Łukasz Martynowicz

This was originally linked by Tom in a "MIDI latency" thread, but I think it should be linked here as well. http://www.public.co...g/PMA035061.pdf There is quite solid proof in this paper, that initial conditions in transient stage are very different from those in a steady oscilation phase and therefore a steady oscilation phase can have a completely separate description (which is in fact quite well researched and used in practice of reed/instrument construction). The missing "initial movement" problem does not in any way invalidate all other findings on the free reed behaviour that have been published and I personally don't have any objections to Tom's description of physics after the first few cycles (more precisely after Dana's "abrupt amplification" phase).

Just to confuse this thread a bit more, my latest accidental finding (rather unsuprising, but still interesting). I was testing my new reedpan yesterday and have tried a couple of accordion reeds on it. They are still unvalved, so when I have applied pressure, BOTH tongues of the accordion reed have spoken simultanously. In such conditions both tongues have smaller amplitude, the combined pitch is much more pressure dependant (note bends very easily, it is quite difficult to achieve a steady note) and the "reverse direction tongue" oscilates with small amplitude only (so it does not sink into the shoe), but it vibrates nevertheless. This "double reed" setting is much more sensitive to overall pressure and behaves very nice around a bellows reverse point giving almost uninterrupted sound [it starts to speak with very low pressures and cannot be chocked with sudden, high pressure push on the bellows. When one of the tongues was valved (with a masking tape) the same reed was very prone to choking with sudden bellows movement] This finding got me wondering if such effect could be usefull for some kind of "another type", new concertina… Probably somehow electric in nature as this setup has significantly lower volume (and is very air inefficient) and would require some sort of a "second step amplification", but almost continuous sound and note bending capabilities could prove musically usefull...

Then it is probably a rhetorical question if you know Korpiklaani? https://www.youtube.com/watch?v=cvbsrD3gDwo

But with Stuart's concertina in it

Nice work! I would like to hear this in a full metal band arrangement, along with drums, guitars and vocals

I use a large moleskine - it is very durable and large enough to actualy note something useful. With this larger version I can fit both ABCs and lyrics on the same page (or on the same spread) and actualy read the lyrics while I play.

I did listen to Stuarts version couple of times to get a clear view on why his version didn't had such impact on me as other versions prior to posting my opinion. But I see I must stress one thing more clearly: I don't think, that Stuarts version is bad or shouldn't be enjoyed And I truly think that this is a very fine piece of concertina playing. I was just trying to describe what differences made his version so different in its effect on me. Not to change anyone's taste or musical choices, but to just give some feedback from another angle - as a not native english speaker - as I think this changes a lot in percieving songs, focusing emotions more on music than on lyrics. And I must admit that not comparing it to NIN version is hard for me, as this is indeed one of the very few NIN songs I like and had listened to it over and over again at some point in my life, so it's now "embossed" in my mind very, very deep as a "blueprint" for this song.

I must agree with Ruediger on this one. But before I will add my two cents, I want to be clear - I definately appreciate your concertina playing here, what I have to say is about emotional content of the arrangement itself (and this is of course purely personal opinion). Hurt is one of my favourite NIN songs and the original Johny Cash version is playing right now as I'm writing this post (I didn't knew that NIN rendition was a cover). And I must say, that I haven't ever even focused on lyrics before (I'm not a native english speaker and I focus mostly on musical content when listening to songs in foreign languages) but still, both NIN and Cash versions have VERY strong choruses, and in both cases the overall construction of the melody tells a very strong emotional story with the music layer itself (NIN IMHO even stronger than Cash). For me, it could even be in Suahili or Chineese and it would make the exactly same emotional impact. Your version has no such effect - it makes me completely indifferent to the meaning of the lyrics. One reason for this is that you have dropped a very significant, steady beat in the chorus that builds up the tension and instead you slow down at the begining of the chorus, loosing the grip you have build up on the listener. And the second reason is that your vocals are very smooth and ornamental - very "polite" compared to strong and harsh "cry" in Cash and NIN versions. But nevertheless, I'm (as always) very glad to hear any non-traditional concertina repertoire, so keep it coming

