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Łukasz Martynowicz

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Everything posted by Łukasz Martynowicz

  1. Great material! Does anyone know, by chance, where can I get the dots for "Un-noticed Waltz"?
  2. That's exactly the mystery though - ALL tested cavities (this is a hybrid, I have more than two cavities of same dimensions), good and bad are 39mm x 14mm x 10mm and ports are 10mm diameter (and I also tested it with 12mm, 9mm, 8mm and 7mm ports). Graphs you see above are identical if I switch the reeds side to side or if I test any other identical chamber on the LH. I have two reeds (four tongues, four valves) and the problem always stays with LH side of the instrument for F3 note, with or without endplates, in both airflow directions and with all possible flips and orientations of those four tongues. Some of those chambers identical chambers are outer (basic two in question are both outer, but one of them is perpendicular to the closest outer edge and one is at 45 degrees) others are more or less inside the reedpan. Regarding "feeding into higher partials" - audible volume of the bad reed is louder than the good one (though dB meter stays at +/- 1dB spread between sides), so I figured that this energy has to go somewhere and on those graphs you have bit different distribution of dB levels of higher partials. You're the expert though, I'm just a more and more confused amateur builder looking for solution even more than the cause. Now the trick with increasing depth of the bad side chamber by 50% does change the spectrum enough for those notes to blend into the accompaniment well enough to pass as a flavour instead of the right out interruption, but this is a not ideal workaround.
  3. For your convenience, here are audacity screenshots, first is the bad one.
  4. There’s a .wav file with this problem attached to one of my previous posts. I have now switched to real time app and indeed the freq/volume graph is what I’m using. The problem is with missing/reduced second partial and shifting this energy into 2-4 higher ones (how many depends on the note in question) and as I wrote in previous post, it turned out this affects not only F3 but few other notes as well. F3 was most audible because the endplate emphasised this further in case of this note. And the problem is not with two reeds alternatively mounted in the same cavity, but a single reed alternatively mounted in two identical cavities. I just have two of those reeds, also identical, so I can swap them around. The problem stays with LH cavity. The strangest thing is, this is not because of anything with the reed itself.
  5. Ok. I have revisited the problem with a proper real time spectrum analysis app and have some findings and a good enough workaround but I still have no clue about why the difference is there. So, the problem does not originate in the endplate/action box, it just so happens that with F3 it emphasises the problem so much that it was unacceptably large and could not go by as "flavour". Now that I know what exactly is happening I could check all notes and as it turns out it does affect not only F3 (it is just the most offensive note), but assorted other notes, mostly on the LH side, with just a couple on the RH side, because lower notes are generally more affected by this. What is happening is that some notes have 2nd partial reduced and this energy goes into several upper partials, creating a gap and a "trumpet like" timbre. Only a single note, A3 is affected equally on both sides of the instrument. My best guess about why those differences are there is that either the amount of leftover reedpan material or exact chamber neighbourhood (layout of surrounding voids) interferes with some frequencies. So Alex, it turns out that this is related to what you wrote earlier, but it is not directly related to distance to outer edge, or anything else that I could pinpoint. At this point I simply accepted this phenomenon and moved to finding a workaround. What I've found worked well enough was to increase the depth of chambers in question by 50% (I've tested this in 10% increments) which promoted lower partials just enough while not muffling too much upper partials. I've fixed three notes at this point so it's a reliable enough solution. So now I have an instrument that requires that chambers on each side of the instrument differ substantially in order for two identical reeds to sound uniformly enough. Odd.
  6. As I wrote above, there are two F3 notes in that box, one on each side. When I swap reeds between sides the problem stays with the side of the instrument, not any of those two reeds (four tongues, this is a hybrid). That is my current theory, and I have made mass tests by adding putty to both sides, to either fix LH or recreate the problem on RH, but to no avail (but perhaps I have simply used too little added mass, such composite system probably acts differently to solid wood and I only added enough to cover the difference in geometry). But I figure this is a geometry issue if the endplate rather than mass of the endplate (the area of the „tongue drum” part). My current plan is to 3d print temporary endplates of the same geometry and work from there with carefull alterations in hope to pinpoint the cause and then apply results to the real endplate. But first I’ll try to butcher the endplate on this other box showing the same symptom, as it is a „single serving” 3d printed travel box made for this year’s vacations, now sadly behind me. I’ll report results of this butchering in a day or two.
