There are several methods of fixing timing issues with your marching ensemble. One method is to stand on the front sideline, directly behind the pit. Now, you are in the ultimate “hot spot”. From this position, you can watch the drum major and check the timing between the field musicians and the pit (standing here, you are essentially hearing the music as the pit members do).
Your first task in this process is to watch the drum major and see how well they are holding the tempo. Try to have a metronome to your ear and watch the major’s pattern. Besides checking for tempo maintenance, you can also check for pattern clarity and check to see where the major’s focus’ is. What section are they watching on the field and trying to keep in time? Which section to focus on will change from phrase to phrase. If the major feels like they are being pushed or pulled by the ensemble, have an instructor go to the back of the field with a metronome and speaker. Rehearse the musical phrase with the drum major conducting to the click of the metronome. This can be very revealing!
When the drum major is confident with their tasks, you can check the timing of the field percussion and winds. On the field, there are many situations that can affect timing. Here are just a few common problems for the field musicians: slowing down during direction changes in the drill, the battery slowing down during rolls or difficult technical passages, slowing down going into halts, they may be inconsistent with tempo changes, ritards, or accelerandos, or their distance to the front sideline may affect their timing (if they are too close or too far). During this process it is very important to make the pit aware of these tempo tendencies. During a performance they will have to listen back and adjust to all of these “issues” coming from the field.
Now that you know the timing tendencies of the ensemble you can head up to the press box or bleachers and address other issues such as balance, blend, and general effect.