There is HUGE audible difference between aluminum, zinc and brass reeds in "pure testing conditions". For my DIY project I have ordered sample reed from harmonikas.cz with shoes made from three different metals (and also three different aluminium reed "grades") and reeds with same geometry but with different properties of the shoe metal produce completely different sound spectrum. This spectrum can be of course modified to great extent by an instrument maker, but the exact same box fitted with two different sets of reeds will sound different. If your goal in learning to play bandoneon is to play "proper" argentine tango, then you should definately go with zinc plates - this very distinctive sound cannot be imitated even with large accordions with many different reed ranks. But if you are just looking for a good sounding "general use" instrument and prefer bandonion layout/ergonomics over accordion, there is no real point in zinc plates other than personal preference in tone. (But there can of course be further difference in response time and dynamics between different grades of aluminium reeds)

From my experience, clamping is not sufficient - my DIY concertina endplates had warped signifficantly even when screwed to the actual box. Stress caused by unequal drying of wood (or uneven distribution of this stress due to assymetric geometry etc) occurs whether or not the wood is clamped. It will just manifest when unscrewed, but the stress will be present in the wood nevertheless. As a sidenote: plywood warps too, but the amunt of warp for given thickness is smaller in plywood than in solid wood. And from my experience plywood tends to twist rather than bend in single direction (due to crossed grain direction in each layer).

I had a very serious latency problem with the first version of my MIDI software, and found out, that above a certain amount it effectively cripples the ability to play, because sound is generated a bit later than you expect it and this confuses brain too much. From my experience, this critical delay is about as long as it takes your finger to fully press the button (when you have normal force acting on the bellows) - the sound should play no later than when button is fully depressed. Otherwise you have to take this latency into account when fingering (on my Elise this applies to lowest, weighted reeds which are significantly slower to speak than the rest) which requires "forward thinking" and not just following the melody.

Well, this particular discussion, however deep and intensive it is, has very little to do with actual problems arising when building the actual instrument... The "multi instrument" approach which Jake suggested and which is already prooving worthy on the FB group is the main reason why this here forum is not the greatest place for this group's existence. I can remember at least one thread about designing and building a "modern anglo", which was overhelmed by people trying to discourage any modification to traditional Anglo concertina. This, by definition, won't be the case on a forum/group not focused on any single type of free-reed intrument. Similiarly to what you said "I myself don't see attending several forums with roughly the same (or widely overlapping) contents." - so why would a melodeon, bandoneon or accordion maker/player be interested in a concertina forum which even conciders chemnitzer concertinas as "outside of the scope" of this site? And facebook makes it an "automatic" participation for anyone already using this page on a regular basis for whatever purpose they do.

Ron, the whole point of me performing this experiment on the largest reed I have was to try to apply the flow ONLY below to the gap. This reed has a gap of about 1 mm height and tongue thickness at the edge of about 0.5 mm so you can easily flatten the straw below this width. I have performed this experiment once again, this time with bent straw and a lens, so I could observe reed behaviour a bit more precisely. This time I was varying the straw crossection height and here are some additional observations (the bottom edge of the straw is always touching the shoe): - if the straw height is less than the gap height the reed does nothing. - when the straw height reaches the combined height of the gap plus the tongue thickness (probably exceding it a tiny bit), the reed starts to vibrate. - when the straw height exceeds this combined height by a certain amount (but is still lower than double the gap height plus tongue thickness) the reed does not speak (at least not at a highest blow strenght I could achieve) - the assymetry of the flow is to small to propel the tongue. After this experiment my current intuition is that the only part of the reed that is responsible for the ability of the reed to start vibration is the "double V" (*) shaped section just at the tip of the reed and edge of the shoe and the Venturi effect at this small section, combined with bifurcation in the flow caused by the even slightest movement of the tip, deflecting the flow to the upper or lower surface of the tongue. Due to spring forces and tongue momentum this will be an increasing effect. One other thought: until this point we have assumed, that the axis of oscilation is always the same. But I think that it may be false assumption. I think that when the tongue is swinging enough to touch the surface of the shoe and close the gap completely, the pressure acting on the whole tongue surface moves the axis of vibration downwards. And because the pressure acts on the entire surface of the tongue and the initial mechanism acts only on the tip of the tongue, there will be some "wobbliness" in the tongue at this very point - it won't just bend at the mounting pivot point, but also around the center of percussion of the tongue. Think of it: this sudden axis change when the pressure gives the tongue "a kick" occures at the lowest point of the the already established oscilation but is not instantaneous, so the tip is already moving upwards in relation to center of percussion. So when the pressure pushes the tongue as far as it can (and we know from "choking" reed behavior that this is not a lot further than the thickness of the tongue) the initial oscilation, (this time around this new axis) opens the flow on the bottom, the pressure force acting on the tongue drops and the whole oscilating tongue axis moves upwards again. With few further cycles this initial oscilation wears off because the initial mechanism of bifurcation is no longer present (or significant) and the steady oscilation around the mounting point is established without any significant oscilation around the center of percussion. (*) "the double V" shape I think of is the crosssection shape at a tip, because the tongue and shoe are not infinitesimaly thin.

@Dana: your observation may sugest that after those 5-6 cycles the mechanism I seek gives way to the direct acting of the high pressure on the entire area of the tongue pushing it through the shoe. This is also why I was only able to get the reed oscilating above the shoe with the straw blow, getting only a low volume sound.

Well, as I'm more of an experimental than theoretical person, I have just performed a very quick and simple experiment which you can easily reproduce and which I think proove my approach definitively: I've taken my largest reed (the same I've mentioned earlier, which was choking under typical bellows pressure) and a drinking straw (flattened at the end to improve selectiveness of the jet produced), pointed it at the gap (*) and I blew hardest I could. I did manage to start the reed vibration and got a low volume sound. I was holding the reed in my hand in the ambient air, so there was no perpendicular pressure force on the tongue other than resulting from the jet of fast moving air and those two phenomenons I've mentioned eariler (or some additional turbulent effects on the bottom side of the tongue). (*) you have to hold the straw end with your fingernail very close to the gap and tongue.

@ Tom: Of course that all those various fluid dynamics effects come from calculations of the same equation, but used at different scales (both spatial and time) resulting in looking at a different geometry and airflow. I think that our missunderstanding comes from looking at the reed tongue at two different scales. You look at the reed as a divider between high pressure reservoire and low pressure reservoire and try to describe it at this "large" scale of an airflow. I on the other hand, focus only on the flow through the gap "magnifying" it. I'm not particularily interested in pressure differences between the bellows and the chamber and the steady oscilation phase, because I try to understand only the first cycle of movement, which we already agreed cannot be explained by this "large" scale (P1-P2)*A approach. It should be clear by now, that I think that the reed would close even when subjected to a very selective jet of air pointed only at the gap (prior to introducing this jet, the reed as a whole subjected only to ambient air pressure, equal both above and below the tongue).

I didn't say "basic physics" but "based on actual physics".

To be clear - I think that at the later stages of the reed oscilation the effects I have described coexist to some degree with the direct effects that the pressure gradient has on the oscilating reed.

