge. Are you describing the bevel on the front edge of the TSH? And by flattening, do you nean removing a little material so that it is not a sharp knife-edge bevel?

This is a plains style flute with the flue in the block. The front edge of the block is square to the base and is flat with no chimney surrounding the TSH.
Jeff G
QUOTE(Jimbo @ Mar 27 2009, 12:59 PM) *
I'm not certain what you are telling me here about flattening the splitting edge. Are you describing the bevel on the front edge of the TSH? And by flattening, do you nean removing a little material so that it is not a sharp knife-edge bevel?

This is a plains style flute with the flue in the block. The front edge of the block is square to the base and is flat with no chimney surrounding the TSH.


Making the cutting edge less sharp. They can be too sharp edged..
Jimbo
QUOTE(Jeff G @ Mar 27 2009, 12:43 PM) *
Making the cutting edge less sharp. They can be too sharp edged..



Could be the problem. This one of mine is knife edged. If it were metal, it would be sharp enough to cut.
greybeard
QUOTE(Jimbo @ Mar 27 2009, 10:03 AM) *
Could be the problem. This one of mine is knife edged. If it were metal, it would be sharp enough to cut.


Just a word of warning, as you flatten that cutting edge you will inevitably deepen the TSH slightly which will sharpen the flute across the board. Also, there is a tipping point where it will become very windy and may require some other actions to counteract. So, unless it is really intolerable the way it is, or you are willing to risk wrecking it all together and/or just want to consider it to be a learning experience.... You might just want to leave it as is and gift it to another when you can replace it with a flute that more suits your needs. smile.gif


Jeff G
QUOTE(greybeard @ Mar 27 2009, 02:57 PM) *
Just a word of warning, as you flatten that cutting edge you will inevitably deepen the TSH slightly which will sharpen the flute across the board. Also, there is a tipping point where it will become very windy and may require some other actions to counteract. So, unless it is really intolerable the way it is, or you are willing to risk wrecking it all together and/or just want to consider it to be a learning experience.... You might just want to leave it as is and gift it to another when you can replace it with a flute that more suits your needs. smile.gif


If you do tackle it.. work very slowly. You don't blunt it much.. just a tiny bit.
Jimbo
QUOTE(Jeff G @ Mar 27 2009, 02:54 PM) *
If you do tackle it.. work very slowly. You don't blunt it much.. just a tiny bit.



I've tried it, and it was a success. I put some fine grit sticky back sandpaper on a 1/4" gouge and took a couple of light strokes, put the block back on and tried again. Better..... A couple more strokes did it and I'm more satisfied. The raspyness is probably reduced 50%. I know that is subjective, but my wife agrees that is sounds better.

fyi: The flattened edge is probably no more than .015 - .020 wide. Same for the increase in front to back size of the TSH - no more than .020-.030". It did raise the sharpness across the scale a small amount like you said it would. A little polishing of the very rough bore should flatten it back a bit, if I understand the design theory correctly.

I know, I know - a little bit goes a long way. smile.gif
Mike
QUOTE(Jimbo @ Mar 27 2009, 01:10 PM) *
I've tried it, and it was a success. ...


Jimbo,

Thanks for the feedback! Usually, when someone asks, we rarely hear back whether the suggestion worked or not. The details in your reprts are very useful for folks watching on the sidelines. It makes this thread more like a practical demonstration.

Great thread!

Mike
Jimbo
QUOTE(Mike @ Mar 27 2009, 07:18 PM) *
Jimbo,

Thanks for the feedback! Usually, when someone asks, we rarely hear back whether the suggestion worked or not. The details in your reprts are very useful for folks watching on the sidelines. It makes this thread more like a practical demonstration.

Great thread!

Mike



Well, I think that the knowledge is something that could benefit every flute player. Everyone has a different playing style and breath control. A flute maker will tune a flute using his/her own breath. The person who buys the flute may have a different breathing style when playing, so they may play that flute slightly flat or sharp - maybe even quite a bit flat or sharp. Maybe they can learn to compensate and change their breath for that particular flute, and maybe they would prefer to change the flute to match their style.

Most well-known flute makers do a great job on most of the flutes they make. If they didn't, they wouldn't be so well known. smile.gif

Still, sometimes a flute will get shipped with an out of tune note. It may be just a few cents off, but it may be enough to bother someone with a very good ear. Knowing how to apply a simple correction to the problem can save a lot of time and money in sending the flute back & forth to the maker.

