One of the most frustrating elements of bassoon playing is the mysterious leakage of air along the 8-foot long bore of the bassoon. Finding these leaks is critical to making your playing predictable be it pianissimo or fortissimo playing, not to mention playing in tune. Leaks in the instrument are by far the biggest problem and difficult to manage by band instrument repairmen who are totally clueless. Management of leaks by dedicated bassoon instrument repairmen are also difficult in finding the “sneaky” leaks that are especially common to older wooden bassoons and bassoons that have not been well-maintained.
Starting top down, the first leak is one that can be controlled (or not!) by the player’s embouchure. Many players are “passing gas” as they leak air while playing by not keeping a seal between the reed and their lips. Bassoonists can over-exert in fortissimo playing and occasionally out-gas on a fortissimo staccato. Those who gas us regularly are annoying especially if you are sitting next to them or if you are in a recording studio with a microphone within two feet of the player.
The reed is the next leak point. If your reed is flat and you have to narrow the blade and go to far, leaks can occur between the blades to the ruination of the reed. You might be better off looking for a narrower reed shape to help raise the pitch or review the methods for tuning in the Quick Guide to Bassoon Reed Tuning. Leaks can also occur near the first wire as a result of poorly constructed reeds and reeds can leak at the bocal for the same reason. The leaks above can be felt or heard if they are excessive.
The bocal can give us sneaky leaks. The most common is a crack or pinhole in the soldered seam that runs the length of the bocal. You may not be able to see it but you wonder why your bassoon is not playing right. This can be quickly assessed by plugging your finger on the big end and vent button and either sucking on the small end to check if it will hold suction or blow on it forcefully to see if it will hold air. By immersing the bend of the bocal underwater and sealing the end and button, blowing forcefully in the small end will show bubbles at the point where the air is escaping. Quick fix solutions will appear below.
A less common sneaky leak is again along the seam but at the tip of the bocal beyond the point where the reed penetrates into the bocal. It is common for the plating of nickel or silver to wear away over time exposing the soldered seam and weakening it to the point where it may crack the seam and cause a leak. This is the case all along the bocal if plating is worn away through wear and tear. The more common problem is abuse of the bocal by an accident where the bocal is bent or dented in the area of the seam. The bocal should be treated with great care. Never leave it on the bassoon unattended and a more common problem is the proper insertion of the bocal into the wing joint that does not strain or accidentally bend the bocal. And (duh!) don’t drop da bocal!
An additional sneaky leak can work its way from the inside of the bocal out as saliva for some individuals is so acidic that the solder is dissolved from the inside out. These individuals can also be identified by their fingers eating through the plating on the bassoon’s keys. We should all clean our bocals regularly but the acid folks should pay particular attention. A notable woodwind repairman suggests cleaning the interior of the bocal with baking soda to neutralize the pH balance
Unfortunately, bassoon cases traditionally have been made to store the bocal with the soldered seam facing downward against the bottom of the case leaving the remaining saliva in contact with the seam. This assumes that the bassoon case is laid flat. The seam always runs along the opposite side of the bocal button. If you are particularly anal about keeping the saliva off the seam drill a hole in the case for the bocal button can fit in to so the seam side is up. New cases commonly come with a bocal carrying case rather than at the bottom of the bassoon case where they can be damaged by those who throw their instrument into the case in a hurry or where the bocal is not secured in the case floating around at will.
The bocal cork can also provide a sneaky leak if it is cracked or has a very loose fit into the bocal receiver (well) at the top of the wing joint. Quick solution below.
A leak in the wing joint can ruin your day and it is so common it is surprising.