Tom, all theoretical papers I've found on free reed analysis skip the starting period and focus on sound generating properties of steady oscilation. I also think, that slow motion, smoke airflow analysis is the only logical step in verifying my assumptions. Unfortunately I'm bound by the capacities of my workshop here which does not include high speed camera I'm also aware, that my explanations weren't as clear as they should be, and there are two main reasons for this: first is the language barrier and the second (more important) is that my times at university are long past and I haven't done serious math for more than a decade now. This is why I can only operate on simple illustrative experiments, observations and intuitions and must withheld from throwing any calculations into this discussion. Instead I did some digging and I think I have finally found a well-described principle that I was trying to ilustrate with my paper experments. It's called Coanda effect http://en.wikipedia.org/wiki/Coandă_effect and describes the tendency of a fluid jet to be attracted to nearby surfaces and is one of the fundaments for the lift force generation and numerous other fluid flow phenomenons. This combined with the third Newton's law makes the tongue to be atracted towards the jet as well and is what I think draws the tongue into the shoe at an early stage of the oscilation. The second principle which I have tried to describe with "the paper corner reed" example (in the part of airflow acceleration) is Venturi effect http://en.wikipedia.org/wiki/Venturi_effect which speeds the airflow and significantly lowers the pressure locally at the gap below P2, and in consequence increases the force generated by Coanda effect. Both of the effects above are generated only dynamically and are significant only when there is fast enough airflow, so as soon as the gap is closed (*) the tongue can spring back upwards against the pressure gradient. Because there will be some time needed for the airflow to reestablish after reopening of the gap, the tongue can have enough time to swing higher than initial position. In my opinion this combined effect is present also at a stable stage of the reed oscilation. This effect can also be present at the second (and third) point in the reed cycle, when the tongue crosses the bottom of the shoe, creating another gap - this time with the force acting upwards. But those both statements heavily depend on whether or not there is enough time for the steady jet to be formed at those later stages of tongue oscilation. Those effects are of course dependand on pressure difference P1-P2, tongue area and all sort of reed parameters, so they will be proportional to them in some way or another, so those "microscopic" effects may be in fact omitted in "macroscopic" description of the stable phase of reed oscilation, when the focus of description is mainly on acoustics of the free reed (as is done in all reed-related articles I could find on the web). I hope this time my point of view is finally clear enough to be seriously considered (either as true or false) as a coherent "theory" based on actual physics (*) there will probably be a slight delay between cuting the airflow and upward acceleration of the tongue because of inevitable turbulence below the tongue caused by a sudden cut-off of the airflow.

This is exactly why I think that (P1 – P2)*A is not a maximum force acting on the reed and an airflow through the gap must create force larger than this - you are seeking an additional mechanism that causes an amplified return in the first cycle, I seek the different mechanism which draws the tongue into the shoe in the first place, so the return mechanism is plain and logical. This force created by the gap airflow and it's relative value to the pressure applied to the tongue is easiest to observe on the lowest/largest possible reeds as the scale and frequency of movement is observable with a naked eye. If I experiment with my lowest reed on my tuning rig, this is what happens: 1) if I act on the bellows with normal force (pulling on the bellows, so I can observe the tongue motion above the shoe) the tongue is pushed into the shoe (just the thickness of the tongue below the edge, so the whole reed is flat) by the (P1-P2)*A force and does not speak, it acts only as a pressure valve. (by "normal force" I mean the force that makes treble reeds speak) 2) in order to make it speak, I must start the airflow through the gap with a much lesser force on the bellows (so that (P1-P2)*A is to small to draw the tongue into the shoe and in the same time is too small to keep it inside on the "agaist the pressure" part of motion). The tongue start to vibrate (at the stage in which it does not even sink into the shoe with all it's thickness and almost all of the oscilation happens slightly above the shoe) and only then I can increase the force on the bellows to make it louder. (I can recreate this reed-starting behaviour with weights attached to the bellows, so the eventual unsteady motion of the hand is not a factor in this) Another "paper experiment" for you to ilustrate that lift is generated: take a small piece of paper (I have used 5x10cm strip) and place it so it is horizontal (rest it on your finger) and has one (short) edge firmly held against your lower lip and then blow on it. As long as you blow there is an airflow speed difference between the upper and lower sides of the paper, so you can take your figer away and the paper will stay horizontal. The curvature of the paper is not important, it does not need to be an airfoil - an airfoil shape is necessary to divide the single pressure enviroment into two enviroments of different pressure but in this case we divide the enviroment by introducing the selective airflow by blowing just on the upper side(*). As soon as you stop blowing, the paper bends naturaly downwards, but you can lift it again by blowing (in this "freely hanging" starting position it does resemble an airfoil at the begining, but it becomes more flat the harder you blow and this shape is not essential to lift the paper as shown above in "resting on the finger" starting position). If you look at the closeup of the reed tongue at the gap, it looks very similiar to this experiment: due to the tongue/gap/shoe geometry there is significant airflow only on the single (lower) side of the tongue. And my above example with the low reed shows that this effect occur at pressure lower than needed to push the tongue into the shoe and that this is essential for the reed to speak. So I must disagree with you Tom on your statements that my illustrations are incorrect. My interpretation seems to be coherent with all different reed types: free, beating and double (and double oboe reed is the most close realisation of the "two sheets of paper" experiment, just with the hinge points on the oposite ends of sheets). And especially beating and double reeds cannot be explained by the approach in which (P1-P2)*A is the largest acting force, as this would just cut the airflow completely and hold the reeds closed as long as there is high pressure acting. And as you Tom admit, your interpretation fails to explain how the reed goes back against the pressure to higher position. Mine may of course be entirely wrong, but it does at least explain this and can be illustrated by all sort of different experiments. (*) to be perfectly correct there is a secondary airflow on the lower side of the paper to ensure the continuity of the flow speed gradient across the enviroment (the flow is laminar, no turbulence is created or necessary), and is caused by the upper airflow, but it is much slower than the upper flow.

