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How to Fix Yamaha Bass Clarinet Octave Mechanism

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Yamaha Bass Clarinet Octave Mechanism

Identifying the Problem

The Yamaha bass clarinet octave setup is a constant source of frustration for many teachers. The mechanism falls out of adjustment so easily that it is almost never in alignment. Fortunately, it is very easy to fix.

Let’s observe the mechanism. These are the problems…

  1. The two pads are opening together (should be one at a time)
  2. The thumb has no extra free movement (A tiny bit of free movement is good)

If the small octave pad is sticking to the tone hole, then this is a different problem. You will need to take steps to prevent the pad from sticking. Or you will need to have the pad changed to cork, as it is in the video above.

Fixing the Octave Alignment

Step 1 – Fix the vertical alignment

Check the vertical alignment of the octave key. This is to ensure that the rocking mechanism won’t become detached every time you press the key.

The small rocking mechanism should rest with both end-points sitting centrally on their respective places.

Vertical alignment of the bass clarinet octave key.
The rocking mechanism on the Yamaha bass clarinet octave mechanism.

Step 2 – Diagnose Octave Key Issues

Instructions

To be sure that we are on the right track with we need to make sure that there really is something to fix. Or to put it another way, if you are unsure whether it is the octave mechanism that is causing your playing troubles, this diagnosis should help you to decide.

The problems that we are looking for in this step are these:

  1. The two pads are opening together (should only be one at a time)
  2. The thumb has no extra free movement (A tiny bit of free movement is good)

In order to diagnose these issues, we need to test the regulation of the octave pads with, and without, the thumb key depressed.

Using a feeler gauge, carry out these checks:

  • While the octave key touchpiece is held down, test the thumb and lower octave pad alignment. Both pads should close evenly and together, when the thumb key is pressed. If they are not closing together, use the adjusting screw to fix this.
  • With the octave key touchpiece depressed again, check whether the top octave pad is closing firmly. If it is not, skip over to step 3.
  • With the octave key touchpiece depressed, check that the thumb key has a tiny bit of free movement.

For a video on how to use a feeler gauge, watch this.

To test and adjust the free movement in the thumb key, move on to step 3 and skip to the 0:45 second mark in the video.

Step 3 – Fix the Double-Opening on the Yamaha Bass Clarinet Octave

Instructions

The reason for the octave key double-opening is that the octave key is opening up too far (normally it has been bent up). To fix this, the amount of movement in the octave key needs to be reduced.

Here is how to reduce the amount of travel in the octave key:

  1. Hold down the octave touchpiece with one hand.
  2. With the other hand, press down the opposite end of the octave touchpiece key.
  3. Pressing both ends of the key should bend the key down, and reduce the distance that it can open.
  4. If the key is not bending at all (or not far enough), move your hands closer toward the centre of the key, and try again.

Once the top octave key is sitting firmly on the tone hole (check using a feeler gauge as shown in step 2), you will need to check the thumb key.

How to check the thumb key:

  1. Hold down the octave key (touchpiece) and gently begin to push down the thumb key. The thumb key should move just a fraction (free movement) before the lower octave pad begins to move with it.
  2. If the thumb key has a lot of free movement before the lower octave pad begins to move, then we have bent the octave key down too far. Simply lift the top of the octave key. This will bend the key slightly, and allow more room for the pads to move. Doing this will reduce the amount of free movement in the thumb key.
  3. If the thumb key is pushing down the lower octave pad, and has no free movement at all, then it may be best to bend both ends of the octave key down further, until there is some free movement in the thumb key.

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