Enthalpy

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  1. Enthalpy

    String Instruments

    Steel strings rust, slowly at a piano, faster at mallet instruments that play sometimes outside and are closer to the musician's hands, and more so at plucked instruments. While six strings are easily replaced, zithers and dulcimers can have 30 strands of 3 strings. But how stable can stainless strings be? Experiments shall decide. Stainless steel is abandoned at the piano; I suppose only austenitic steel was tried. Creep and losses may be worse than with carbon steel. All must be hardened by deep cold-work, but I don't have good data for this condition, so the following is unreliable. Martensitic stainless behaves much like carbon steel. Tempered below 300°C, the X20Cr13 stays tough and offers YTS>=1400MPa before cold-work improves it, as is expected but not documented. More alloying elements and less C, like Cr17Ni2Mo, resist corrosion better but offer less hardness and toughness. Variants of X20Cr13 with more carbon exist in some countries, others contain V and similar to form hardening carbides. Among them, X11CrNiMo12 (Böhler T552 and elsewhere) is a turbine alloy with known behaviour at 500-600°C, including creep. Cold-work and under-tempering aren't documented, logically. Tempered at 570°C and without cold work, it offers YTS>900MPa. Expansion 10.3ppm/K and E-modulus drift -174ppm/K (acting -87ppm/K on the frequency) suit a cast iron frame better than high-carbon steel does. Precipitation-hardening martensitic steels harden by ageing after easier cold-working and they resist corrosion far better than high carbon steel does. I have no modulus drift data about the Maraging Ni18Co12Mo5Ti (tough YTS~2360MPa without cold work) but expansion like 9.9ppm/K could fit cast iron. The stainless X3Cr13Ni8Mo2Al aka PH13-8 (Böhler N709 and elsewhere) offers tough YTS~1400MPa which cold work supposedly improves, expansion is 10.3ppm/K like carbon steel. The stainless PH15-7Mo becomes martensite by cold-work prior to ageing (YTS~1800MPa, can improve?), it expands by <9ppm/K to suit a cast iron frame better. Ledeburitic stainless resembles high-carbon steel. Hrc=57 to 60 as tempered nearly suffices, but can it be drawn, can wires be bent? Expansion 10.1ppm/K and E-modulus drift -174ppm/K for X90CrMoV18 suit a cast iron frame better than high-carbon steel does. Austenitic stainless harden by cold work and stay tougher than carbon steel. X12Cr17Ni7 achieves quickly 2000MPa and more, X2Cr17Ni12Mo2 needs deeper area reduction but resists finger corrosion better. Undrawn 15.6ppm/K would fit a frame of austenitic stainless steel or copper alloy. Precipitation-hardening austenitic steels expand even more: 16.2ppm/K for X5Ni26Cr15Ti, whose response to cold drawing isn't documented. Duplex stainless strings would excel against corrosion. YTS and toughness respond to cold reduction similarly to X12Cr17Ni7. 12.5ppm/K for X2CrNiMoN22-5-3 suggests a frame of duplex or austenitic stainless steel. CoCr20Ni16Mo7 resists corrosion better than all steels. It's known to exceed 2050MPa by cold-work plus ageing. 12.3ppm/K would match a duplex or austenitic frame. Nickel alloys for turbines are optimized against creep and known to harden by deformation. Expansion of 12.3ppm/K and E drift of -313ppm/K would let the alloy 718 fit an austenitic frame. Marc Schaefer, aka Enthalpy
  2. Enthalpy