Not to start any further debate, but just to clarify what I had in mind all this time, I have finally found a proper english name for what I have called a "suction effect" - I have previously used the direct translation from polish "zjawisko przyssawania" but it is called a Bank Effect in english: http://en.wikipedia.org/wiki/Bank_effect (as you can see now it is not a partial vacuum which makes drinking with straws work). This was my first physics debate in english and I can only apologise for not using proper english terminology (I have tried to find this name then, but have failed to…)

Thanks for your detailed explanation Tom!

First, the price: cost of a set of 62 DIX reeds from Harmonikas.cz for my Hayden was 400 euros. When it comes to wet/dry tuning, then it is a matter of tuning, not changing plates - dry tuning is just two very closely tuned (a spot-on or couple of cents apart) reeds playing the same note at once, while wet tuning are those same two reeds when tuned wider apart. But it is not a simple matter of changing the reeds if you want to modify the layout. You have strict chamber sizes on the other side of the lever when you press a button… So it is possible to make unisonoric instrument from bisonoric one, but the resulting layout could be even more bizarre. Reeds come in sizes, here is a size chart for harmonikas.cz: http://www.harmonikas.cz/admin/files/ModuleText/16-sortiment-sizes.pdf So if you want a strict layout after your modification, it might need tampering with chamber sizes also. That can lead to a mayour rebuild on the reedblocks/reedpan and depending on instrument may or may not be easy or even possible.

Depending on your budget and dedication, you have three options available: - starter Elise from Concertina Connection at 425$: 34 button, limited instrument, but perfectly capable of learning all of the Hayden techniques on it. And it can be traded in for a discount when upgrading to either of two of the following: - Concertina Connection Peacock at 2900$: 42 "almost standard" instrument. Not perfect because of those missing 4 buttons, but the cheapest, fully usable instrument. - Morse Beaumont at 3950$: 52 button instrument, the highest range available "off the shelf" with some very good opinions on the build, tone and action. All of the above are hybrid concertinas, with Peacock being the only one with flat mounted reeds (Beaumont has a mix of both reedblocks and flat mounted reeds). For the cheapest, traditionally reeded instrument you have to pay almost 6k$ and wait 6 years... You could also contact Bob Tedrow and ask him if he's willing to build one, he has done it before. There is a very little chance for finding something larger/older/more traditional second-hand, there were only few offers of used Peacocks recently.

The answer is beating reed. The difference is that in free reeds, the tongue swings freely through the opening in the shoe, while the beating reed is slightly larger than the opening that it's fitted onto so it is beating against it to cut the airflow.