tárogató Remanufactured Part Deux

Discussion in 'Tárogató' started by jbtsax, Feb 1, 2012.

  1. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

    Joined:
    Jan 31, 2008
    Messages:
    349
    Likes Received:
    4
    But the top surface of a rolled tone hole is rounded rather than flat, meaning that the initial contact surface is very small without being sharp, and gets larger as more pressure compresses the pad.
     
  2. tictactux

    tictactux Distinguished Member Distinguished Member

    Joined:
    Mar 27, 2008
    Messages:
    1,462
    Likes Received:
    21
    That is all fine and true - if you have an ideal pad that "pops" back and knows no lasting impression rings. Which we all know is not the case.
    So I wager a bet that in the course of half a year or so, the average pad has a sealing area that is not much different from what it would be if the tonehole were flat (or only ever so slightly convex), with according forces required to close/seal the pad.
     
  3. clarnibass

    clarnibass

    Joined:
    Oct 5, 2008
    Messages:
    670
    Likes Received:
    1
    You're right... which is why regarding this specific issue, IMO non-rolled tone holes have an advantage. There are other reasons why companies made rolled tone holes, which some people think outweigh this issue, or they might not consider this issue at all.
     
  4. Taragot

    Taragot

    Joined:
    Jan 11, 2010
    Messages:
    12
    Likes Received:
    0
    What an interesting project!!!!!!

    I don't have the skills, tools, time and all the other things needed here, but my timis tárogató was motorboating on low c (not on b) due to some uneven toneholes and some minor leaks in the wood.
    I decided, I'll try to fix this with sugru (members of sotw will know what it is), without dissassembling the instrument. For the leaks in the wood it went very well, for the toneholes more or less, but it got better. Perhaps not the nicest stuff for wood repair, but really easy to use.
    Because it was discussed in one of the linked threads: I can play up to d, thanks to the zinner mpc I think

    Good luck with your further tárogató restauration !
     
  5. jbtsax

    jbtsax Distinguished Member Distinguished Member

    Joined:
    Mar 30, 2008
    Messages:
    1,409
    Likes Received:
    48
    Just an update to the progress on the wooden body segment of the tárogató project. Careful measurements were taken with telescoping bore gauges and a dial caliper to determine the bore size at the openings of each joint. The lengths of the joints were also measured and the measurements were used to compute the bore taper of each joint.

    As you can see from the illustration below, there is a minor difference between the tapers of the upper and lower joints. Whether this is intentional on the part of the instrument maker, or just a result of the low quality of the his work may never be known.

    One of the purposes of creating the detailed schematic is to pass on the dimensions to a professional "wood turner" who has agreed to make a set of two mandrels for a reasonable price. The mandrels will be wrapped with various grades of sandpaper to smooth the inside of the bore, and also as part of a holding jig for the joint while cutting and finishing the toneholes.

    [​IMG]

    The second illustration shows the "mismatch" in the middle tenon creating a gap. I haven't decided yet how to deal with this "birth defect". Any suggestions are welcome.

    [​IMG]
     
  6. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

    Joined:
    Jan 31, 2008
    Messages:
    349
    Likes Received:
    4
    Even good horns have these mismatches--both of mine have some degree of gaps/edges. I guess that it is not a major issue. On the Remenyi, there is a rather large gap at the mpc/top tenon. I put a temporary cork shim in to see if it made a discernible difference. It didn't.
     
  7. Gheorghe

    Gheorghe

    Joined:
    Nov 8, 2010
    Messages:
    227
    Likes Received:
    0
    Fantastic information, once again. Thank you!

    I took the same measurements on my instrument when I took off all the keys. In my case, the bore seemed to be way small in the top half of the upper joint, at least small when considering what I thought it should have been according to the taper I calculated based on the rest of my measurements.