    String Instruments

    What lets the tuning of a metal string drift? Humidity has no expected quick effect on steel. Creep acts very slowly at a piano, where margin below the proof strength might matter, knots quality too. Cold-drawn high-carbon steel expands by 10.4ppm/K. This compares with the string's stretch: 1111MPa/210GPa = 0.53% for 1.1*C. The sqrt drifts the frequency by -980ppm/K. Young's modulus drops by 300ppm/K or less: 210GPa to 205GPa from +20°C to +100°C, accelerates above. At constant length, the sqrt drifts the frequency by -150ppm/K. The change of the string's speaking length, for instance 12ppm/K, is negligible. The frame's expansion and deformation matters much. Stretching the string by 0.74% for 1.3*C reduces to -704ppm/K the thermal expansion effect. But if a string used at 0.8*C isn't overspun, the thermal expansion effect climbs to -1860ppm/K. The relative importance of Young's modulus drift goes the opposite way. Strings of cold-drawn titanium alloy, if practical, would expand less: 9.3ppm/K for Ti-Al6V4 vs 0.57% stretch at 1.1*C, while Young's modulus drops by 450ppm/K. Cold-drawn austenitic stainless steel seems to reduce its Young's modulus as quickly as carbon steel, but the X2CrNiMo17-12-2 expands by 16.2ppm/K (at least when annealed!) and the PH 15-7 Mo by 9ppm/K in condition RH950. Prior to cold-working, duplex X2CrNiMoN22-5-3 reduces its Young's modulus as quickly, but expands by 12.5ppm/K. Gut, polyamide and fluorocarbon polymers behave differently. ========== A perfect steel or cast iron frame expands by 10.4ppm/K too, leaving -150ppm/K due to the drift of Young's modulus. So if you tune at +20°C a cimbalom with hypothetic perfect steel frame and play it outdoors at +10°C, it goes sharp by 0.15%. Inaudible to most people, more so if all strings drift equally. In contrast, a wooden frame does drift, over temperature with some woods, and by humidity always. If the temperature changes by 2K in your room or concert hall, the piano with iron frame drifts by 0.03%, inaudible. ========== The strings' tension deforms the frame, whose Young's modulus drops with temperature too. So should its metal expand faster as a compensation? I don't believe so. The frame must deform far less than the strings to make the tunings independent. Also, the frame's deformation varies among the strings, so thermal expansion couldn't compensate it everywhere. Better a stiff frame whose expansion compensates only the strings. The frame is naturally bulkier than the strings anyway, and it must vibrate less, but its shape too must be stiff. ========== The frame can compensate the strings' Young's modulus drift too. At cold-drawn high-carbon steel stretched for 1.1*C, it acts as 0.15* the thermal expansion, so 12.0ppm/K at the frame would let play from 0°C to +40°C without the 0.3% frequency drift. For instance the stainless duplex X2CrNiMoN22-5-3 offers 12.5ppm/K, is strong and has nice fabrication capabilities. The martensitic X20Cr13 would be less perfect with 10.2ppm/K and the usual austenitic alloys less good with 15.8ppm/K. Aluminium expands more: AA2014 22.7ppm/K, AA5083 23.8ppm/K. 10K variation would detune steel strings by bad 1.1% and 2K by not good 0.2%. For Ti-Al6V4 strings too (harder alloys exist), a frame expansion of 11.9ppm/K would be good. That is, titanium strings could coexist with steel ones, overspun or not. Marc Schaefer, aka Enthalpy
  3. Enthalpy

    Quick Electric Machines

    More and more aeroplanes go electric, as the Beeb reports from Le Bourget bbc.com some claiming far better performance from battery-powered craft than my estimates here despite their wing isn't as wide. Hydrogen is missing in the report. Because of that, "electric" aeroplanes are said not to fly far, but the limit results from batteries. Hydrogen tanks and fuel cells give aeroplanes much more range than kerosene does.
  4. Enthalpy

    String Instruments

    Catalytic nickel protects against corrosion and is excellent against galling. I used some, with embedded Ptfe particles, at about 600MPa pressure and nearly no speed, against a martensitic stainless steel that galls horribly. The friction was tiny and very smooth without the stick-slip felt with zinc or phosphate layers against tempered steel. Embedded particles of MoS2 or graphite may be good too. Easy and smooth gliding would improve the bridges and saddles under the strings of some instruments. The piano uses steel nails to deflect the strings at the bridge. Wood receives already a gliding surface, the nails not, despite the force is bigger on them. Catalytic nickel with Ptfe should stabilize the tuning earlier. Some pianos have agraffes on the bridge instead. Same advantage. At least the cimbalum bends the strings over a metal rod at the many bridges. Easier gliding would equalize the tension among the sections between the bridges to improve the intonation. Especially important as the cimbalum has several strings per note. Many instruments have metal saddles or pins near the ends: harp, piano, cimbalom... where the deflection can be big. Better gliding would stabilize the tuning here too, just like violinists put graphite on the wood there. Tuning pegs would better rub smoothly too. They exist of hard wood or metal presently. At the violin, stick-slip of ebony pegs in the maple pegbox is a pain. But to replace ebony, nickel should rub strongly (no Ptfe), be black (graphite glides too easily), leave the fingers clean (embedded Ptfe doesn't). My gut feeling is that a hard polymer like LCP, possibly with a filler, has better chances than a metal. The piano, harp, cimbalom and others have metal tuning pins. Catalytic nickel protects against corrosion, rubs strongly without galling, and hopefully moves smoothly. Steinway pianos have already nickel-plated steel there. At string hooks, especially where piano strings make a U-turn without a knot, the strong friction of nickel might help tuning. Marc Schaefer, aka Enthalpy
  5. Enthalpy

    String Instruments

    Here I propose a simpler notes chart for the cimbalom. The bass strands keep the usual positions up to B=234Hz, the rest differs: Semitones progress smoothly but for three jumps. At the jumps, the sections overlap by three semitones, similarly to trill keys at woodwinds. The sections have a constant interval. At the violin it helps. I imagine this chart makes the cimbalum easier to learn and play, but again I don't play it. Example of a usual (but incomplete) chart: beyondkarpaty.mutiny.net Hammered dulcimers would resemble more, but the intervals and bass strings differ. A pair of straight dampers can reach C=1051Hz while most Schunda-like models stop three semitones earlier. They are far from the struck positions. Schunda had achieved a nearly rectangular instrument shape at the cost of complicated notes chart and very inconsistent string sound speed even among consecutive notes. In my chart, the trapezoidal shape keeps the string sound speed between 1.10*C and 1.16*C at the treble and medium, varying very smoothly even at the section jumps, and decreasing gently to 0.54*C at the bass. Other string lengths would adjust these example figures, say between 1.20* and 1.27*. All bridges and saddles are straight on the drawing, but curves as at the piano could further equalize the string sound speed or limit the instrument's width. The outer bridges leave 10% non-speaking length in the corresponding strings, less than at a piano, but this can increase if accepting a slower propagation, at all these notes or only the lowest ones. Schunda's design has 39 strands, my chart has 43 with fewer spun strings. I suppose three strings per strand suffice. Marc Schaefer, aka Enthalpy
  6. Enthalpy

    String Instruments

    And oops. All pictures show one hook and one knot per string. Bad reason.
  7. Enthalpy

    String Instruments

    Here's a sketch of a big cimbalum that widens enough at the near strings to keep a good tension in the medium register, as suggested here yesterday. Its slope resembles much a small cimbalom. I fully ignore whether a wider instrument is difficult to play. If it helps to play near the centerline, the strings' tilt can be kept using taller bridges. For nicer and more uniform timbre, sound is here consistently 1.22* to 1.35* as fast in the medium strings as in the air. It remains faster than in air in half of the bass strings, whose plain steel saves money, then decreases in the spun strings to 0.58* at the lowest note. I'd keep the mass of the strings, that is, thinner if longer. Less stress is also welcome at the bigger frame. I've kept the distance from the bass bridges to the outer rails. Bringing less stiffness, strings passing the bridges straight might let shorten this distance. It is very short at a piano. Thanks to its metal frame, the piano also extends its soundboard very far under the agraffes and tuning pegs: to be copied if possible. Marc Schaefer, aka Enthalpy
  8. Enthalpy