  7. Only F3 reed and maybe G3 reedto lesser extent behave like this and perhaps F2 and G2 are affected but those do not have direct counterparts on the RH side so I can’t easily verify this. If I move this F3 reed to other four chambers of same dimensions the problem stays with the note, not the chamber, despite not being related to the reed itself. As I wrote, this problem stays with the instrument side, nothing else seem to affect this particular rouge frequency spike. Of course moving the reed around changes the tone as you would expect, but more on the bright-vs-cassotto dimension. Dana’s reedpan design indeed falsifies my intuition. Same as you, I have also tried fitting a dummy wall behind this pad, and same as you got no results.
  8. At first I thought so too, as I remembered discussions from years ago about those tonal differences you write about. But this particular quality does not change when I move this note around four different chambers on the LH reedpan. Now regarding what you describe I always wondered if it is because in traditional concertinas the back wall of the chamber is decoupled from the pan, while with inner chambers all walls are connected (either glued or carved from a single block altogether).
  9. Here is an audio source for the left part of the screenshot. 1st and 3rd is the bad reed, 2nd and 4th is the good one. ZOOM0001_MS120.wav
  10. In the pitch stability thread I’ve mentioned my misbehaving F3 note. I’ve done some more tests and I’m fairly certain that I’ve managed to norrow down the likely cause/causes. Attached is a screenshot of spectum analysis from Audacity: on the left are two repeats of LH/RH comparison (I have two F3s) with endplates mounted (a complete instrument) and on the right is LH/RH comparison without the endplates (only bellows and single reedpan/action board on the bench. It is the LH note that is problematic. Volume difference in the bench part is only partially caused by my failure to recreate exactly same pressure (this is large box, 8 2/3”, and is as such is VERY responsive), this note does sounds percievably louder during normal play, but the 2khz problem persists after decreasing the volume by decreasing padhole diameter. First a comprehensive list of all manipulations that do not affect this problem: reed and valve: this problem does not follow the reed when I switch reeds between sides chamber volume and coupling: chambers on both sides are the same and introducing a controlled airleak does not change anything chamber placement on the reedpan/relative to the fretwork: since this is hybrid Hayden I have 4 chambers of this size all over the reedpan and moving the reed around does not alter this particular tone quality. padhole size only affect overall volume baffles, of any kind, outer, inner, partial, full, even nearly airtight, do not alter this particular tone quality. This also includes antlers/hand placement. Now, the only manipulation that switches the side of the problem is switching endplates. But as I wrote above, it has nothing to do with reed placement relative to fretwork/hand. So, if I did not ommit something else, there is only one (and a half ) possible culprit. Both endplates share the same pattern, except for number of button holes and thus a volume of solid wood left in the LH endplate (this also means larger continuous (I’m not sure about the word here, entire endplate is obviously continuous, what I mean is „without any hole in it”) area in the center of the endplate). Other than that („and a half” ) there might be a slight difference in the thickness of shellac coating on the LH as I had to make some revisions to it. When tapping on the endplates they do make different sound, with LH being slightly lower. Now three questions to more experienced builders: have I forgot to test something else have you encountered a similar problem do you think that removing wood on the inside of the endplate will suffice or I have to bore another hole through the surpluss continuous area. This problem is the most audible with F3s, but I now think it also influences other notes slightly, up to G#3, just not to the point of dominating the chord/octave/side ballance so it have slipped my ear before yesterday’s investigation. It might also be a part of the reason why my F2-A2 range has a clear trumpet quality to it. One last curiosity, I have encountered the same problem of F3 standing out on entirely different box, a 7”, 3d printed hexagon with normal alluminum accordion reeds and not brass DIX reeds as in the box in question.
  11. Thanks! But as David wrote, I don’t see a benefit of this type of handle on an instrument without the bellows, especially when my handle is designed for sitting position. You already have the „flying hand” I was trying to achieve. That is unless Striso has accelerometer capabilities. In such case trading thumb freedom for additional degree of expression might indeed be beneficial and my handle leaves other 4 fingers virtually unconstricted.
  12. Currently I’m using Zoom iQ7 mic with iphone (I have been using Tascam im2 in a-b setup before). This is mid-side mic, so it gives a nice option to controll how much stereo/room reverb you want in your final recording. Depending on your iphone model you may need to use lightning extension cord due to interference with power supply. There are other such „field recorder” iphone mics, in a-b, x-y or mid-side configurations and with different price tag, so read some reviews/rankings first if you like such portable option.
