With all the talk about mechs lately, I've decided to put together a page on existing mechs. But before we get into that, we have to describe a little bit the different styles of playing bandura. There are basically two. The Kyiv style and Kharkiv style.
Here's a picture of me holding a Kyiv concert bandura:
Now, here's a picture of me holding a Kharkiv bandura (the first instrument I built). Notice that there are three hand positions for playing this type of instrument:
Now, let's compare the size and layout of the two instruments. Here's a picture of the concert Kyiv instrument with my half built Kharkiv instrument in front of it and a picture of the upper bridge or шемсток (shemstok).
Notice how much smaller the Kharkiv instrument is allowing you to almost cradle it in your lap. If you look carefully though, you'll notice that the soundboards are almost the same size. Also notice that the upper bridge on the Kharkiv instrument doesn't have anything in the way to interfere with the left hand playing where it wants.
The Kyiv instrument has Key change cranks (which are located elsewhere on other styles of Kyiv instrument check out here for some other instruments), tuning pins and the actual tuning J-hook, before we can actually play a string. If you were to try and play Kharkiv style on a Kyiv instrument, it would look something like this:
Not fun at all!
So, lets have a closer look at the mech. Here's a shot of the J-hooks on the Kyiv instrument:
What happens is, you turn the crank on top (or move a lever on other types, the mech works the same typically) and the J-hook moves down to pinch the same note in each octave on the instrument (e.g. you twist one crank and every F turns into an F#). On some systems there is a J-hook and an actual tacito which pinches the string.
There are seven cranks or levers usually set up to allow up to four sharps or three flats (or any combination of such). The "Nuts" on this system are adjustable for height and that indirectly adjust how much additional tension engaging the mechanism adds. How do the guts of this system work...glad you asked. Here's some pictures
Here we can see that each J-hook (which raises a string plus the semitone before it (e.g. the G mech raises the G to a G# and the F# behind it to a G)) is attached to a crank shaft. When that shaft twists, it pulls on the J-hook. All J-hooks for the same not in each octave are linked together with steel links. Here's an action shot of the mechs in motion:
(yes, next time I'll use a tripod, it didn't dawn on me to animate it until after I took the shots).
So, this mechanism works, and actually works pretty well, but in this format, is completely unusable on the Kharkiv instrument why? Because it's not curved. Now, Kharkiv instruments which a straight upper bridge have been made, but to me, it just isn't right and it's also less comfortable to play. Finally, this system is awfully tall and takes up a lot space.
Here's a picture of a common mech used on the Kharkiv instruments - it lives on the bridge (which makes it unacceptable to me for acoustic reasons). It write more but it's getting late and I've got a bike race tomorrow. I'll elaborate later. I'm sure the reader can find a host of issues with this: