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ttonon

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Chatty concertinist

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  1. I suggest pure ammonia. It's very effective at dissolving grease and grime. More eco-friendly cleaners are those containing orange oil, like Go Jo and others, but I don't think these are as potent.
  2. Stephen, thanks for the info, but this is really not directly related to free reeds. The chanter of bagpipes in Western Europe are double reeded, and thus resemble oboes and bassoons. I understand that in other countries they are single reeded, like clarinets. But in all cases, they are beating reeds and not free reeds. I'm sure many here know that beating reeds regulate the pressure pulses to a vibrating air column, and the acoustic vibration modes of this air column are what produce the musical tone. That's why the speed of sound is a relevant parameter in the tuning of these instruments. Such is not the case with western free reeds, whose sound source is the vibrating cantilever of the reed tongue, and this vibration doesn't on the vibrations of an air column. With the Asian (symmetric) free reeds, however, there is an acoustic coupling between the reed and an air column, so there, the speed of sound is relevant. The effects of temperature on western (unsymmetric) free reeds, however, is thus an entirely different effect than the effects of temperature on the vibrating air columns of woodwinds and Asian free reed instruments. Best regards, Tom
  3. Hi Wally, in my latter years, I've become more direct and to the point. I wasn't always so, but I find it to be the best overall approach because when I become too concerned with how people choose to react to my writing, I waste a lot of time. I've learned that people who say they are "belittled" by others are most often choosing to feel belittled, and they are motivated for that. Most often it's because they have no factual or rational defense, and so attacking the other person is the only way they can keep asserting their erroneous position. So why do you choose to feel belittled? I had no intention of belittling you. I addressed only what you wrote, not you personally, and even you (now) acknowledge that you made errors in what you wrote. So why condemn me for pointing out your errors, your incompleteness, and the unusual physical theories you put forth, and still do put forth? (By the way, you can't belittle me because I know who I am.) Have you noticed that people who claim to be belittled accuse the other person of behaving in the displeasing way they themselves are behaving? Your comment about me poisoning the group is a good example. It's you who is poisoning the group with your language and with your attack on me. It seems you want this group to be poisoned, because when it is, you believe most everyone will see me as the miscreant. I think you're probably wrong. When people correct me for my erroneous thinking, I usually thank them. You can look through this thread for proof of that. Why do you choose instead to throw a tantrum? Why are you asserting that you cannot make any error regarding the laws of physics, at the same time you're denying any reference to physics? This is childish behavior. I ask you this because I still have hopes you can reconnect with your inner self who happens to be a well-meaning, adult human being. I think you just lost sight of that. Best regards, Tom
  4. Sorry, I hate to drive home the point, but virtually all people who say they are basing their observation on experience provide at least a semblance of a physical theory to support their claim. Wally is one example. He reports his observation that variations of pitch occur with changes in humidity. That's fine, in itself and I have no objections to it. But he goes far beyond that when he asserts his theory that the swelling of the wood because of changes in humidity causes changes in clamping pressure on the reed assembly, and that's what causes changes in tuning. It's comical, like shooting at someone in the dark. He says he doesn't want to get into the science of it all but expects us to accept his scientific theory on why he observes what he does. Wally, let me ask, why don't you just state your observation and leave it to more technically competent posters to devise a physical explanation?
  5. Wally, when you say you will "stay away" from the math, physics, etc., then make a statement about what you think the physical quantity "pressure" has on another physical quantity, "frequency," with a trail of invoking other physical concepts such as "humidity" and "air density," you're contradicting yourself. In your mind you have a physical theory, even if you don't recognize it as a physical theory. Thus, you are not "staying away" at all. In my view, your theory is not only incomplete, but also erroneous. Try making your theory more complete, and I might listen more to you. Best regards, Tom
  6. No, but it's helpful. Your abscissa incorporates the idea that octaves are equal intervals, by perception, and that's correct. The distance between each of the "A's" is the same. I was visualizing the axis with frequency as the variable, which would erroneously stretch out where the "A's" occur, resulting in a straight line. Thanks for the example.
  7. Hi John, I agree with your correction. I'll change my post to read, "... overtones, or partials, often in whole number ratios of a fundamental, in which case they are called harmonics." In Physical Acoustics, these terms have specific meaning. The overtones of a tone generator are generally not harmonics, but with instruments that have sustained tones, such as woodwinds, bowed instruments, and free reeds, we don't hear the full overtones and the upper components of the waveform we do hear, called partials, are harmonic. They must be harmonic because the forcing function of these instruments is periodic, which requires that the musical tone and all its partials be exactly periodic. When these instruments are played, a cooperation among all overtones is achieved, whereby only the value of the overtone at the harmonic frequency is utilized. We don't hear the rest of the overtone. With instruments that produce transient sounds, as with struck or plucked instruments such as pianos, guitars, xylophones, bells, etc., there are no time constraints, and the tone generator is allowed to sound all its overtones, which mostly are not strict harmonics, though they are tuned so that the non-harmonicity doesn't sound more like noise. But even some instruments, such as cymbals and drums, do produce a kind of pleasing noise when used in the right place. The sounds from all these instruments are interesting and pleasing, much because of these nonharmonic features. But it's often quite a chore to tune bells and bars so that their overtones provide a pleasant musical tone when we hear them as upper partials. With strings, there isn't much of an issue with such tuning, and the stretched overtones we hear (because of stiffness) are most appealing and advantageous in providing us with music. But of course, proper string design eliminates too much stiffness, which would lead to such overtone issues. For instance, as you make a string more stiff or thick, it soon becomes a bar.