    String Instruments

    Here are some thoughts about the cimbalom. en.wiki - fr.wiki - cimbalombohak.sk - cimbalom.hu Big warning: I don't play the cimbalom nor any related instrument, so much here is probably b**ocks. If at the end one detail or an other makes sense, fine. Many instruments are called cimbalom, the name varies also much, and other instruments can be very similar. I consider the grand cimbalom, of Hungarian style, developed by Schunda around 1870. ========== If I see properly, the two sets of dampers are pushed down directly by long beams, possibly less stiff than needed. Hoping to make settings easier and more stable, I suggest: Individual movements for the dampers hold at a fixed beam; Individual springs to push each damper against a string course; One common action on each side, moved by the pedal, to pull all dampers from the strings; Optionally, the contact between the action and the dampers can be adjusted individually. The dampers for the central portions of treble strings still need some transmission. I wish the strings would sound for longer with the dampers. Enabling fine adjustments must help. ========== The medium alternates long string courses with others split in two by a bridge (bridges have voids for the uninterrupted strings). Angles by the bridges put courses higher at one end or the other to help the musician hit the desired note. If no bridge shortened these longer courses, an identical ratio between the full length, the longer part and the shorter part would be the golden number, (1+sqrt(5))/2 ~ 1.618. At identical sound speed in the strings, the intervals would be 8 or better 9 semitones (minor or major sixth) between full length, long part and short part, so 2*9 courses would span 27 semitones at uniform sound speed. The bridge loses about 2 semitones. That's still 4 semitones more than presently, with notes arranged more logically and with uniform sound speed. Whether this is advantageous, and enough so to learn a new string chart? ========== Why 4 strings per note? For a strong attack but longer sustain at medium and treble notes, 2 strings offer eigenmodes with no net force on the bridge and soundboard, and 3 strings suppress the roll moments too. 4 bring no further advantage here, and the piano has only 3. String inharmonicity improves with finer strings, and then more strings keep some moving mass. Though, I believe inharmonicity has been hugely overstated; it's not even a drawback with reasonable diameters like here. Maybe 4 strings cost less than 3. They replace a time-consuming knot on the instrument's left by a turn, plus one cheap tuning peg and its hole at the right. Pianos share some wires before and beyond the turn among adjacent notes, but their tension is very nearly the same, as opposed to the cimbalom. I suppose there is some design flexibility here. ========== Existing instruments widen very slowly at the low notes. Did Schunda consider his design already bulky and heavy enough? Consequently, the nearer strings are far too short, see the drawing: the farther medium strings are healthy 1.23*C or even 1.35*C long (as compared to the sound speed in air) but the nearer medium strings drop to 1.03*C or 0.83*C, and the nearer bass strings to meager 0.37*C, usually a receipe for bad sound. Small cimbaloms widen much more strongly at the nearer strings. Would it hamper playing the big instruments? At least, longer near strings would keep a decent sound speed. The farther medium strings could keep their length and the nearer be 1.3* as long. With the present notes chart, the nearer medium strings would be 1.08*C and 1.32*C long, perfect for plain steel strings and for the transition to spun bass strings. If keeping straight bridges, the lowest bass string would be 1.63* longer, or more decent 0.60*C. Drawing later and maybe. The instrument then widens from 1.5m to 2.1m. Many cimbaloms still have a wooden frame. I hope a metal frame would stabilize the tuning and let the instrument weigh less than Schunda's 1870 design, 100kg. Later and maybe. ========== The angles in the strings hamper the movements of the bridges and put also much pressure on the soundboard, which must be sturdy and is even supported by pillars under the bridges. Efficient reasons for the lack of sonority. Zig-zags at the bridge, like at the piano, would solve all. They are not possible at the highest strings. Elsewhere, they need an instrument higher at the sides, which a metal frame should enable. Later and maybe. Marc Schaefer, aka Enthalpy
  9. Enthalpy

