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Posts posted by DaveM

  1. I have a similar problem on the low A (draw only), in my case is seems to be associated with going out of tune too.  Anyway, I've heard that it can be related to the valves, or also just the height of the reed tip relative to the frame.  Hopefully one of the more experience repairers/maintainers will chime in too.

  2. I made a go at grabbing the waveform from my concertina (a brass reeded Lachenal) -- I was focused on the recording, so I hit D5 instead of A4, but this looks a bit different from the earlier post.   I'd say this is much more like a triangle wave + some extra modulation; you can see this in the power spectrum in that the even harmonics are down quite a bit relative to the odd ones.



  3. To me, I think it's often better to think of these things in the time domain.  "the spectrum is composed of peaks at multiples of a fundamental frequency of 1/T" is equivalent to saying "the waveform (in the time domain) is periodic with period T".   Anything that manages to produce a periodically repeating waveform will be perceived as having a pitch.  Savart wheels (https://en.wikipedia.org/wiki/Savart_wheel) don't have anything that is vibrating à la strings, air columns or reeds, yet still sound pitched.  So as long as the reed manages to make a periodic disturbance in the air, the sound will have harmonic overtones.


    Even for plucked strings, it's just as good to think of what is going on is something like this:  the string is plucked at a point, two disturbances, one in each direction along the string, propagate away from it, they bounce off the nut/bridge and so on.  The amount of time it takes for the wave pulse to make  a complete round-trip is the fundamental period.  It's that we get this kind of periodic behavior that gives the sound its pitch (of course you won't have the pulses run back and forth along the string without change unless the stationary modes have frequencies that are integer multiples of the fundamental...) Anyway, I find it useful to think this way in order to not get too hung up on the fact that the vibrational modes of reeds don't have harmonic overtones, and, as far as I know, the higher order vibrational modes aren't relevant for the sound production of the reeds.


    I wonder if anyone has tried exciting a free reed without using airflow.  One could take a steel reed, stimulate it with a magnetic field at the correct frequency and see what a reed sounds like without airflow through the reed frame.  I'm still unclear whether we "hear the reed vibrating" or "hear the reed chopping the airflow through the frame".

  4. It's a shame that a person comes to Concertina.net and gets directed to an accordion!


    I hadn't heard "continental" for CBA (I always thought it was chromatic). Looking into it, I found this video of a very compact one:


    same author has a nice video on English concertina too 



    I can hear the difference between accordions and concertinas, so that might be something else to think about, even if it is only to make sure you get an instrument that makes a sound you really like.





  5. I think it is a bit more than just mechanical, especially for someone completely new to music. Playing scales and arpeggios allows you to associate the muscle movements with the sounds in the context of a key. Yes, tunes do this too, but then you to divide your focus between multiple aspects of the music. Presumably, for some people this focused aspect is helpful, for others it may be unnecessary.

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