Music Instruments Parts

[Enthalpy]

Hello fellow bassoon players! (Plural just in case)

Shoulder straps or harnesses carry bassoons at the boot, or the joints might separate. This is much below the centre of gravity. An extendable part can fasten the strap higher on German bassoons, French ones typically lack it. Also, the holding point is always between both bores, supposedly because wood is thicker there, but when playing the tenor joint is almost above the bass joint, so the bassoonist must roll the instrument manually.

Here's my makeshift solution to carry comfortably a bassoon, in this case a French system. It's comfortable and can inspire a durable elegant design.

The strap still pulls at the boot so the joints won't separate. But it (or some textile prolongation) makes a detour at a part attached to the tenor joint permanently. The strap pulls nearer to the centre of gravity, and more at right side. With proper adjustment, the left hand must pull a bit but no roll effort is needed, very nice.

My part is a ring that surrounds the tenor joint. Then it must be thin: it's few turns of adhesive tape in my embodiment. More adhesive tape holds the ring up and right in adjusted position. It takes several plies or a thicker tape; ruptures made no damage. My textile prolongation is a brand new shoe string.

No, it's not Mali here, but a marketable version should improve few details. The tenor joint has thick wood where the long side holes converge to the hand, at a place that can hold the part. Maybe the part must be open or openable to introduce the strap easily.

Marc Schaefer, aka Enthalpy

Edited January 17, 2020 by Enthalpy

[Enthalpy]

Upon suggestion by Jean-Paul Bosselut, BB. Ninob researched membrane reeds and instruments and published there
la.trompette.free.fr (in French)

Instead of cane, a membrane vibrates on a resonator. It lets air flow in when the pressure in the resonator is high to provide net alternating power from the steady feed. Adapted from the document:

The membrane reed makes very strong sound of poor musical quality. Maybe the aperture was bigger than what fits the resonator: on a clarinet it's less than 1mm high when played, times 10mm width. A tube exceeds easily this perimeter.

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I also have a strong intuition that the membrane shuts brutally and completely the aperture for a portion of the period. This creates unpleasant high harmonics, just like a saturating amplifier does.

To make a pleasant sound, mouthpieces for single reeds have a carefully optimized curved slope to face the reed, which then closes the aperture smoothly.

By similarity, I propose to shape the aperture so the membrane reed closes it smoothly.

Just tilting the aperture versus the membrane would already do it. With luck and an aperture matching the resonator losses, the membrane reed might then also play piano like a clarinet does, and keep a decent sound at moderate strength. If the membrane support is tilted by as much and the support can rotate versus the aperture, this adjusts the inclination.

The aperture's shape can be more elaborate. It can be curved and have several peaks and valleys.

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Maybe the blowing pressure pushing also on the membrane's outer face would let the reed work over a wider pressure range. Or not.

Marc Schaefer, aka Enthalpy

[Enthalpy]

French horn players blow the wagnertuben in symphonic orchestras and often complaint about intonation. The flare isn't supposedly to blame, or it can improve, since narrower French horns and wider tubas are built with excellent intonation.

The lack of compensation must contribute much. Valves add a portion of tube length when desired, and these extra lengths cumulate, while intonation would require to multiply the tube length. If 1, 2 and 3 semitone lengths were tuned for themselves, 1+2+3 semitones would be a semitone short. Widening the 1, 2 and 3 semitones makes a bad compromise.

Solutions are known. Trumpet players move an extra slide to compensate manually the piston combinations. Saxhorns have often a fourth valve or more to replace the 2+3 semitones combination. More complicated valves and tubing can make a compensating system. And at French horns, the musician moves the right hand in the bell to change the height.

All this is difficult at Wagnertuben. Even if made accessible, the bell must be too wide for a hand. Horn players don't use the other systems normally, which cost money and take time to train, possibly too much to serve every second year.

Pictures of Wagnertuben, with a fourth valve:
gebr-alexander.de

I propose to add to wagnertuben a compensation slide moved by the full right hand, not by a finger of the (here left) valve hand. By the palm, or by four fingers, or both, in a movement that imitates the hand action in the bell of a French horn. Some transmission shall also imitate the pitch sensitivity of the French horn. This is cheap, and hopefully, horn players can use it immediately.

I've seen musicians put their right hand at the lead pipe, possibly to apply the mouthpiece on the lips. The wide trigger could then sit there.

The pictured wagnertuben have just after the valves a slide that may serve as a compensator. Or add one at the lead pipe or elsewhere. It needs about a semitone lengthening.

Marc Schaefer, aka Enthalpy

[Enthalpy]

It would be fantastic to retrofit existing Wagnertubas with such compensators.

Marc Schaefer, aka Enthalpy

[Enthalpy]

If a wagnertuba receives a compensator retrofit, a Bowden cable is seducing
wikipedia
it adapts to varied sizes and approximate positioning, for instance if the new parts are clamped on existing tubes.

The same retrofit kit might equip the tenor and bass wagnertuben, with varied displacement ratios, and even be installed by the musician.

A Bowden cable can also be (un-) fitted quickly on the instrument, as the Contraforte's register keys by Wolf and Eppelsheim demonstrate
guntramwolf.de (picture)
that would be snappy enough to evacuate water by the slide.

Amplifying the displacement would be easier before the cable if possible.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Where woodwind joints fit in an other, cork makes them airtight usually, or formerly a wound and impregnated thread. I try heatshrink sleeve at my bassoon's bocal presently.

At least, it needs no skills. The result is stiff and can minimize the dead volume, which should ease the altissimo.

Details should come. Trials not today, it's too late.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Maybe drawbacks like creep will appear over time, but after one daily training, the heatshrink sleeve works.

I noticed no playing difference with cork, but couldn't compare both on real time neither. The tighter fitting immobilizes the bocal as I wanted, but tighter cork would do it too. Up to C# (just below the Sacre) where the comfort zone of the musician and the reed end presently, I noticed no difference; maybe things change at higher notes.

These are the bassoon bocal without its cork, pieces of heatshrink sleeve, the bocal with the sleeves, and a zoom.

The Chinese made the material affordable. It comes in many diameters and colours, length is commonly up to 1m. The diameter shrinks strongly and irreversibly at heat, from a hairdryer, a soldering iron, or with care from a lighter.

Two plies happened to fit at my bocal, first with grease, later without. At first try, the shrunk sleeve moved around the bocal, so I held it with instant glue, which could be applied because the bocal is conical.

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What can improve?

Each ply is too thick and stiff for an adjustment, I had luck. Also, the conical bocal holds in an inverted cone at the bassoon. Maybe double-sided adhesive tape below the sleeve can adjust the diameter and slope if it resists the heat. Or a thread wound below the sleeve, which would give some elasticity.

Heatshrink tape exists too, which enables big diameters, but I expect leaks where the tape ends. Below a sleeve maybe. Would it be thinner?

Marc Schaefer, aka Enthalpy

[Enthalpy]

Second version of my bassoon balancer of January 17, 2020.

The excellentissima idea is kept: hold at the boot, pass through a ring added at the tenor branch.

The ring is added higher on the tenor branch and this relieves the left arm. It has two turns of adhesive tape around the branch plus the length for a gamma eye. It crosses the concave part of the tenor branch, where it separated over time, which doesn't hurt. A professional embodiment must improve that too.

The ring passing between fingers 2L and 3L was only a tiny bit too high, so a longer gamma may enable it.

Sewing thread tightens the gamma. This stabilizes the side position of the gamma to achieve perfect roll equilibrium. Also, the ring doesn't pull any more sidewise nor away the adhesive tapes at the pictures' left that hold it upwards.

Marc Schaefer, aka Enthalpy

[Enthalpy]

I've put heatshrink sleeve on a second bassoon bocal, similarly to Jul 18, 2020 08:13 PM here. 3 thinner plies instead of 2, and this time I needed sandpaper.

240 grit gives a reasonable pace at start. I didn't dare the vice, but sanding in the axial direction and the bocal on a table sufficed. The inner sleeve layer is shortest and the outer longest, so the ends show smooth transitions, better to sand and to introduce in the bassoon body.

I had to glue the inner layer on the bocal with cyanoacrylate, otherwise the sleeves rotate around the bocal. I did it after shrinking partially the first sleeve. This doesn't work every time.

I still ignore if the very stiff sleeves act differently from cork. But I enjoy the strong friction in the bassoon's metal fitting: the bocal doesn't turn any more, one plague less for bassoonists. I wouldn't dare that narrow fit in a wooden body end.

Marc Schaefer, aka Enthalpy

[Enthalpy]

During interventions on a wind instrument, screwdrivers may slip away from the screw and scratch the instrument. Normally it doesn't happen to trained specialists, but operations are slower.

The usual answer, for instance at computers, are cruciform screw drives
wikipedia
and many more, like the inner Torx.

Maybe instruments could adopt such screw drives to gain some safety and time? I understand many screws are taylor-made, and the slot head is then easiest, but just a cross head isn't so difficult. Or could the screws be processed from industrial ones? Keep the head and adjust the length and optionally the pointy end.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Long keys can get play on woodwinds. On a bassoon, a bass clarinet, on contrabasses... they can exceed 1/3m or 1/2m, but 0.2mm play, perhaps 0.1mm, hamper the operation of the pads at the covers. Compressed shafts don't work properly neither. Both do happen when a wooden body gets less or more damp, perhaps warm too.

One good solution splits the function in several assemblies, where the shaft that carries the cover is short. But this isn't always possible or desired.

At least one patent integrates some spring that pushes the shaft at the end opposite to the cover. The musician may push the shaft to the sides too, rather strongly if gliding from a lever to an other, so the spring must be strong. This creates strong stress where the posts hold in the wood, not desired over 1/2 or 1 century. And in the patent's drawings, little room is available for the spring.

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I propose instead to pull the shaft at the end near the cover. This creates no stress in the wood. The spring can reside outside the shaft to have room. I could be the same spring the brings the key to its rest position, especially if this avoids friction or noise.

