While I tune my Tuba, on multiple occasions my sectional coach has called my section out becuase we do not hold down the keys aligned to the tunning slides of the key we are tuning. Is there a reason I have to hold the key down while I tune it?

Example: If I must tune my E Flat, why must I hold down my first valve (Key used for E Flat)?

  • I'm a brass player, and don't understand at all what you're saying! Could you clarify please?
    – Laurence
    Commented Mar 5, 2015 at 22:53
  • While I am tuning my instrument, many of a time my sectional instructor tells me to hold the key down for the slide I am tuning. EXAMPLE: If I tune my E-Flat note, I need to hold down my first valve as I move the slide and until I am done moving it.
    – The Man
    Commented Mar 6, 2015 at 2:02
  • 1
    Are you talking about adjusting the individual valve slides? This is normally a one-time setup, unless you have to move the main tuning slide a long way from its normal position to play with e.g. an out-of-tune piano. In normal use you're more likely to remove the valve slides to empty the condensation out! But yes, if this is what you're talking about, MattPutnam's advice below is good.
    – Laurence
    Commented Mar 6, 2015 at 13:38
  • I use a school instrument (so lots of people use it besides me) so it everyone changes it.
    – The Man
    Commented Mar 6, 2015 at 17:20

1 Answer 1


If the instrument is in good repair, then the inside of the slide should be air tight with the valve not pressed. Moving the slide would then cause there to be a pressure differential. At best, this makes it hard to accurately move the slide as the pressure wants to move the slide back to where it was, and causes a loud 'pop' when the valve is pressed and the pressure released. At worst, it can screw with the slide grease or valve oil if there's a little leak and all of the air jets through a gap in the slide or valve.

  • Frequently this pressure differential can cause grime to get sucked in and around your valves, even just at the edges where the seal happens, which can cause accelerated wear and force you to clean/oil your valves more frequently. Commented Mar 5, 2015 at 20:05

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