Polar patterns — which sound does the mic hear
- 1Omni — Picks up evenly from every direction. Common in lavs.
- 2Cardioid — Picks up the front and sides; least sensitive directly behind.
- 3Hypercardioid — Narrower at the front than a cardioid, with a small rear lobe.
- 4Shotgun — The narrowest at the front. How narrow it gets varies by frequency, so this is a concept drawing.
A polar pattern shows how well a mic picks up sound from each direction. For dialogue, you want a mic that hears the actor’s mouth well and hears less camera and lighting noise and less sound bouncing back off walls, so you put a directional mic on the boom. As you move off-axis on a directional mic, the sound gets quieter and its tone changes too, so the basic rule is to keep the front of the mic pointed at the mouth.
Shotgun vs. hypercardioid
| Feature | Shotgun | Hypercardioid |
|---|---|---|
| Front pickup | The narrowest | Wider than a shotgun |
| Best for | Exteriors, large interiors, when you have to keep your distance | Low ceilings or echoey interiors |
| Weak spot | In small rooms, reflections creep in and the tone gets muddy | Outdoors, it rejects distant noise less well than a shotgun |
| Length | Long, so hard to handle in tight spaces | Short, so easy under low ceilings |
Most production mics are condensers, so they need phantom power (48V) from the recorder or mixer to work. If you hear nothing, check the phantom power setting before you blame the cable. If you can only have one, decide by whether you mostly shoot outdoors or indoors; if you have both, swap them by location.
Lavs and wireless systems
- Lav — A mic about the size of a fingertip, hidden under clothing near the middle of the chest. Its distance to the mouth stays constant, so it’s strong on wide shots and walk-and-talks.
- Clothing rustle — The most common problem. Tape around the mic so the fabric can’t move, and agree with the costume department in advance on which garment it goes in and where.
- Transmitter — A small pack that sends the lav signal by radio. Mount it somewhere out of frame that doesn’t restrict movement, like the small of the back or the thigh.
- Receiver — Picks up the radio signal at the recorder and feeds it in. It must be set to the same channel (frequency) as its transmitter.
- Frequencies — Which wireless bands you may use is set by each country, so check your local regulator. Pick channels in advance that don’t clash with other wireless gear on set.
- Batteries — Transmitters are small and drain batteries quickly. Note when you changed them, and swap them early during breaks like meals.
Choosing by scene
| Scene | Reach for first | Also bring |
|---|---|---|
| Interior dialogue, low ceiling | Boom + hypercardioid | Lav backup, foam cover |
| Exterior dialogue | Boom + shotgun | Basket windshield, windjammer |
| Wide shot, walking far away | Lav + wireless | Boom as close as it can get |
| In a car | Lavs, plus a small mic hidden inside the car | A way to cut engine and wind noise |
| Interview | Lav and boom together | Decide in advance whether mics may show |
When you choose gear, think less about the single best mic and more about a setup where another mic still catches the dialogue if the boom fails. If the dialogue survives, other problems can often be fixed in post; if the dialogue is ruined, you have to re-record it in ADR, which costs time and money.
Wind protection — foam, basket, windjammer
- Foam cover — A sponge that slips over the mic. It cuts light indoor air movement and the wind noise from moving the boom.
- Basket windshield — Suspends the mic inside a hollow cylinder so wind doesn’t hit it directly. Standard for exteriors.
- Windjammer — A furry cover over the basket. On windy days it cuts the noise the basket alone can’t stop.
- For lavs — Use a small furry cover or foam. Hidden under clothing, the clothing itself can act as a windscreen.
Wind noise is big, low-frequency rumble, and it’s hard to remove cleanly in post. The recorder’s low-cut filter helps, but it doesn’t replace wind protection. Before you head outside, listen on headphones while trying different wind protection, and pick what works.
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