  13. Regarding hand freedom without the strap, take a look at my handle design here: I’ve now tested it on two boxes, 66 button you see above and 45 button, 7 1/3” box. I’m nowhere near your level of play, but I’m now learning a piece that uses almost entire RH range of the 45 and it poses no fingering problems even when jumping from Bbs to G#s and D#, all while giving normal bellows control of a hand strap.
  14. Thank you very much for this hint, it might be a part of the problem, as this is a duet concertina, but as I wrote earlier, this problem does not follow the reed when I swap them between sides of the instrument. But maybe it is a significant enough part to it. What you wrote about wall height influencing the spectrum is in line with what I have observed with my lowest reeds when trying to improve response and pitch stability (this is when I had to and could go creative with chambers in an already built instrument). @Tom, yes, those were the conclusions on initial tongue oscilation mechanism. Without allowing it to happen by overblowing the reed, tongue acts as a simple pressure valve, exactly as I wrote before. I also second what Dana wrote about too thin/soft/weak tongues being prone to choking. I have a set of russian reeds from a cheap accordion, which are apparently made from a chopped tin can :D. Those are near impossible to set properly, they either choke if you play staccato or are so air hungry that it is pointless mounting them in concertinas.
  15. Exactly as Alex wrote, you can choke any reed, over any cavity, if you overblow it during the first half cycle. We have long ago established in discussions on this forum, that initial oscilation happens and has to happen entirely above the reedplate, otherwise the tongue sinks in the plate as you would expect from a simple valve and cavity resonance has nothing to do with it. Another question about irrelevancy of chamber shapes - aperture location relative to tongue tip makes all the difference for both reed response and strength of the tone. With long, thin chambers, location of the reed along the wall and aperture location also play significant role. In a simplified model of „only volume matters” those should not have any impact. But I think I know why we missunderstand eachother - for me the isolated pitch question is not really all that important or interesting, because I can tune deviations happening due to say valve choices or anything else with a simple file. It is the response problem, the timbre problem and the volume problem that is trully important when building an instrument, and with those, everything matters to lesser or greater degree and simplistic models don’t usually provide meaningfull clues when you encounter a problem. Now about burr/beating - it may help to know in this context that I’m not a native english speaker and finding an adequate translation for sound phenomena is difficult. But when I say that one partial gets amplified, I say that after looking at the spectrum in my tuning app (which sadly has no scale, only graphical representation). The spike is not present when testing without the endplate and is present with the endplate.
  16. I agree that „beating” is confusing. What I mean is that one higher partial is so emphasized that the reed burrs. I only ever encountered Helmholz calculations in free reed context in orthogonal form, so my bad here, but in this case it is even less acurate for free reed physics because cavity shape matters and matters a lot. Sorry, but you are trying to convince me, that when theory contradicts experience I should rely on theory instead of practice. When working to improve my largest reeds’ response I had to work within confines of available space, so I had to work with shapes I could fit in. Simply creating a cavity of calculated (and then verified on variable length cuboid tuning chamber) volume and mounting the reed on it did not work well. The response was better (but still not ideal) than small volume, but the sound was muted and nasal. Reshaping the cavity (with near constant volume) changed the tone completely, with different shapes having different exact result, ranging from soft and muted to powerful and deep). Moreover, changing the angle of completely constant cavity (to fit another one) relative to action board/padhole also significantly changed the response and tone. So I’ll stick to my experience for now and wait for a model that can explain those variations.
  17. I know this table and I know Helmholz model. What I try to tell you is that you can make the reed work perfectly well with non-orthogonal cavities that do not follow this model, thus the model is overly simplistic. Another example - I’m currently trying to solve the following problem: I have two F3 reeds in the box I’m building, both cavities have exact same geometries (classic Helmholz orthogonal), one causes beating, the other does not. The problem is not reed related nor valve related, as it doesn’t follow the reed when swapped. It is also not air leak decoupling related as you imply above in similar context. What is different between those sides is position on the reedpan relative to outer border and surrounding endplate geometry. Since you seem to understand reed physics way better than I do, maybe you can point me in a proper direction here? I have encountered the same problem in the other box and have indeed thought at first that introducing cavity leak will solve it, but it didn’t. This particular case has different reed, different valve, different cavity dimensions (coincidentally it is the same note, F3) and the spectrum is ok up until I secure the enbox screws. Any suggestions?
