Online Bass Instruction with Rusty Springfield
Key Signatures

Key signatures were invented as a kind of musical shorthand to indicate the accidentals. (as sharps, flats, and natural signs are called) Keys all contain identical interval patterns. Any given key contains a set number of sharps or flats, so, instead of writing them over and over, we use key signatures.

In your experiences as a professional bassist you will no doubt encounter a playing situation in which you will be asked to sight read a bass chart. (The term "chart" refers to a piece of music that contains the written music for the particular instrument for which it's written.) That means reading and instantly playing a part that you've never seen before. This doesn't have to be a traumatic experience. With thoughtful preparation you can develop the necessary skills to play the part accurately and with the proper feel.
Key Signatures Chart
As you look at a bass chart, one of the first bits of information you must glean is the key in which the piece is written. This will tell you a great deal about where to place your left hand so as to have the best access to the notes in that particular key, as well as the tonality of the "fills" you may need to put in.

You must have the key signatures memorized ahead of time, because there is usually very little time to contemplate a chart before the tune is counted off. Your command of this skill, and a few others, will greatly reduce the anxiety which you may tend to encounter the first several times you are asked to read a bass chart.

Tip: A simple way to remember the order of key signatures is to use your bass fingerboard as a guide.

 Your first string, assuming that you play a four string, is G. The key of G has one sharp. Your second string is D. The key of D has two sharps. Your third string is A. A has three sharps. (Are you sensing a pattern here?)

Your fourth string is E. E has four sharps. For those of you with five string basses, your next string is B, which has five sharps. There are two more sharp keys, which aren't represented by open strings on your bass. They are F#, which has six sharps and C# which has seven.

That's it for the sharp keys!

To remember flat keys, use the notes on the first fret. On the E string, the first fretted note is an F. The key of F has one flat. Up a fourth (which is the same as down a fifth), the first fretted note on the A string is Bb. The key of Bb has two flats. Up a fourth from there is Eb , which contains three flats. Continuing up another fourth we come to Ab. The key of Ab has four flats. The other flat keys are Db, which has five flats, Gb with six flats, and Cb (which is the same as B) with seven flats. As far as practical use is concerned, you will not often encounter tunes with more than four sharps or flats.

The above chart will help to familiarize you with what key signature placement looks like. It wouldn't hurt for you to get yourself some blank music manuscript paper and practice writing in various key signatures to increase your proficiency.
On to the next lesson: The Circle of Fifths