Tweaking the tuning on your flutes may not be for everyone. I certainly wouldn't recommend it for someone with no mechanical aptitude or poor skill with hand tools. But, otoh, if someone has the tools and is already a fair craftsman in other fields, why not? If you are a detail oriented person, then I say go for it!

Jimbo
Ok, another question topic:

What is the relationship between bore diameter and length of the slow air chamber to pitch?

Edit: I got my terminology mixed up. I meant to ask about the relationship between the sound chamber diameter & length to pitch.

If I understand correctly, chamber length is measured from the back edge of the TSH to the foot, or to the nearest edge of any tuning holes (aka: four winds holes) placed near the foot.

If a flute with tuning holes plays very flat on the fundamental note, what are options to sharpen it and bring it up to tune? Assume that enlarging or moving the tuning holes is not an option? Let's also say that modifying the TSH is not an option.

Is it hopeless?

What about modifying the bore diameter?
Mike
QUOTE(Jimbo @ Apr 1 2009, 10:06 AM) *
Ok, another question topic:

What is the relationship between bore diameter and length of the slow air chamber to pitch?


SAC dia and length is not tied to the pitch, but will affect response.

QUOTE
If I understand correctly, chamber length is measured from the back edge of the TSH to the foot, or to the nearest edge of any tuning holes (aka: four winds holes) placed near the foot.


If a flute with tuning holes plays very flat on the fundamental note, what are options to sharpen it and bring it up to tune? Assume that enlarging or moving the tuning holes is not an option? Let's also say that modifying the TSH is not an option.

Is it hopeless?

What about modifying the bore diameter?


Challenge questions--cool!

Are all the other notes in tune? If so, I assume you want to keep them in tune.

Mike
greybeard
QUOTE(Jimbo @ Apr 1 2009, 10:06 AM) *
Ok, another question topic:

What is the relationship between bore diameter and length of the slow air chamber to pitch?

No relationship between SAC length and pitch. That will effect other playing characteristics but it is the TSH forward toward the foot of the flute that determines pitch

If I understand correctly, chamber length is measured from the back edge of the TSH to the foot, or to the nearest edge of any tuning holes (aka: four winds holes) placed near the foot.

The Slow air camber is the primary chamber of the flute from the blow hole to the exit leading to the flue. The Bore or secondary chamber is from the wall to the foot of the flute. Tuning holes effectively terminate the bore.

If a flute with tuning holes plays very flat on the fundamental note, what are options to sharpen it and bring it up to tune? Assume that enlarging or moving the tuning holes is not an option? Let's also say that modifying the TSH is not an option.

Depends on how much you need to sharpen. Moving thr block back slightly will sharpen. If it need to be sharpened beyond the tuning capacity of the block movement the way to do that would be to shorten the bore. In the case of a flute with tuning holes you would enlarge the holes or extend them closer to the TSH

Is it hopeless?

Define how you mean hopeless, is the flute totally unplayable now?

What about modifying the bore diameter?

Don't go there as you would change more that the fundamental


Jim, you might want to pick up one or more of Lew Paxton Prices books from Oregon Flute Store. I'm still waiting for my signed copy of Mikes book wink.gif
Jimbo
QUOTE(greybeard @ Apr 1 2009, 03:53 PM) *
Jim, you might want to pick up one or more of Lew Paxton Prices books from Oregon Flute Store. I'm still waiting for my signed copy of Mikes book wink.gif



Yeah, If I'm going to continue down this DIY path, I should probably pick up some books on the subject. smile.gif

I edited my post. I used the wrong term and meant to ask about the sound chamber.

I read that, given a particular bore, a longer sound chamber means a lower pitch. Opening the finger holes effectively shortens the length of the sound chamber and raises the pitch. I may be totally wrong, but to my thinking, this goes along with finger hole size - a larger diameter finger hole has more influence on effective length and sharpens a note.

Wouldn't the inverse be true and if the length is fixed, increasing the bore diameter would have the same sharpening effect on the fundamental as shortening a smaller bore flute? Finger hole area/volume would be smaller in relation to bore area/volume, so I would think that simply increasing bore would sharpen the fundamental (all holes closed) and flatten all other notes.
greybeard
Think of it as water through a pipe. Assume that the volume (flow rate) is fixed. If you constrict the inner dia the water accelerates and pressure increases; increase dia. and it slows down and pressure decreases.

