Take the resonant head off the bass drum using a drum key to loosen the lugs holding it on. Start by placing a microphone a few inches inside of the bass drum. Point the microphone at the bass drum beater to capture more attack, or point the microphone away from the bass drum beater for less attack. Move the microphone closer to the beater to capture more attack and less bass from the bass drum. Move the microphone away from the beater to capture less attack and more bass from the bass drum.
Place the microphone a few inches outside of the resonant head of the bass drum. Keep the microphone at a 90 degree angle to the resonant head, and move it around the edges of bass drum. Experiment with the placement of the microphone to find the position that is most suitable for capturing the bass drum.
Place the microphone an inch or two inside of the port hole of the resonant head. Point the microphone towards the bass drum beater to capture more attack, or point the microphone away from the bass drum beater to capture more of the bass drum resonance.