Friday, August 28, 2020

Drums - Processing Overhead Microphones

Video Created by JOEL CAMERON - Transcribed by TOM BOWSER

NOTE: The snare sound in the overheads is a few milliseconds behind the sound in the snare mics. If the snare in the overheads competes with the signal in the close mics it can blur the perceived attack of the snare drum. By containing/reducing the snare sound in the overheads you can increase the level of the overheads/cymbals without causing a lack of clarity for the backbeat (snare and kick).

Overheads give a sense of space and dimension to the drum mix. The overheads also have a good part of the backbeat (emphasis on beats 2 and 4) of the snare and kick. You can see it on the OH channel strip meter. We want to control the components of the backbeat (mainly snare but also kick) in the overheads using a compressor. This will reduce the audible ratio of the backbeat (snare and bass/kick drum) to the cymbals in the overhead track. We will then hear more cymbals relative to snare and kick.

ADD COMPRESSION:

  1. Insert a compressor on the overhead channel tracks. We will use the Pro Tools Compressor/Limiter Dyn 3 in this example.
  2. Decrease the ATTACK time of the compressor to around 800 to 900 us. You decrease the ATTACK time by turning the ATTACK control counterclockwise. Experiment with an even faster attack time of around 400us.
  3. Reduce the release time, but not so much that you can hear the compressor working.
  4. Adjust the THRESHOLD until you see around 6 db of gain reduction occurring.

NOTE: We have reduced the output level of the overheads with compression. We can increase the level of the overheads if needed using the fader. Remember, the resolution of a fader is greatest at the top of its travel and nearest to 0db. You can also increase the output level of the track by increasing the output of the compressor.

If you have the level of the overheads too high in the mix you lose the clarity and definition of the close mic'd drums.

By containing the snare sound in the overheads (using compression) you can increase the level of the overheads/cymbals without causing lack of clarity in the backbeat.

ADD EQUALIZATION

NOTE: The following discussion of EQ is mostly relevant when close mics are used in combination with overheads. This approach to processing overheads would not be appropriate for minimalist miking techniques where there are no close microphones on the drums.

EQ: Use subtractive EQ rather than additive. When you use subtractive EQ you decrease/remove level at the equalizer which allows you to increase the fader level and get more fader resolution. The resolution (the incremental level changes the fader creates when moved) increases as the fader moves closer to 0 or nominal. Look at the numbers on the fader to verify this. You get greater level change given the amount of fader movement/motion at the bottom than the top of the fader movement.

  1. Engage the EQs HPF (High Pass Filter) using a 6 dB/oct slope. We want to remove/roll off most of the low frequencies present in the overhead microphone tracks. Our goal is to remove the low frequencies of the drums (not cymbals) from the overhead track.

    Most of the low frequency component of the drums should come from the close microphones used on each individual drum. We want to leave the cymbals within the overhead track sonically unmodified unless of course we purposely want to modify the sound of the cymbals.

  2. Begin at the HPFs lowest setting and slowly sweep to increase its frequency setting until you hear the low frequency component of the overhead track begin to decrease. An HPF setting of around 125 Hz is a good start. Use a higher setting if and as needed.

OR

  • Consider using a gentle "shelf" on the LF filter. Cut enough to take some of the body out of the drums (not the cymbals). Much of the body will come from the close mikes.

NEXT:

  1. Use the LMF filter and reduce at around 200 to 250 Hz. Soften and widen the curve using the Q control. This will reduce the punch of the kick and snare in the overhead microphones. We want a majority of the snare and kick sound to come from the individual close mics of the snare and kick.
  2. Consider adding some high mids (HMF) at around 8 KHz.
  3. Consider adding some high end (HF) using a shelf setting at around 6 kHz. Use the Q control to make the slope gentle. With a denser mix you may have to consider boosting the high frequencies to bring out the cymbals.