A faster moving air column vibrates at a higher frequency, slower, lower.
Jimbo
QUOTE(greybeard @ Apr 1 2009, 07:15 PM) *
Think of it as water through a pipe. Assume that the volume (flow rate) is fixed. If you constrict the inner dia the water accelerates and pressure increases; increase dia. and it slows down and pressure decreases.

A faster moving air column vibrates at a higher frequency, slower, lower.


Hmmm....

I've already sanded quite a bit on this particular flute's bore and saw a corresponding increase in pitch. I've got the bore nearly as smooth as glass. It's unlikely that I've changed the diameter more than a few thousands as I'm using 220 grit sandpaper. It's possible I'm seeing an increase in pitch due to a more efficient air flow with less system loss and increased velocity in the sound chamber.

Ya know, I set my tuner to 436 Hz. The fundamental is almost perfectly on pitch for Verdi tuning! biggrin.gif Maybe I should just retune the rest of it to Verdi tuning!!! tongue.gif
Mike
QUOTE(Jimbo @ Apr 1 2009, 04:08 PM) *
increasing the bore diameter would have the same sharpening effect on the fundamental as shortening a smaller bore flute? Finger hole area/volume would be smaller in relation to bore area/volume, so I would think that simply increasing bore would sharpen the fundamental (all holes closed) and flatten all other notes.


The basic answer is the length has everything to do with it, not the diameter.

That being said, there are some "second-order effects" that have the appearance of changing the pitch by increasing the bore, and some caveats to throw in.

The finger holes are one of those second-order effects - if you increase the bore uniformly along the entire length, and leave the finger holes (and TSH) the same, then the holes will be flatter because the the ratio of the hole-to-bore diameter is smaller. As for the fundamental, the foot will be bigger, so the end correction will be slightly longer (k1), which will make the fundamental slightly flatter.

If you look closer at how the bore works on the fundamental, you find that increasing the diameter near the ends will sharpen the pitch. That's where the analogy of water flowing in a pipe "holds water" (pun intended...). That's because the ends are at acoustic flow antinodes. Lew Paxton Price talks about this in his books, and in this zone those equations work well. On the other hand, if you increase the bore diameter in the middle where the flow node is, the flow is minimal, and the pressure effects dominate instead (the flow node is also the pressure antinode). Near the pressure antinode, or in the "pressure zone" the springiness of the air is what matters. A bigger bore has a "softer" springiness in the air column, so it takes a little longer to transmit the pressure wave, so the pitch flattens.

The sharpening in the flow zones balance the flattening in the pressure zones, so if you enlarge the bore everywhere, you are only affecting the end corrections at the openings (i.e., those second-order effects). But if you are selective in where you enlarge the bore, you could make some notes to go sharp and some to go flat, depending on whether the enlargement is in a pressure zone or a flow zone for that particular note.

So, to answer your original question (assuming you only want to change the fundamental), you could try sanding just in the vicinity of the direction holes to increase the diameter in the fundamental's flow zone. But don't make the walls thinner AT THE DIRECTION HOLES because that will sharpen the pitch due to the holes. I recommend trying the following inverse experiment first:
- make a ring of paper or cork or fun foam (craft supplies) with the outside diameter the same as the inside diameter of the bore
- make the ring about an inch or so long and about 1/16 thick around the perimiter
- slide the ring up the bore to where you plan to remove material
- play all the notes on the flute and record how much they changed compared to without the ring

What this does is create a bore constriction instead of a dilation. The effect is the opposite of what would happen if you removed that much material. If you find that the fundamental flattens, but the rest of the notes hardly change, then sanding in that spot will sharpen the fundamental without disturbing the other notes. If other notes DO change in the experiment, then you can expect the same relative change in the opposite direction. It's a good way to test any planned bore perturbations before doing anything permanent. Keep in mind that 1/16 inch is a LARGE amount of material, so the effect will be amplified -- when you actually remove material you will do so very slowly and you can check your progress often.

Mike
Jimbo
QUOTE(Mike @ Apr 2 2009, 06:06 PM) *
The basic answer is the length has everything to do with it, not the diameter.

That being said, there are some "second-order effects" that have the appearance of changing the pitch by increasing the bore, and some caveats to throw in.


