Audio Tips

Audio is often over looked and under-heard; careful attention to detail and listening lead to good solid audio on a video/film set/locations and in the studio.

To make a proper Mic selection, consider:

• type of mic -dynamic, condenser, ribbon
• pickup pattern
• size of diaphragm
• distance from mic
• wind, pop, spit screen change dynamic response

Each of these “colors” the sound recorded.

• Pickup pattern:
• Condenser Mics tend to be sensitive; have a typical sensitivity to higher frequencies – This is not a rule!! Think about a Kick drum condenser mic – it is certainly set for lower frequency response. However it can be said that it is “brighter” than a comparable dynamic mic – which would be “warmer.”
• Dynamic – warmer, needs no phantom power, Can create a heavier mid-range EQ.
• When selecting a mic think about: frequency response, whether you have a solution to a need or lack of need of phantom power, Size of diaphragm, type of microphone, pickup pattern.
• Shotgun= directional condenser
  create a “line of sight” with the mic such that it “sees” the talent’s voice but not the background.
  Micing from above just out of camera frame is often the best method.
  Rule: The more directional the mic, the more it will emphasize the echo in a small room.
  And so, long shotguns work well for exterior shots.
• If wind, then take the time to cover the mic with a windsock, zeppelin, windscreen etc.
• Two types of noise:
  Contact (translational) – a physical abrasion of the microphone surface by object (clothing) or wind creating a rustling distorted static, and
  Acoustic– background noise such as wind howling through trees or buildings.
• Pop screen – cuts down on consonance, and/or percussive voice signature
• More than one mic: distance mics 3X the distance between talent and mic. This will cut down on phase cancellations
• EQ tips for vocals, but can certainly be applied to other “instrumentation”
  • Top boost 6-12 kHz but be aware of sibilance.
  • 1-2kHz range boost will result in a honk-ing sound, not advised
  • Presence added with boost to 3-4kHz
  • Rolling off a touch of bass, makes the track sound a bit thin when soloed but in the mix will allow the vocal or other instrument to ride on top of other sounds.
• Bright – high end reverb can add sizzle
• Drums – careful dampening for unwanted sympathetic sounds.
  • Stereo mic drums with 2 additional kick and snare mics (4 mics total)
  • Bright = hihat; cymbal = condenser mic.
  • Mic 2” from head; 2” from the edge
• More Universal Mic Rules:
  • 5:1 The distance between adjacent mics should be 5 times the distance between mic and source
  • Always record the best quality you need at appropriate levels, as you can’t call for a “do-over.” If, for instance, you want a quieter sound in the final production, don’t record at a low level but instead, record at normal signal level and “fix” level in post. Like carpentry, you can always take away but it is difficult to add to…

EFFECTS

• Chorus – This can double a track; set up a stereo relationship; provide opportunities to pick off a channel and create different affects with one source sound. In general leads to a broader harmonic signature.
• Reverb applied across tracks can unify the mix but it is not a “real” situation – in a real situation each sound source would have a distinct reverb signature
• Using a high level of reverb coupled with a HF cut places a source away from listener
• Compression is almost always necessary when recording vocals
• Limiter = extreme compression
• Panning scenario

• Signal efficiency and amp/pre-amp. Keep an ear out for over saturation. Levels on pre-amps should be kept at about 75-85% so as not to introduce distortion
• When mixing: use pan, relative volume and frequency/dynamic processing in order to open spaces in which sounds may slip
• 3-D sound construction. Pan – x axis; volume and time processing z axis; freq. spread y axis (high freq. are perceived higher than low)

Music

• Guitars with single coil pickup take less acoustic space than humbuckers. Humbuckers tend toward a wall of sound…and thus a “live” sound.
• Boost freq. 2K-6K for improved presence, especially guitars
• Slow weak flange on hi-hats allow the frequencies to cut through the mix and improve presence as the flanged hi-hat oscillates through the mix
• Ducking with a compressor: input primary signal and in side chain input secondary signal. When the primary signal is present the secondary is attenuated or ducked so that the primary signal is more prevalent in the mix
• Reverberation is used to simulate a real acoustic environment. It informs the audience about space.
• Gating: by use of a side chain or gate, you control the tail or release of a sound. The gate does not allow unwanted signal to pass through.  A threshold setting determines what part of the signal is wanted and/or unwanted. For example: if you had a loud noise floor, you could impose a gate so that as soon as a wanted sound signal finished, the gate would close and the noise floor would attenuated to 0dB
• Reverse gate: the gated signal is only passed when there is no signal at the trigger input. And so, the two sounds are assured of being counterpoint to each other.

Acoustic guitar

• single mic pointed at junction of neck and body
• over-the-shoulder mic technique to best represent the player’s ear
• Think tonally as you mic. SM-57 gives you a wide mid-range sound. If you point a mic at the neck you get the strum and rhythm but also the squeaks from the strings
• Resonance from the body
• Separate two like sounding guitars by accenting their Bite (2-6kHz) with different EQ
• Compression on guitar is often used to create a long sustain

mrobin@unc