A trumpet, like any other brass instrument, is subject to temperature and other factors that will cause it to go out of tune. As a trumpet player, your instrument is so easy to tune that there is no excuse for not being tuned up and ready to go. Whether you are playing jazz, classical or rock music as a trumpet player, knowing how to tune your instrument is a skill that you just plain need to know.This is a quick and easy process that will make the trumpet, an instrument which can sound horrible when played out of tune, have that sweet and easy sound that we trumpet players love.
Grease all the slides on your trumpet. If they have not been greased in a long time, be very careful when removing them. Never use pliers or apply excessive force, as trumpet slides can dent or bend easily. You can buy a special type of grease made for brass instruments from music shops. Use this type of grease only, not Vasoline and definitely not Crisco!
Locate the main tuning slide on your trumpet. If you have a standard Bb trumpet (if you don't know whether your trumpet is a Bb trumpet or not, chances are great that it is), the tuning slide is the slide that runs along the first curve in the trumpet's tubing, on the mouthpiece end. The air comes from your mouthpiece, travels down the leadpipe and through the tuning slide, before it reaches the valves.
Find a piano, guitar or pitch pipe. It is good to tune your trumpet before you leave the house, because it is likely that you will be making fine tuning adjustments rather frequently, but you always want to start with the base. A pitch pipe will be good for this tuning purpose.
Play a "Bb" on the pitch pipe or other device. You can even download programs that will play notes on your computer in perfect pitch, and even "listen" to your trumpet to tell you if it is either sharp or flat. Still, you can't always have a computer in front of you, so it is good to learn to do it by ear. Now, with that note in your head, bring the trumpet to your lips while not pressing down any of the valves, and play a "C" on your trumpet. Because the standard trumpet is a "Bb" instrument, the trumpet's "C" is equal to a piano's "Bb."
Keep switching back and forth between the pitch pipe and your instrument, moving the properly greased tuning slide in or out slightly until the pitches match up perfectly. Pulling the slide outward makes the trumpet's tubing longer, and will thus cause the pitch to go flatter (or lower) when tuning your instrument. Pushing the slide in shortens the tubing, making the pitch go up (become sharper) when tuning a trumpet.
Know the general effects weather has on a trumpet's ability to stay in tune. Hot weather will cause the metal to expand slightly, and the pitch will flat, while cold weather causes problems with playing sharp, due both to your trumpet's tuning and your technique. Make sure to adapt accordingly.
Be flexible with the other musicians you are playing with, especially in small band settings such as jazz groups. Pianos at clubs and practice rooms can be out of tune more than you might imagine, and it is way easier for a trumpet player to just "tune up" rather than start complaining about how poor the piano is.
In orchestral settings, you will usually be tuning to a concert "A," which is "B" on the trumpet. But, because this is not a natural harmonic note on the trumpet, tune to concert "Bb" if at all possible.
Never force your trumpet's tuning slide in or out, as this could damage the tubing. Also, pressing down the third valve when adjusting the tuning slide helps in tuning a trumpet without putting too much pressure on the instrument.