So, to answer your original question (assuming you only want to change the fundamental), you could try sanding just in the vicinity of the direction holes to increase the diameter in the fundamental's flow zone. But don't make the walls thinner AT THE DIRECTION HOLES because that will sharpen the pitch due to the holes. I recommend trying the following inverse experiment first:
- make a ring of paper or cork or fun foam (craft supplies) with the outside diameter the same as the inside diameter of the bore
- make the ring about an inch or so long and about 1/16 thick around the perimiter
- slide the ring up the bore to where you plan to remove material
- play all the notes on the flute and record how much they changed compared to without the ring

What this does is create a bore constriction instead of a dilation. The effect is the opposite of what would happen if you removed that much material. If you find that the fundamental flattens, but the rest of the notes hardly change, then sanding in that spot will sharpen the fundamental without disturbing the other notes. If other notes DO change in the experiment, then you can expect the same relative change in the opposite direction. It's a good way to test any planned bore perturbations before doing anything permanent. Keep in mind that 1/16 inch is a LARGE amount of material, so the effect will be amplified -- when you actually remove material you will do so very slowly and you can check your progress often.

Mike


Thanks Mike. I will try this.
Jimbo
Status report:

I tried Mike's tip of using a cylinder of paper. I rolled up a 1" wide piece of construction paper to probaby 3/32" thickness and inserted it in the end of the sound chamber and pushed it to about 1/2: above the tuning holes.

The fundamental pitch immediately dropped from a high C about 20 cents flat to a B about 10 cents flat. The other notes were less affected. The further I pushed the restriction toward the first hole (D#) the sharper it got, but still nowhere near the high C it is supposed to be.

Using the paper cylinder to cover about 1/4 of the tuning holes toward the foot brought the fundamental to perfect pitch, confirming my suspicions that the tuning holes were drilled too close to the foot in the first place.

So, a little more careful sanding of the bore a half inch above the tuning holes should bring the fundamental into tune. I'm probably going to need to build up a couple of the upper holes that are too sharp.
Mike
QUOTE(Jimbo @ Apr 3 2009, 02:01 PM) *
Status report:

I tried Mike's tip of using a cylinder of paper. I rolled up a 1" wide piece of construction paper to probaby 3/32" thickness and inserted it in the end of the sound chamber and pushed it to about 1/2: above the tuning holes.

The fundamental pitch immediately dropped from a high C about 20 cents flat to a B about 10 cents flat. The other notes were less affected. The further I pushed the restriction toward the first hole (D#) the sharper it got, but still nowhere near the high C it is supposed to be.

Using the paper cylinder to cover about 1/4 of the tuning holes toward the foot brought the fundamental to perfect pitch, confirming my suspicions that the tuning holes were drilled too close to the foot in the first place.

So, a little more careful sanding of the bore a half inch above the tuning holes should bring the fundamental into tune. I'm probably going to need to build up a couple of the upper holes that are too sharp.


Just curious what happens with the paper tube just below the tuning holes? I'm not sure I get the part about covering 1/4 of the tuning holes with the paper; I would expect the pitch would go way flat with the constriction AND the smaller tuning holes. That's why I'm curious about what happens below the tuning holes.

For grins, try sliding it up to the middle of the bore and see what happens to the fundamental - you should see it get sharp. Push it farther and it will flatten again as you get close to the TSH.

Mike
Jeff G
QUOTE(Jimbo @ Apr 3 2009, 06:01 PM) *
Status report:

I tried Mike's tip of using a cylinder of paper. I rolled up a 1" wide piece of construction paper to probaby 3/32" thickness and inserted it in the end of the sound chamber and pushed it to about 1/2: above the tuning holes.

The fundamental pitch immediately dropped from a high C about 20 cents flat to a B about 10 cents flat. The other notes were less affected. The further I pushed the restriction toward the first hole (D#) the sharper it got, but still nowhere near the high C it is supposed to be.

Using the paper cylinder to cover about 1/4 of the tuning holes toward the foot brought the fundamental to perfect pitch, confirming my suspicions that the tuning holes were drilled too close to the foot in the first place.

So, a little more careful sanding of the bore a half inch above the tuning holes should bring the fundamental into tune. I'm probably going to need to build up a couple of the upper holes that are too sharp.

Did I post this already???

