During the summer of 1979, I received a Heckel 12,000 series bassoon which was considered a "basket case" by the owner. The instrument had all the problems that one would normally expect from a new Heckel bassoon: lack of projection, low overall pitch level, stuffiness, and resistance. Certainly, it was not of the caliber that a bassoonist would desire for playing in an orchestral or professional situation. With all of the above problems in mind, I decided to service the bassoon with hopes of bringing about a major improvement in all of the areas mentioned above.
More than 40 hours total work time was spent in: (1) sealing the porous wood to bring the vacuum to maximum standards of one- minute on the wing joint and 30 seconds each on the boot, long joint, and bell, (2) re- seating pads, (3) paraffining pads, (4) contouring tone hole chimneys, (5) adjusting pad heights, (6) phrasing tone holes, and (7) voicing of the instrument. I supposed the instrument to now be in optimum playing condition and I certainly expected it to be free blowing and resonant. However, to my disappointment this was not the case. I now found that although some problems had been solved, there still was much resistance and stuffiness in the way the bassoon played and responded. In fact, the horn seemed to be even more resistant and in general had less good playing qualities than had existed before I worked on it.
Being quite frustrated, after doing everything that I routinely do, I recalled a conversation with Hugh Cooper in which he remarked that Hans Moennig was the only craftsman that he would personally allow to install water tubes. Mr. Moennig, based on his expertise and acoustical logic, has always stressed the importance of the design as well as the dimensions of each water tube. These comments led me to suspect the metal water tubes as being the possible cause of my problem. Upon removing the tubes and examining that part of the tube that extends into the bore, I observed that they were the original tubes from the factory, having sharp wire edges as opposed to the tubes with refined rolled edges installed by Mr. Moennig.
To extract the tubes, it was necessary to use "straight-fluted" hand reamers (nos. 2 thru 6) as shown in figure 1. I simply chose the appropriate reamer for each hole to fit tightly, and then wedged it securely by tapping the handle with a rawhide mallet (figure 2). Friction thus caused the tube to be locked to the reamer and a simple twisting and pulling motion allowed the tube to be pulled out (figure 3). Once the tube was out, I inserted it into a vise and backed out the reamer (figure 4). Sometimes it is necessary to insert the shank portion of the reamer in a vise and use a soft piece of metal such as aluminum to drive the tube from the reamer by tapping, being careful not to damage the flutes of the reamer.
After having removed the tubes, to my amazement I found that the instrument maker had left an abrupt wire edge, sharp enough to cut, on both the inside and outside part of the tubes (figure 5). This presented a situation detrimental to the proper functioning of the air column. Figure 6 demonstrates the movement of air as it encounters the sharp edge on the water tube producing perturbations and turbulence in the air column. As a result of this flaw in workmanship, stuffiness, lack of resonance and pitch distortion occurred. I carefully removed the wire edges with a machinist scraper by beveling both inside and outside parts of the tube (figure 7). After completing this operation, I then rolled the edges with 180 wet-dry sandpaper (wrapped around a drill shank) to give a rounded effect (figure 8). I also found it necessary to repeat the second step with 600 wet-dry sandpaper to obtain absolute smoothness of the edges (figure 9).
After replacing the modified tubes, the results were amazing. The instrument immediately became a more responsive bassoon. The overall intonation seemed to stabilize the projection was greatly increased.
In the past three years, I have removed sharp edges from the water tubes of a number of 12,000 series Heckels, along with some domestic bassoons, and found all of them greatly improved in response, projection, intonation, and ease of playing. I would recommend to anyone with metal water tubes to have them checked for sharp edges.