A sparse "chart" with the form and some figures or a master rhythm part are different than a fully scored drum part. The first two require a lot of interpretation and addition. The fully scored part may in some instances require subtraction.
All arrangers and composers have different approaches when it comes to drum writing. Drummers have to use their taste and editing skills in making an arrangement work. One of the major issues for a lot of players is keeping their place and knowing where to go in a chart.
Many times a drummer will have no written chord changes or instrument cues to guide them. I usually keep my place by the harmony and form of a tune. Nashville has used a "number" system where the corresponding number of a chord in the progression is written into the part.
This allows the drummer to see and hear the progression. This kind of writing emphasizes the phrase which relieves the drummer of counting bars. A master rhythm part has all the rhythm section written into one or two clefs which provides the drummer with entrances and cues of what the other instruments are playing.
Reading a chart is a balancing act between interpretation and overplaying. It is critical to use your ears as well as your eyes. Here are few suggestions for reading a drum chart.
Learn to feel a four bar phrase, The Reed Syncopation book is written in four bar phrases, play three bars of time and hit the figures in bar four. Most Music is constructed in a four or eight bar phrase, big ensemble figures and transitions usually occur at the end of those phrases.
Learn musical form such as a twelve bar blues, AABA song form (32 bars) and the extended form of verse- chorus-bridge that is common in Rock. Listen to Music, the more tunes you know the easier it will be to sight read something.
Learn to scan a part by looking for repeat signs, first and second endings, DC, DS and coda's.
Last but not least is to remember the code. Nail the time and the form (road map) first and the ensemble figures second.
I would recommend getting a play along book to practice chart reading. The best one that I know of is Tommy Igoe's Groove Essentials. It has all the different
charts that I described and a band recording.
Following these simple concepts will put you on the road to being a more self assured reader. If you have any further questions you can contact me through my website.
The groove continues....