Another way to sharpen the fundamental.. if the flute does not have tuning holes at the end.. You can enlarge the bore at the end of flute. If effect, that shortens the flute without cutting it off. Use a dremel and sanding drum and you can slowly thin the end of the flute, tapering the sanded area so it doesn't really show. Work VERY slowly as this quickly affects the tuning.
Jimbo
QUOTE(Mike @ Apr 3 2009, 05:38 PM) *
Just curious what happens with the paper tube just below the tuning holes? I'm not sure I get the part about covering 1/4 of the tuning holes with the paper; I would expect the pitch would go way flat with the constriction AND the smaller tuning holes. That's why I'm curious about what happens below the tuning holes.

For grins, try sliding it up to the middle of the bore and see what happens to the fundamental - you should see it get sharp. Push it farther and it will flatten again as you get close to the TSH.

Mike


With the paper restriction between the tuning holes and foot, there is no effect on pitch.

With the tuning holes completely closed, it drops flat a full note.

The restriction placement covering the tuning holes is very sensitive. A little too high, covering too much of the tuning hole, and it goes flat. A little too close to the foot, opening the holes too much, and it goes flat.
Mike
QUOTE(Jimbo @ Apr 3 2009, 04:42 PM) *
With the paper restriction between the tuning holes and foot, there is no effect on pitch.

With the tuning holes completely closed, it drops flat a full note.

The restriction placement covering the tuning holes is very sensitive. A little too high, covering too much of the tuning hole, and it goes flat. A little too close to the foot, opening the holes too much, and it goes flat.



Great - thanks. I've never looked at what happens below the tuning holes before, so this is a good data point.

Mike
Jimbo
QUOTE(Mike @ Apr 4 2009, 11:53 AM) *
Great - thanks. I've never looked at what happens below the tuning holes before, so this is a good data point.

Mike



Success!

The sanding is finished and I now have a flute that plays the fundamental & second note on pitch without having to blow until my eyes bug out. I resealed the bore with poly and tomorrow will adjust down the sharpness of some of the upper notes with some black nail polish dabbed around the finger holes that are playing sharp.

nokeys
I know the answer is somewhere on here just can't find it.... I recently picked up an older flute that was not well cared for. Don't think the bird had even evey been removed. Poor flute was dryer than dust. Anywho after a good cleaning and oiling the voice is buzzy, however if I put a different bird on it clears right up. So I know I need to sand the bottom of the bird but with what grit? And didn't someone say just one direction? Help! blink.gif

Thanks! Penni
Hawk
Penni have you first considered if the flute was meant to be buzzy or not? Some flutes are meant to be that way. Do you know who made it or when it was made? Is it very old~made before the effort to standardize them began?

You mentioned that using a different bird gave a different result. Are both birds built the same? If not then it may not be the bottom of the bird that is causing the buzziness. Can you post pics of the flute/bird?

I would begin sanding with something superfine such as 320 or maybe 400 grit. This will remove very little from the bird. After about 4-6 strokes place the sadlle on the flute and listen. Keep doing this until you get the desired results but I would go very slowly....
greybeard
QUOTE(Hawk @ Apr 29 2009, 06:46 PM) *
I would begin sanding with something superfine such as 320 or maybe 400 grit. This will remove very little from the bird. After about 4-6 strokes place the sadlle on the flute and listen. Keep doing this until you get the desired results but I would go very slowly....


If you do sand the bottom of the bird put a piece of sandpaper flat on a hard surface, glass, hard countertop, ect. Place the bird firmly on the paper with the sound hole end facing you. Sand by drawing toward you, one direction only. Never back and forth sand as this usually leads to rounded edges and a rocking bird.


nokeys
Thanks guys! I knew I had seen this advice somewhere! I should clarify. The flute is probably only old in terms of my collection! laugh.gif There is actaully no date and heck it could be just a couple of years old but left unused in the sun for it's whole life. The flute is a Russ Venable Diatonic D and I have an Email into him -just haven't heard back and getting antsy to doctor this baby back to it's true voice.

Actually Hawk, my favorite flute is a little cedar A that vibrates "buzzes" it's little heart out tongue.gif \
Hawk
Hi Penni~one more thought...
A couple of the flutes in my collection when not played will also get very raspy/airy. I find that if I play them for a while 15-20 minutes at a time over the course of a couple days the issue resolves itself. I think this is due to them being dry and as you have said that flute has been unused and in the sun for a long time.
Might just need CPR~breath life back into it.

Hope you'll post when you get it resolved.
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