  18. I’ve mentioned chamber length and not volume for two reasons: first, this pretty much the only variable available when working with hybrid concertinas and anyone working with physical reeds imidiately learns, that they either work poorly or don’t work at all without the chamber, thus volume. Secondly, length and volume are two separate degrees of freedom when working with most difficult reeds - lowest and highest. As Alex wrote above, below certain reed size (this varies with particular properties of reed construction) reeds don’t speak at all with chambers that are too short, (this includes setups without chambers) so you have to first increase the length to make reed speak properly and only then you work with volume to shape the tone. With highest reeds, combined volume of chamber and air canal can prevent reed from speaking at all but you obviously cannot make chambers shorter than tongue length, so you have to decrase depth instead. Lowest reeds problem is also the gratest example why simplified, reductive models aren’t neither accurate nor useful. You can’t simply disregard chamber geometry, valve properties, padhole size, air channel length and action box geometry and still get something realistic. Each of those parameters not only shape the tone or set the pitch, but influence basic reed response. For example, you can stabilise the pitch of the reed and lower starting pressure by enclosing outer box, without having to increase chamber length. You also mention Helmholz resonator, but in my experience real reeds care very little about our simplistic math. I use non-cuboid chambers of quite unorthodox geometry for lowest reeds with great success, Alex tested L shaped chambers and some bass concertinas with layered reedpans rely on air canal volume (effectively another variant of L shaped chamber) to improve reed response. Regarding lowest pressure, I concur with what Alex wrote - with proper, oversized chambers my lowest reeds start basically immediately after lifting the pad under natural fully closed bellows springiness. They are responsive to the point where it is difficult to not make any sound with the pad lifted, so you can safely assume, that starting pressure in your model should aproach zero with increasing tongue length. Also, as Alex mentioned above, you have to account for reeds choking - if you apply too much pressure to stationary tongue, then instead of oscilating the reed will behave as a simple pressure valve.
  19. It varies and it varies enough that this effect is used for pitch bending by overblowing reeds on pull (yes, scale of effect depends on air direction relative to chamber) - lowest reeds (F2-F3) can be easily bend by -25 cents this way. With those lowest notes this effect is also heavily influenced by chamber length. In short chambers (reedplate length) this is so pronounced it is actually very difficult to play at stable pitch at all, while with 250% length chambers pitch is stable in the whole normal bellows pressure range, but still can be bent -5 cents when overblown. You can also affect this effect by changing padhole aperture, with smal holes being more bendable and large holes more stable. So your model must take all those parameters into account. Same effect is used by harmonica players, though they also modify chamber size and aperture on the fly.
  20. 7 1/3” to be exact. But I seriously doubt, that Wim would release a cheap box that would cannibalize Troubadour sales (if there are any, as this is the least reasonable Hayden on the market judged by utility to price ratio) so 34 buttons on Elise 2 seems like the most likely number.
  21. It is perfectly possible to fit 45 accordion reeds flat in 7” box. I have just printed a „field grade camping box” last week using reclaimed Elise bellows and reeds (which are in fact slightly oversized and the whole task would be a lot easier if they had standard scaling). All but 3 lowest of those 45 reeds are flat mounted, with only three lowest notes having my slanted chambers to improve response to instantaneous). I sincerely do not know why 7” Peacock has only 42 buttons and why Wim continues to design disfunctional Haydens when he clearly has the expertise to make all other systems properly.
  22. I see that Bob Tedrow is still listed - some time ago he has announced on his facebook page that he’s retiring and he won’t build concertinas anymore.
  23. I was thinking not about manufacturing method, but the underlying principle, because Goran's claim was that my design was "nothing new". As it turns out however, even the goals of Michael's design were entirely different. Thanks again for providing the link.
  24. Thank you! Just as I thought, it's a completely different beast.
  25. A question for the c.net collective mind: in a rather heated discussion on facebook group, Goran Rahm (known around here more than a decade ago from what I gather) has stated, that this type of handle design had been proposed earlier by Michael Bell in Concertina World 421 Nov 2001 (with drawings) and later in an article here on c.net (with photos). I have found the relevant link in this thread but the link is sadly no longer active and I can't find Concertina World article either. Does anyone here know where can I find drawings or photos of Michael's design? Just curious how close our concepts are.
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