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Odisha CHSE +2 Vocational Audio Video Technique study materials
Odisha CHSE +2 Vocational Audio Video Technique study resources

Odisha CHSE +2 Vocational Audio Video Technique: Microphones and Mixing

Odisha CHSE +2 Vocational Audio Video Technique · Work through your exam, one topic at a time.

All guide sections

Microphones and Mixing

This domain joins the two halves of every audio session: choosing and placing microphones, then combining their signals on a mixer. The exam asks you to justify a microphone choice by transducer, polar pattern and placement, and to explain console signal flow without confusing fader, bus and insert.

Microphones

  • Dynamic (moving coil): rugged, high SPL handling, no power needed, good for drums and loud vocals.
  • Condenser: capacitor capsule with preamp, more sensitive, extended high frequency, needs phantom power, used for studio voice and detail.
  • Ribbon: thin corrugated metal element, figure-8 by nature, warm but fragile.
  • Polar patterns: omnidirectional (no proximity effect, picks up room), cardioid (rejects rear), hypercardioid (more rear lobes, tighter), figure-8 (front and rear, maximum side rejection).
  • Proximity effect: cardioid and figure-8 microphones boost bass when close.

Placement rules

  • The 3:1 rule: with two microphones at different distances from one source, keep the second at least three times as far as the first to limit bleed and comb filtering.
  • Coincident pairs (X-Y) give mono compatibility; spaced pairs give wider stereo image; ORTF is a 17 cm, 110° compromise.

The mixing console

  • Gain before the fader sets the working level; faders balance; pan places into the stereo field.
  • Parametric EQ: frequency, gain and Q (bandwidth). Cutting narrow bands is safer than boosting.
  • Auxiliary sends feed monitors and effects; pre-fader sends are independent of the fader, which suits stage monitors, while post-fader suits effects.
  • Insert points patch dynamics and EQ into one channel; buses sum groups to the main mix.

Worked example. Source A is 20 cm from mic 1; mic 2 must be at least 60 cm from the source. Bleed into mic 1 is then 20 log(1/3) = −9.5 dB, about 9–10 dB down, which is audible separation.

Traps

  • Naming the wrong aux send type for monitor mixes.
  • Thinking a hypercardioid rejects everything behind it; it has a rear lobe.
  • Boosting EQ widely instead of cutting narrow problem bands.