    As I detailed in a separate thread, my octaves were hopelessly narrow, and I could not play the 2nd octave in pitch if my life depended on it, no matter what strength reed or what technique I used. I took the risk and gently adjusted that part of the bore, using a maple cone I turned on my lathe, with fine sandpaper wrapped around it. I used the taper I calculated, based on measurements of the bore up till the trouble area, to come up with the shape of that cone. Afterward I also went in with a "0000" steel wool to make the bore mirror-like smooth. Whether this is desirable or not I don't know, but it certainly did not hurt the sound.

    That fixed my octave 100%. Maybe I got lucky. I could have really ruined the instrument, since I was going in with the assumption that the taper should be consistent throughout the entire length of the instrument. Perhaps that is an incorrect assumption, now that I see the measurements you took. But at the time, I had nearly 0 information to go on, so I did what I had to do to get the instrument playing in pitch. It works for me now, and that's the only thing that matters to me. I also believe that in the case of taragot/tárogató, it's not exact science, and often the maker kind of hacks it.

    So I don't have any guilty feelings about modifying my bore.

    I'm really excited about your project and I enjoy your documentation of the process!

    George
     
  8. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

    Joined:
    Jan 31, 2008
    Messages:
    349
    Likes Received:
    4
    In theory you do want the bore as nearly conical as possible; in practice you sometimes have to tweak things for one reason or another, especially right at the top of the bore. If it worked then that's a happy end to the story. And yes, you do want the bore as smooth as possible for maximum acoustic efficiency. That being said, a slightly rough bore may be desirable if you like a bit of a warmer, softer sound, since that tends to attenuate the higher partials more than the lower.
     
  9. jbtsax

    jbtsax Distinguished Member Distinguished Member

    Joined:
    Mar 30, 2008
    Messages:
    1,409
    Likes Received:
    48
    It is helpful to know that even the better quality instruments have some less than perfect dimensions. My concern with the slightly larger than 1/8" void at the middle tenon is that it may be at the location of a pressure node and have a pronounced effect upon a given note.

    I am borrowing this idea from you as a way to work toward smoothing the bore. Once the instrument is playable, I can then use the same technique to slightly modify the taper if needed.

    Thanks for the compliment. I'm beginning to realize how far I have stuck my neck out by documenting the stages of this project especially since I have not done much of this type of work before. Fitting keys on a wooden instrument is really stretching my abilities since many are not easily swedgeable and the posts are in a fixed location (without major surgery of course). The rings especially are very unforgiving if anything has moved. Just cleaning the black goop off the body has changed the dimensions just enough to create a myriad of key fitting challenges! More detail on this will be provided on this as the work progresses.

    I am looking forward to meeting with Utah's clarinet expert in a few weeks to get his advice and recommendations with regard to the bore and tonehole restoration.
     
  10. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

    Joined:
    Jan 31, 2008
    Messages:
    349
    Likes Received:
    4
    I hope this instrument is worthy of all the work you are putting into it ;)

    If you are worried about that gap you could use car body or epoxy putty to fill it. My suggestion would be to put a bead around the inside at the bottom of the tenon receiver that is slightly too big, push the joint together (put some oil or cork grease on the bottom of the tenon to keep it from sticking), then take it apart, trim the excess roughly, let harden and finish. You can use powdered pigment to match the wood color if you wish. You can also use such stuff to line the bore and then sand out to desired dimensions if you want to try to match the diameter at the joint. But I would definitely wait until the end when you get the thing playing.
     
  11. Captain Simion

    Captain Simion

    Joined:
    Mar 12, 2013
    Messages:
    10
    Likes Received:
    0
    JBTSAX;

    Re: your post of 2-18-2012.

    Did you ever use the tapered mandrels on your instrument? Did you remove any significant wood to make it conical or did it just need polishing? Does it play with essentially correct octaves? The reason I am interested is that George changed the bore on his instrument to be really conical and had success with sharping the upper octave. I am tempted to do this to my TSO, but incrementally, with frequent reassembly/playing tests. Actually, I could not resist and did apply my homemade single flute reamer (1:18.5) to the TSO. After removing only a tiny amount of wood (and a lot of sandpaper-clogging crud), the lowest notes became much easier to play, and D at the bottom of the second octave is much sharper. It seems like progress.