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Alternately, the shaft could get stops in both directions at the end near the cover, and the opposite end move freely in the axial direction. In mechanical engineering, this is standard design with bearings. In the sketched design example, the screw in black holds in the shaft and presses against its end while the boule's length is adjusted to let the smooth part of the screw and the shaft glide with minimum play.

Usually, the boule is screwed in the body and later planed, bored, threaded. The orientation may then lack accuracy for my second proposal. But other boules exist, in two parts or more, that are already machined and get assembled with the proper orientation after a part is screwed in the body. This would let mass-production machines define the length of the boule and the screw.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Found with gratitude a glossary
shwoodwind.co.uk
so in my previous posts:
Shaft -> Barrel
Cover -> sometimes Cup
Lever -> sometimes Touchpiece
Post   -> Pillar
Boule -> Pillar's ball, sometimes Pillar

[Enthalpy]

The pillars are screwed in a hole in the wooden body presently, so their orientation is unpredictable. The balls are then bored in the good direction, with manual skill as usual, and can get flat faces, a thread, a recess. If present, the conical screw tip accepts some misalignment.

Some designs let align the pillar after it's screwed in the body, at least in patents. My proposal instead:

Without a conical screw tip, the ball could belong to a subpart distinct from the pole and be assembled with proper orientation by brazing. An auxiliary metal sheet can protect the wood from the flame. Maybe auxiliary metal like massive pliers, or water in a sponge, can absorb the heat conducted by the pole. Quenching after brazing helps, faster heating means too if available at workshops.

15µm diameter play on 3mm length leave +-1.5mm tolerance at the opposite end of a 300mm shaft. The luthier could wobble that end by +-1.5mm around the other ball in both directions while the brazing filler solidifies, so the play is symmetrical.

At and near the ball displayed left, only chip machining defines the play. The materials should resist wear and survive brazing temperature. The screws could be commercial parts, possibly modified, maybe with a Torx, hex socket or cruciform screw drive.

The barrel end parts could be brazed, but since the nearby cups and touchpieces are brazed too, welding seems better. Friction welding is seducing, where the parts are pushed and rotated against an other. Maybe a boring machine achieves the speed for the small diameters.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Here the pillar comprises a threaded post, of axial symmetry hence indifferent orientation, and a cap oriented when assembling so its opening accommodates the barrel's head. A ball at the barrel's head accepts misalignments.

The post and the cap press directly against an other, leaving the barrel's head a well controlled play. If a drill bit with spherical tip, or any tool that makes the hollow for the barrel's head ball, also makes the surfaces of the post and the cap that press against an other, the play is more accurate.

A sheet spring could press the cap on the post, provided it's difficult to remove. At the sheet springs I saw, all bends and folds are parallel to an other, hence the bump in the cap to hold the holed spring. If a spring can have 3 or 4 legs instead of 2, the bump and the hole are superfluous.

The head could be welded at the barrel, possibly by friction as already suggested.

These parts can be mass-produced by automatic machines, possibly at a subcontractor, and their assembly saves most manual labour.

The ball of the barrel's head can be of steel of ceramic for accurate shape and to resist wear. A screw through a hole can then hold it at the barrel's head, maybe at the barrel directly. If the post and the cap wear out, they are just replaced.

Marc Schaefer, aka Enthalpy

[Enthalpy]

A similar construction can save most assembling labour at the opposite end too.

That barrel's end slides in its bored ball. This ball doesn't need to rotate and can be slightly larger so the post and the cap press it, or better, the post and cap have a slightly smaller hollow and distinct shapes. Or could the ball be part of the cap? Provided that the spring doesn't twist the barrel's end.

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Some coatings resist wear and brazing heat. Nickel doesn't gall but its unlubricated friction is strong. Chromium glides easily, but few alloys don't gall against it: bronze, aluminium bronze - no information about nickel silver. Nickel and chromium can be ground. Countless coatings exist. Nickel doesn't gall against itself because pairing is irrelevant.

Marc Schaefer, aka Enthalpy

[Enthalpy]

Instruments with sideholes could have inserts there. Or is it already done?

• Smoothening the hole's inner end, where it meets the air column, is easy at an insert before it is mounted but difficult at the wall alone.
  scienceforums
• The hole dimensions adjust the intonation at least at oboes. Replacing the insert chosen in a set is reversible.
• Some oboes have chambers, I claim their resonances make a mellower sound
  scienceforums
  A set of inserts lets adjust the intonation and can keep the resonance unchanged.
• A protruding ring makes the airtight contact with pads. It wastes scarce wood, needs difficult machining, and wood can split there or lose its flatness. An insert is easier and can use durable polymer (Vectra...) or metal.

The inserts are cheaply turned to complex shape.

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Looks feasible with or without inserts: smoothening the hole's outer end, where it meets the pad, could improve an instrument further, like undercutting does at a clarinet.
scienceforums
Flutes do it. Pads covered with gut or fish skin and adjusted with paper may help.

Marc Schaefer, aka Enthalpy

Edited August 29, 2021 by Enthalpy