  8. Hi Dave, you're right. I remember this now but it was so long ago. Pitch is subjective and is a way of ordering tones along a musical scale, not something amenable to numbers and based on fundamental physics, as is frequency. As a small correction, the argument of the log function in your formula should be F/Fo, where Fo is the starting frequency. The idea of F = 0 as a starting frequency isn't sound (pun intended). I also point out that when we add notes with each half tone, we are actually adding frequencies that are multiples of 1.0595 times the frequency of the previous note. The frequencies are not being added. If that were true, each frequency would be the previous frequency plus a DeltaF constant throughout the octave. The "human part" of this is in our feeling that each half tone added is "equal" interval as all other added notes, as in "equal temperament." An interesting experiment would be to have a person with perfect pitch identify the note he hears, of frequencies say from the low end of the piano to the top. Let's say his perfect hearing is perfect. I believe he'd do very well if he hears pure sine waves. Let's then plot his response, using a dot in a graph with both abscissa and ordinate as double axes, one for frequency and the other for "note." If you plot this, I'm sure you'd get a linear, straight line. If a real piano is used, there would probably be more scatter. But there would be no meaning to the locations between the dots. The above picture is what I was visualizing when I made my previous comments. But my error in looking at it this way is that pitch is not a numerical quantity with which you add octaves one on another. It's just notes, or categories. Regardless, thanks for catching that and helping me to understand it better.
  9. Exactly. It is 12 semitones higher. Additive, not multiplicative. What note above middle "A" is twice the pitch of middle "A."
  10. Sorry. Forgive me for my unnecessary elaboration. But yes, Peterson was a clever dude and was able to exploit the idea in applications that never saw it before. I bought the 490 Tuner about 20 years ago and now it's worth twice the price. The rotation speed of the disc, which is set according to their stable oscillator, differs for different ranges of frequencies, as you might expect, with the higher frequencies requiring faster rotations. The company then went a step further, with the iStroboSoft, used on ipads and computers, which doesn't have a mechanically rotating disc, but I believe LCD's are sequentially illuminated by updating the screen at the correct rate. It makes it look like there's something rotating, and the speed of that rotation is again set by the oscillator, with the strobe light determined by the musical instrument. At least that's how I think it works.
  11. Dave, sorry but I don't understand your last equation. Question: If your concertina is tuned to A 440, that means that the octave A above it is 880. Correct? Are you saying that the second note is not twice the pitch of the first note?
  12. Richard, I'm surprised that you haven't heard of the several applications of strobe lighting. There's a strobe instrument that can very accurately measure the speed of a rotating part. It's flawless and simple. You just change the frequency of the strobe until you see the part freeze in view. It can measure deviations from a mean, etc. Strobe techniques were used when they first figured out how different animals pace. You take a series of photographs of an animal walking or running in dim light, using a bright flash in a strobe. People were able to see very clearly the different kinds of gates horses and most other animals use. Until then, no human had a fast enough response to see the sequence of steps in a full gallop. People also learned much about how high speed projectiles penetrate targets. With the very high frequencies available, you can stop a bullet, then see it a mm later in its path and measure how fast debris is flying away. I believe the man most associated with it was Harold Edgerton, in 1931. His bulb is a discharge bulb, mostly powered by a large bank of capacitors, with responses in nanoseconds. The flash speed is normally so short, you need an inductor to slow down the discharge of the capacitors to expose the film, or CCD. I know because although some else in my company brought the idea into the company, I built a strobe system to measure the power of solar cells. They can illuminate the entire area of the cells with one-sun intensity, over a period long enough to electronically scan the terminal voltage from negative to greater than open circuit voltage over varying load and get the power curve. Edgerton was a good guy. I read he made all his patents free so that German and Japanese photo industries could rebuild themselves after WWII. I see the calculation you made and thanks for the correction. I failed to raise the number 2 to the appropriate power. Silly me. These results hold throughout the musical range. Best regards, Tom
