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Johann

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    138
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About Johann

  • Rank
    Chatty concertinist
  • Birthday 04/20/1951

Contact Methods

  • Website URL
    http://elektor.htl-leonding.ac.at/~jp/
  • Yahoo
    J_pascher

Profile Information

  • Interests
    All about building reed instruments
  • Location
    Upper Austria

Recent Profile Visitors

235 profile views
  1. Johann

    FREE REED PHYSICS - 3

    Hi Tom, i have red some of P. Cottigham's publications now. especially "Analysis of free reed attack transients " Since it is quite a long time as i was talking about additional modes in reed motions in some forums. I am surprised that this letter now more or less confirms my hypotheses i made years ago. Then i was criticized about my theses. Over time i even was not sure anymore, since i could not find a real prove expect that i could hear some of this mode related pitches. I have found some way to control low reeds, without special tool only by hearing and changing the profile, but not as good as i would like to be in control off this. I will read more of P. Cottigham's Publications. Takes time. I am quite happy that there is some research done on the subject. As far as i can see his research are made under comparable conditions as mine. He also uses Matlab and similar equipment. I did not have high speed camera i used strobe light and sycron photography about 20 Years ago. As i told you i am now more in the practical phase of work. Best regards Johann
  2. Johann

    FREE REED PHYSICS - 3

    Hi Tom, yes Tom exactly, still if we look deeper into the subject it may be important to remember that the western reed still behaves comparable, even we can get away with a much simplified model. Sure there are differences in the reed and in the cavity and where the reed is mounted. The circumstances remain the same, we still have a cavity and a reed and a mounting point of the reed all differs dramatically but the reed needs the air to sound. With the western reed, the reed is the dominant part and the cavity, it is nearly neglectable. I also like to point out again on very low reeds it is even more important how this cavity is formed and how big the cavity is. On the very high pitched reeds we all know that we have to take measures to improve the speaking of the reed. All my thinking is influenced by building helicon boxes now for about 20 Years and optimising the sound. My theoretical influence is strongly influenced from may former profession working and teaching in the field telecommunication. I never would say i can't be wrong if someone comes up with other explanations that fit better. The usual models and explanations are for me always a bit to much simplified. Best regards Johann
  3. Johann

    FREE REED PHYSICS - 3

    High Wolf, it is really difficult how we charge sound and timbre. The main key is for me the human vocal tract how we form speech. The frequencies that count to distinguish vocals. So the answer for me, as with most things is somewhere in the middle. Read about https://en.wikipedia.org/wiki/Speech_recognition. This is a part from the german wiki can't find the same in the engisch: "Auf akustischer Ebene spielt insbesondere die Lage der Formanten eine Rolle: Die Frequenzanteile gesprochener Vokale konzentrieren sich typischerweise auf bestimmte unterschiedliche Frequenzen, die Formanten genannt werden. Für die Unterscheidung der Vokale sind insbesondere die zwei tiefsten Formanten von Bedeutung: Die tiefere Frequenz liegt im Bereich von 200 bis 800 Hertz, die höhere im Bereich von 800 bis 2400 Hertz. Über die Lage dieser Frequenzen lassen sich die einzelnen Vokale unterscheiden." Here is the link to the topic in englisch: https://en.wikipedia.org/wiki/Formant To get on we would should think about this. Best regards Johann
  4. Johann

    FREE REED PHYSICS - 3

    Hi tom, we keep on thinking and doing our best, but in the end we never know how others hear the same sound. For me spectrum carts are not as informative as the actual sound i hear. I wish we would have better tools to visualise sound and timbre. But in the end well trained ear is more precise. That's what i realised. I also would like to to some dow back on my opinion about additional mode frequencies, and how much the cont in the resulting sound. I still think such frequencies are more or less present especially under transient conditions, but when a reed is sounded constantly i can't say that i hear or cn measure this additional mode frequencies. Don't trust this single test that all would need much more intense investigation. Especially on very low pitched reeds i have the impression the are noticeable but i don't have a practical way to influence the sound by profiling the reed. My be i am completely wrong with my hypotheses in this respect. As with all as time goes by the opinion on subjects may change especially if no one could come up with a prove. Still i hope younger people will put time in this subject. Unfortunately it is not of major interest to scientists. Still it is good to talk about it so it may be some one will get on it as well. Best regards, Johann
  5. Johann

    FREE REED PHYSICS - 3

    Tom i have the real sound not only the recording, and i think it depends strongly on the individium how we charge the sound. I had my hearing cuve checked some Years ago and then the test showed that i don't have any dropouts and i here quote high tone very well. Other my manly hear the lower components of the sound. So it may be well so that for you the titanium sounds brighter and for me it is the steel. Quite explanable with this 5th harmonic. 5th harmonic is 5:4 major 3rd (c to e1). If the 5th gets dominant it is more like a 3rd mayor is present. You may experiment with the sound by using equalizers try to inforce just the 5th or on the other hand enforce a wider range on the high end. I is common practice to brighten a sound by enforcing Frequencies above 1 khz. Best regards, Johann
  6. Johann