    Hear a Luthéal

    From fresh pixel counting on grand pianos pictures, their treble and medium strings propagate the sound 1.2* as fast as air. The factor drops smoothly at the bass, which are spun with copper as soon as the factor is 1. Hungarian style grand cimbaloms have some strings long as 1.2* air half-waves, for few notes even 1.35*, but this drops to 0.83* at some plain steel strings, and to meagre 0.37* at the lowest spun strings. The puzzling arrangement of the strings gives very different string lengths to neighbour notes, jumping from 0.83 to 1.35 and back within semitones. So if the factor 0.83 contributes to the sound of some cimbalom notes, an imitating grand piano could be lowered by 6 semitones from 1.2. Or by 7, a fifth, for easier transposition. The cimbalom has also 3 or 4 strings per note except the lowest ones. At a piano, their tunes must match exactly to sound good. At a cimbalom, which has usually a wooden frame and produces from most strands several notes separated by bridges, the perfect match must be rare and brief. Unmatched tunes in strands may contribute to the cimbalom sound with its typical lisp. The prepared grand piano can imitate this easily. And of course, use special hard hammer heads or mallets. Marc Schaefer, aka Enthalpy
  10. Enthalpy

    Quasi Sine Generator

    Algebraic proof that H5=H7=0 for the waveform with H3=-135dBc, having 35 transitions and T=210, here on June 01, 2019 Waveform ----------------------------------------------------------------------------------------- Dirac sign | - + - + - + - + - + - + - + - + - + Positions | 0 5 6 9 12 14 17 25 27 31 33 36 37 42 43 50 51 52 | -5 -6 -9 -12 -14 -17 -25 -27 -31 -33 -36 -37 -42 -43 -50 -51 -52 ----------------------------------------------------------------------------------------- Harmonic 5 ----------------------------------------------------------------------------------------- Modulo T/5=42 | 0 5 6 9 12 14 17 25 27 31 33 36 37 0 1 8 9 10 | 37 36 33 30 28 25 17 15 11 9 6 5 0 41 34 33 32 ----------------------------------------------------------------------------------------- +21 if -Dirac | 21 5 27 9 33 14 38 25 6 31 12 36 16 0 22 8 30 10 | 37 15 33 9 28 4 17 36 11 30 6 26 0 20 34 12 32 ----------------------------------------------------------------------------------------- Ordered | 0 0 4 5 6 6 8 9 9 10 11 12 12 14 15 16 17 20 | 21 22 25 26 27 28 30 30 31 32 33 33 34 36 36 37 38 ----------------------------------------------------------------------------------------- Cycles | (0 14 28) (6 20 34) (8 22 36) | (0 21) (4 25) (5 26) (6 27) (9 30) | (9 30) (10 31) (11 32) (12 33) (12 33) | (15 36) (16 37) (17 38) ----------------------------------------------------------------------------------------- Harmonic 7 ----------------------------------------------------------------------------------------- Modulo T/7=30 | 0 5 6 9 12 14 17 25 27 1 3 6 7 12 13 20 21 22 | 25 24 21 18 16 13 5 3 29 27 24 23 18 17 10 9 8 ----------------------------------------------------------------------------------------- +15 if -Dirac | 15 5 21 9 27 14 2 25 12 1 18 6 22 12 28 20 6 22 | 25 9 21 3 16 28 5 18 29 12 24 8 18 2 10 24 8 ----------------------------------------------------------------------------------------- Ordered | 1 2 2 3 5 5 6 6 8 8 9 9 10 12 12 12 14 15 | 16 18 18 18 20 21 21 22 22 24 24 25 25 27 28 28 29 ----------------------------------------------------------------------------------------- Cycles | (2 12 22) (2 12 22) (5 15 25) | (8 18 28) (8 18 28) | (1 16) (3 18) (5 20) (6 21) (6 21) | (9 24) (9 24) (10 25) (12 27) (14 29) ----------------------------------------------------------------------------------------- Marc Schaefer, aka Enthalpy
  11. Enthalpy