  13. Dave, thanks for the comment and opportunity to clear up this issue. It can be confusing. The pitch of a musical tone is the frequency we perceive. Although it doesn't make sense to say so, it may be instructive to view frequency as what a tuning instrument "perceives." It works by physical principles. Our brains work by who knows what? Perception belongs to humans and frequency belongs to an objective nature, if we can call it that. Musical tones from real instruments contain multiple frequencies, called overtones, or partials, often with whole number ratios to a fundamental and in which case they are called harmonics. This is physics, Mother Nature. When we hear a musical tone, we perceive the fundamental frequency of the (mathematical) Fourier Series that represents the actual tone and call it the musical pitch. This is mathematics, and miraculously, it's also nature, as our brain/ear system perceives. There usually isn't any difference in the pitch we perceive and this mathematical fundamental. But if the tone is so heavily laden by upper partials, we progressively fail to detect the correct fundamental, to the point that we wouldn't call it a musical tone. We'd then call it noise. Thus the relationship between pitch and frequency is quite exact, but maybe not perfect. Your mention of the term "logarithmic" indicates you are confusing volume with loudness. Loudness, a perceived quantity, has a logarithmic dependence on volume, which is the physical measure of acoustic power per unit surface area. Loudness belongs to humans and volume belongs to nature. "Adding pitch multiplies frequency." I understand what you mean, but it's not an edifying description. Yes, each semitone is the 12th root of 2 multiplied by the preceding note. [Each upper half tone = (Start.Freq)*(2^1/12)]. That means when you multiply the root frequency in succession 12 times, you must arrive at twice the original value; i.e., (Orig.Freq)*[2^(1/12)]^12 = (Orig.Freq)*2. The cents definition is similar, and with the same geometric definition. Thus when you multiply the root by 2^(1/1200) you get one cent more frequency and for the entire octave, (Orig.Freq)*[2^(1/1200)]^1200, you again get (Orig.Freq)*2. This arises from the definitions of an octave (factor of 2), the division of the octave into 12 tones, and the definion of a cent being 1/100 of the tone interval. You might notice that your multiplication facto 1.059 = 2^1/12. I believe you call this logarithmic because the geometric operation means you add exponents and closed form solutions to cents calculations require logarithms.
  14. Richard, how did you determine that 0.1 cent is about 58 ppm? With the musical convention, an octave is broken into 12 tones, with each tone broken into 100 cents. There are thus 100 cents between each semitone. The question is, what are we measuring? Isn't it ultimately frequency? Thus, by its definition, one cent is 1/100 of the frequency interval between semitones and 0.1 cent is 1/1000 of the interval, or one part in a thousand. You can go to online calculators if you want to very that. Such a result applies along the whole range of musical pitch. The reason Peterson uses the strobe method is because it's so simple and foolproof, as long as you have a good frequency reference. The idea of strobe measurement goes back a hundred years, and for the Peterson instruments, an oscillator is used to accurately set the rotation speed of a wheel with markings. The signal from the musical instrument is used to strobe a light onto the rotating wheel. This will make the correct markings on the wheel appear stationary, and the circumferential distance from the zero along with the known speed of rotation tells you the frequency of the input signal. Here's from the manual of a Peterson 450 strobe tuner, which I have: - - - ACCURACY The exceptional accuracy of the PETERSON STROBE TUNER, MODEL 450 is due to the fact that all of the pitches are controlled by a single oscillator circuit of unusual design (patented) using components of the highest stability. The pitch is not affected by changes in power line voltage and the temperament is derived from precision counting circuits that are not subject to drift or variation. Recalibration should not be attempted in the field if an accurate standard is not available. Tuning forks can vary greatly depending on quality, temperature and humidity. Do not rely on these except for relative measurements. - - - From the manual of the iStroboSoft: - - - Calibrating iStroboSoft™ iStroboSoft will measure and display to within 0.1 cent accuracy throughout its full range. However, there may be instances when measurements do not match when compared to an external tuner. In such a case, the external tuner may be inaccurate, or iStroboSoft may be subject to biasing introduced by an inaccurate reference clock in its host device. This inaccurate reference clock inserts a 'bias' onto the audio signal during processing. This bias can be enough to sway an otherwise accurate measurement by as much as +/- 3 cents! To allow these host devices to be used to accurately tune instruments, iStroboSoft has a calibration feature which will independently allow it to calibrate to an external audio source and measure the offset of the bias to ensure an optimal measurement. This calibration is remembered permanently until you remove it. - - - There are calibration notes for Steve and others who use this software. - - - RAc, why end the discussion when it continues to bring forth all kinds of insights? Thanks for clarifying your position and I take it to mean you have no objections to my technical comments and that they were justified. Best regards, Tom
  15. RAC, you're right, there is confusion. I myself made the mistake of thinking that Steve's tuner was a dedicated instrument and not a software concoction in an iPad. My apologies there. On the other hand, Alex does say, "Oscillators are affected slightly by temperature changes though. Very accurate laboratory frequency references place the oscillator inside a thermostatically controlled oven." Thus, he was definitely talking about hardware, which justifies my comments. Then again, you say, "From my understanding, everything realized in software - no matter what algrithm they implement - must use the underlying hardware for reference." This also justifies my comments. So it seems there's confusion among all of us. I agree with your suggestion to have people conduct experiments and hopefully they will be done with enough rigor and explanation. Best regards, Tom
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