    FREE REED PHYSICS - 3

    No Tom see the index on the right. I did not change anything just the lins are now drown ble on top of orange.
  7. Johann

    FREE REED PHYSICS - 3

    Tom the tongue thickness is not constant it has the usual profile and the tongue bends in a smooth curve similar to the steel profile. But the titanium alloy reed is approximately 1/3 less stiff to get to the same pitch. So your theoretical model uses different parameter, with the same stiffness but different length. To get to the same pitch with nearly equal reed dimensions stiffness mast the different what results in less strong higher harmonics. That is for me a known circonstance if i make reedsets with different stiffness. Johann
  8. Johann

    FREE REED PHYSICS - 3

    Hi tom, the are not equal. I have attached the same chart but this time with blue line on top.
  9. Johann

    FREE REED PHYSICS - 3

    Please look at the attached pictures i also mentioned that test condition is totally equal and air pressure was 500 PaN/m2. Reeds were mounted equally on the same tunningtabel on exactly the same place. Nothing special about the microphone is an electrede micro. I don't say this are ideal test condition but enough to see differences in the chart. It my be you war mistaken steel has much more higher harmonics look at the chart and listen again. Don't take the blips to seriesly the my be caused by the wind machine i would need to repeat the test again with different pressures so i could tell for sure if the are from the windsource or not. The test condition should be carried out in a special noce damped room as well, i could do this in the sound laboratory at my former workplace. But this test was made on may workplace. All together would be a fillings subject for a dissertation. For now i don't have more. Best regards Johann
  10. Johann

    FREE REED PHYSICS - 3

    I may be well wong on how the final instrument with titanium alloy reeds sound, i only know small accordions with brass or bronze reeds. All would need intense verifying and making complete sets with titanium alloys. Also keep in mind we only talk about reed sets my experience is that the instrument itself has also influence on the resulting sound and with "typical formant range" in the spectrum. We have et list some different filtering depending on the instrument. Comparing ist therefore alway not so easy. Best regards Johann
  11. Johann

    FREE REED PHYSICS - 3

    " Listening to Johan’s sound files of a steel reed vs a titanium one, I really couldn’t tell the difference. The chart does show the different strengths of the harmonics, but our ears probably aren’t designed to distinguish between sounds that are proportionally so similar, especially since both seem to have strong odd harmonics as the defining feature of the tone. [...] Tom doesn’t’ agree with Benade’s explanation and convinced me it may not be correct, but that is as far as I got. Dana" Hi Dena use headphones and you should hear the difference. Is not as much as one would expect and under real conditions it may be even less. Still i expect a more mellow sound as brass. This are all hypothesis that need to be proven in real Instruments. Also it is not so important for people who build instruments to understand way the different sound are produced. Important is that we know we can influence the sound by changing Profile and reed length. We just have to accept that reed produce beside the "normal" harmonics, that are more or less in a known relationship to each other, also harmonic frequencies that are in amplitude much less but don't fit into this scale. Changing profile will result in varying this frequencies and amplitudes of this so called inharmonic frequencies (additional mode frequencies). Relay on your ear by making reeds there is no real practical mathematical background that would really help in making reeds sounding more pleasant to our ears. Please point me to the differences of Bernard's explanation. Best regards Johann
  12. Johann

    FREE REED PHYSICS - 1

    Ok Tom i think it is mostly because it is very difficult for me to explain it not in my native language. This is why i would prefer that you ask question. You are on a very good way but things are often simplified to much. I know we have to do so to get on. But to understand all a bit better we have to proceed and think about it in a more complex scenario. For the simplified approach you are right, but once you have the simplified modul right you have to take more in account. Best regards, Johann
  13. Johann

    FREE REED PHYSICS - 1

    Hi Tom, i am well aware of this as well, also keep in mind that not only with increase of volume the amount the pitch trops with increase of volume depends strongly on the spring stiffness off the reed. Also think in witch way dissipation comes noticeable what is causing the damping? Inertia material dissipation of the reed? No it is the air surrounding of the reed within a cavity that is more or less resistant compatible with bass sound boxes. But this is also in relation with resonance and coppeling. Don't see this as a completely different subject. I am electronic telecommunication engineer as well and i know how things are working and i know very well how LC or RC circuits or series of circuits behave and can be calculated and acoustic circuits don't behave completely different. For me it is not a matter that i have to prove it. It is or more less well known design knowledge. My be i can't explain it quit well enough because my english is not as good as it should be. Don't put it away think about it. If you have questions i will tray to explain. But i am not prepared to present more explanation without detailed further questions. Also is not for me to get a more intense understanding of this circumstances. At this time in my live (i am 68 Years old now) i am more in building of accordions especially the last teen years. I am retired from my professional work as telecommunication engineer and academy teacher in this field. Johann
  14. Johann

    FREE REED PHYSICS - 1

    Tom i still don't know what your theoretical model includes, only the the reed as vibrating single side mounted beam? Or also the cutting of the air beam through the slot? The western reed is an impulse generator more like sirens not so much like a tuning falk. Johann
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