    Woodwind Materials

    Most woodwind have corks where the joints fit in an other, and corks let woodwind bodies vibrate lengthwise. I take E=G=6MPa and losses=2.2% @1kHz for cork amorimcorkcomposites.com unexpected small losses, but cork does rebound, more so than many elastomers. ========== Let's take a soprano clarinet as an example, with D=14.6mm bore taken as uniform. At the mouthpiece, 1Pa creates 0.17mN axial force. At the fittings, the oscillating air pressure acts on Do~20mm Di=14.6mm to create forces as strong. The bell's flare too experiences axial forces. It the corks are 10mm long and 3mm thick (I have no clarinet at hand), their axial stiffness is 1.3MN/m. This resonates a 20g mouthpiece around 1.2kHz, and together with a 30g barrel at 0.8kHz. The bell resonates somewhat lower, and the driving force can originate elsewhere. If the upper and lower joints weigh 0.15kg each, their fitting resonates them around 0.6kHz. Or rather, these resonances combine. The joints, especially the bell, add their own lengthwise resonances. The frequencies reside at the fundamental's lower clarion to the upper registers, and at the strongest harmonics of the chalumeau register. Bad luck. 1Pa and 0.17mN would move the parts by 0.13nm in quadrature, but Q=45 resonances amplify this to 6nm in-phase. Facings create a lossy pulsation of 10-12m3. Compare with the air column: 1/2* 0.25m D=14.6mm make 21cm3 where 1Pa induce 1.5*10-10m3. A clarinet has Q>100 at these registers, so the lossy pulsation is 1.5*10-12m3. Corks create much losses at a clarinet, according to this model - but experiments decide as usual. It would be worse at an oboe or a bassoon, where the bore is a smaller fraction of the wood section. Q=45 lets affect one note and the neighbour semitones for being so strong. The resonance is too wide to conceal it between two notes, cork is too variable too. Not only is power lost. The blowing resistance is smaller, and the emission of the upper register may become harder. ========== A century ago, woodwinds had impregnated thread coiled on the tenons and bocals. Did it resonate less strongly? I didn't compare when I let install corks at my bassoon, alas. Many elastomers resonate less than cork does. Perfluoroelastomers are an extreme case, they are also hydrophobic and they glide well. Others are easier to glue and cheaper. A limit is that damping materials creep, so the fitting eases over time. ========== Some wooden flutes have silver tenons to connect the joints, for instance Yamaha's YFL-874W and YFL-894W europe.yamaha.com I had suggested that these tenons dampen the flexural resonances, here on Apr 01, 2019 they look also excellent to dampen the lengthwise resonances at the fittings of all wind instruments, since silver absorbs vibrations and is also stiffer than cork: 150MN/m for D=14.6mm e=0.35mm L=10mm. I take a perfectly stiff contact between the metal rings. On metal flutes, the bare accurate adjustment is airtight and slides gently, thanks to thin metal. I suppose that metal tenons in wooden flutes have a location where the diameter doesn't follow the deformations of wood. Maybe ebonite is stable enough that mouthpieces don't need an inner metal lining and the manufacturers don't learn new materials and fabrication methods. But the luthiers and workshops not used to flutes would have to learn adjusting metal rings. Besides (sterling) silver, PCM is a good instrument alloy, and some Ni+Co alloys are known dampers that can be electroformed too: easier for pure oboe or bassoon luthiers. More here on Nov 04, 2018 At a flute B-joint, the fitting is already much shorter than what a clarinet, oboe or bassoon needs. At a conical bore, the fitting must be cylindrical, hence a bit wider that the cone upwards and narrower downwards. Thin metal needs less wood thickness than cork and keeps more sturdy joints. When a clarinettist tunes his instrument down, this creates presently cavities at the air column with deep corrugations. Metal fittings improve this. But the chamber of a saxophone has important functions, so a new design must keep it. Marc Schaefer, aka Enthalpy
  12. Enthalpy

    Quasi Sine Generator

    35 transitions improve further the waveforms with T=210: -135dBc. H1 H3 H5 H7 H9 H11 H13 | T a b c d e f g h i j k l m n o p q ============================================================================================= 0.52 -126 nil nil -11 -6 -8 | 210 2 7 8 10 12 14 15 16 19 27 28 31 33 40 42 50 51 0.47 -135 nil nil -28 -4 -8 | 210 5 6 9 12 14 17 25 27 31 33 36 37 42 43 50 51 52 ============================================================================================= T=140 and 180 with 35 transitions aren't quite as good as T=210. Neither did 15 transitions provide good waveforms with T<=702, T=840 nor T=1050. Marc Schaefer, aka Enthalpy
  13. Enthalpy

    optical computers

    I had suggested an instruction copied from the Vax 11 's Subtract One and Branch, on 26 October 2015 and the 86 family has already one. ========== One computation I have quite often in my programmes is if (|x-ref| < epsilon) The operation on floating numbers is lighter and faster than a multiplication, hence easily done in one cycle. It's often in inner loops of heavy computations. Processors that don't provide this operation should. Depending on hardware timing, the instruction set could provide variants, preferibly the most integrated one: |x-ref| Compare |x-ref| with epsilon Branch if |x-ref| < epsilon Simd processors (Sse, Avx...) could compute on each component and group the comparisons by a logical operation, possibly with a mask, in the same instruction or a following one. Inevitably with Simd, it makes many combinations. ========== An other computation frequent in scientific programmes is if (|x-ref|2 < epsilon) It looks about as heavy as a multiplication-accumulation, but denormalizations take more time. If it fits in a cycle, fine, with the comparison and the branch, better, but it's obviously not worth a slower cycle. Here too, Simd machines could group the comparisons by a logical operation. I feel the square less urgent than the previous absolute value, which can replace it often. Also, a test is often done on the sum of the squared components of the difference instead, and such a sum is also useful alone, without a test nor a branch. Marc Schaefer, aka Enthalpy
  14. Enthalpy

    Saxophone tweaks

    Hello everyone and everybody! I suggest to use the reed and mouthpiece from an alto or bass clarinet on an alto or tenor saxophone with a special bocal. The sound of a woodwind depends strongly on them, here it might resemble a tárogató. The bass clarinet and tenor saxophone can already swap the reed of similar size, but only a clarinet mouthpiece has a facing curve to match the clarinet reed's profile. The designs differ much. Not only is the clarinet facing's curve steeper at the tip, the bore is also much smoother. The bocal fits in the saxophone's mouthpiece but surrounds the clarinet's one, demanding a new bocal design. Proper intonation needs to tweak the evolution of the section at the new bocal and possibly put an insert in the mouthpiece. Corrugations may be necessary at the entrance to soften the sound, as the saxophone has much wider tone holes than a clarinet or a tárogató. I suggested to produce the bocal by metal deposition or graphite composite on Jan 01, 2018 - May 02, 2018 - Dec 04, 2018 Whether a saxophone can play pianissimo then? Marc Schaefer, aka Enthalpy
  15. Enthalpy

    String Instruments

    I suggested to replace spruce or sycamore with yew (Taxus baccata), here on February 10, 2019 12:33 AM, to increase the flexibility of the midrib of traditional harps while keeping the resistance. This applies to much of the harp's soundboard too. Wherever the strings' tension makes the soundboard too stiff, yew will be more flexible and louder. It would apply to any instrument whose strings tension limits the soundboard. How does yew sound in a harp? This must be experimented. Yew was sought after for mandolins, not only for long bows. The definitive way to build loud harps should be my soundboards parallel to the strings, which don't suffer the same limitations hence shouldn't benefit from yew. Marc Schaefer, aka Enthalpy