    . . . C.S.
     
  12. jbtsax

    jbtsax Distinguished Member Distinguished Member

    Joined:
    Mar 30, 2008
    Messages:
    1,409
    Likes Received:
    48
    I am sorry to say I have yet to do that. The inside of the tarogoto is still a wild and wooly place. However, the octaves were quite well in tune. When I use the mandrels wrapped with various grits of sandpaper it will be essentially to smooth the rough surface as much as possible without removing a lot of material. One of the problems I discovered when plugging all of the toneholes on each joint and putting slightly pressurized air inside using my magnehelic was that tiny bubbles came through the wood everywhere! It seems the black goop originally put on the outside was not for cosmetics as much as it was to seal the wood to make it airtight. I am going to try to solve the problem by applying several coats of carnauba wax to the interior and then polishing the bore in order to seal the pores and tiny cracks in the wood. My theory is that the lower register will be more responsive if the body is made air tight. I am hoping that doesn't give it a brighter sound as I am fond of the warm dark tone that it presently gets.

    I will report more after I have found the time to get back to that project. It sounds as if we are dealing with many of the same issues on our respective Romanian tárogató shaped objects.
     
  13. kymarto

    kymarto Content Expert/Moderator Staff Member CE/Moderator

    Joined:
    Jan 31, 2008
    Messages:
    349
    Likes Received:
    4
    You are entering a world that one great acoustician (Art Benade) described as "three dimensional chess". If you study Rayleigh perturbation theory, you can actually predict what effect removing or adding material at any point will have on intonation of all notes on a horn. In a nutshell, constricting a bore will raise pitch if the point of constriction falls at a pressure antinode of the wave of the note in question, and will lower the pitch if it falls at a pressure node. Increasing the bore has the opposite effect. The amount of the effect will depend on how close the perturbation is to the node or antinode. Each note has nodes and antinodes at different places in the bore, so any perturbation will affect all notes, some in one way, some in the opposite way, and all to different degrees. So the risk is that if you don't know what you are doing, you can easily fix one note or several and make a number of others much worse. With conical instruments, you can easily ruin the whole instrument.

    In making shakuhachi flutes, even experienced makers often remake the bore (it is built up in hollow bamboo with a kind of putty, so it can be redone) thirty to fifty times until they are satisfied with it. I just want to warn you that you might be opening a huge can of worms, even more so since the intonation of an instrument is also heavily dependent on the design of the mouthpiece. It is, of course, much better to adjust a mpc to the horn than trying to adjust the horn to the mpc. Only after the mpc is optimized is it advisable to even think about changing the bore, with the knowledge that one can ruin an instrument with ease.

    When I first got my alto sax, I found it completely out of tune. I spent a lot of time putting different sized crescents in the tone holes. As I played, I kept adjusting, until to my surprise I had removed all the crescents except one. The moral here is that it was not the horn that was at fault, it was my playing. But my crescent involved only gluing rubber strips inside the tone holes, a completely reversible procedure. What you are talking about is not reversible.

    With that being said, it is absolutely advisable to smooth the interior of the bore--that will certainly make playing easier and response better. Generally speaking, doing this with sandpaper will slightly increase the bore diameter, but it will do so in equal proportion along the bore. Changing the cone angle locally can have very undesirable effects, and a straight cone is not always desirable: while theoretically only a cone gives perfect harmonic intervals, unavoidable real world compromises such as the space under tone holes, and the fact that the top of the cone is chopped off to provide a place for a mouthpiece, destroys this theoretical nicety. Makers almost always make local adjustments to the bore geometry to compensate for these realities--such as the cylindrical "necking in" at the top of the bore, and others as well.

    Just be aware of these things as you make your way.
     

Share This Page

Our staff's websites:


Loading...