Audio

Course 2 · Ch 3

Audio

Microphone types, recording environments, reducing room noise — sounding professional on any budget

The one thing viewers won't forgive Viewers will tolerate shaky video, a cluttered background, even bad lighting.
They will not stay for bad audio. Fix sound before everything else.

Chapter 1 covered which microphone to buy. This chapter covers everything that happens after you plug it in — how to position it, how to treat your recording environment, how to capture clean audio in an untreated room, and how to fix problems in post. Good audio is 30% gear and 70% technique and environment.

Microphone Types & Polar Patterns

Every microphone has a polar pattern — the shape of the zone it picks up sound from. Understanding this determines where you position the mic and why some mics suit certain environments better than others.

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Cardioid condenser (USB)

Cardioid — front-facing heart shape

Picks up sound from directly in front, rejects the sides and rear. Sensitive and detailed — excellent for voice in a quiet, treated room. Also picks up room reflections and background noise easily.

Best for: dedicated recording space, voice-over, podcast recording desks.

Untreated rooms: every echo and air-con hum comes through clearly.

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Dynamic (USB or XLR)

Cardioid — but far less sensitive

Less sensitive than condensers — requires the sound source to be close to the capsule. In return, it rejects far more background noise, room echo, and distant sounds. Forgiving in untreated spaces.

Best for: gaming commentary, untreated rooms, open-plan spaces, noisy environments.

Needs to be 5–15 cm from your mouth — a desk stand or boom arm is essential.

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Shotgun (hypercardioid)

Hypercardioid — narrow front lobe

Extremely directional — picks up a narrow cone of sound directly in front. Rejects almost everything off-axis. Mounted on a camera hot shoe or boom pole above/below the subject.

Best for: vlogging, outdoor filming, camera-mounted recording, run-and-gun.

Does NOT eliminate room echo — it still picks up reflections inside its narrow cone.

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Lavalier (clip-on)

Omnidirectional (most lavs)

Clips to clothing near the chest, 15–20 cm from the mouth. Omni pattern picks up everything equally — but proximity to the source means your voice dominates. Consistent level even when you turn your head.

Best for: presentations, interviews, walking segments, documentary-style content.

Clothing rustle, wind noise, and incorrect placement ruin lav recordings. Test before every shoot.

Polar patterns visualised

Pattern summary

Cardioid

Front-facing, rejects rear. Standard for desk mics, USB condensers, and dynamics. Most creator mics use this pattern.

Hypercardioid / shotgun

Very narrow front lobe. Maximum off-axis rejection. For camera-mounted or boom-pole use — must point directly at the speaker.

Omnidirectional

Equal pickup in all directions. Used in lavalier mics — the close placement compensates for the lack of directionality.

Microphone Positioning — The Biggest Free Upgrade

Moving a microphone 10 cm closer to your mouth can do more for audio quality than upgrading to a mic twice the price. Proximity matters enormously — especially for dynamic mics, which rely on close placement.

Mic type	Ideal distance	Position	Avoid
USB condenser (desk)	15–30 cm	Just below or to the side of mouth, angled up. Never directly in front — plosives ('p', 'b', 't') hit the capsule hard.	Directly in front at mouth level — plosive blasts
Dynamic (desk / boom arm)	5–15 cm	Must be close — dynamics lose quality fast with distance. Boom arm brings it close without obstructing the camera frame.	More than 20 cm away — sound becomes thin and distant
Shotgun (camera-mounted)	30–60 cm	Points at the speaker's mouth. Works at the typical camera-to-subject distance for a talking-head shot.	Off-axis — even 30° off ruins the pickup
Lavalier (clip-on)	15–20 cm (from mouth)	Clip to clothing at chest level, between buttons if possible. Avoid lapels — clothing movement causes rustle.	Under clothing — muffled; on lapels — rustle
Boom pole (overhead)	30–50 cm	Above and slightly in front of the speaker, angled down toward the mouth. Points at the mouth, not the top of the head.	Dipping into frame; angled at the forehead not the mouth

The pop filter — small piece of foam, huge difference

A pop filter (foam windshield or fabric screen) absorbs plosive blasts — the burst of air from 'p', 'b', and 't' sounds that cause a thump in the recording. A foam windscreen costs £3–5 and fits over most USB mics. A fabric pop filter on a gooseneck clips to your desk. Either eliminates one of the most common audio problems instantly.

Recording Environments — The Room Is the Problem

The biggest factor in audio quality for most creators isn't the microphone — it's the room. Hard, parallel surfaces (walls, floors, ceilings, glass, desks) reflect sound back to the microphone as reverb and flutter echo. This makes voices sound distant, hollow, and unprofessional. You can't fix a bad room in post — you have to treat it at the source.

Room treatment options

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Bookshelves (full of books)

Free (if you already have them)

Books are irregular shapes that scatter and absorb sound. A wall of bookshelves behind or beside you dramatically reduces reflections without looking like a recording studio.

The single best free acoustic treatment available to most people.

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Soft furnishings

Free (already in most rooms)

Sofas, carpets, curtains, cushions, and rugs all absorb high-frequency reflections. A carpeted room with a sofa records dramatically better than a bare wooden-floored room.

Record in the most soft-furnished room in your home — often a bedroom or living room.

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Duvet / wardrobe recording

Free

Recording inside a wardrobe full of clothes, or with a duvet draped over your head and the microphone, creates a surprisingly dead acoustic space. Used by professional voiceover artists in a pinch.

Embarrassing but effective. Many podcasters launched careers from inside their wardrobe.

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Acoustic foam panels

~£20–60 for a starter set

Wedge-profile or pyramid foam absorbs mid/high frequencies. Place behind and to the sides of the recording position. Doesn't need to cover the whole room — treat the first reflection points.

Foam panels don't absorb bass frequencies — for that you need mass (thick panels or bass traps in corners).

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Desk reflection filter

~£30–60

A curved panel of acoustic foam that mounts behind the microphone on a stand. Creates a localised dead zone around the capsule. Popular with voiceover artists and podcasters working in untreated rooms.

Reduces rear and side reflections reaching the mic — effective for cardioid condensers.

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Moving blankets / thick curtains

~£15–30

Hung on walls behind and beside the recording position. Not as effective as proper acoustic panels but significantly better than nothing. Double up for more absorption.

Hang behind camera view — they don't need to be in shot to work.

What room treatment can't fix

Acoustic treatment reduces echo and reverb inside your room. It does not block external sounds — traffic, neighbours, aircraft, and HVAC systems pass straight through walls regardless of how much foam you hang. For external noise: record early in the morning when traffic is low, close all windows, turn off HVAC, and use a dynamic microphone which is inherently less sensitive to distant sounds.

The Signal Chain — From Voice to File

Understanding how your audio travels from your mouth to the editor helps you diagnose problems at the right stage.

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Voice

Source

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Microphone

Capture

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Interface / preamp

Amplify (XLR only)

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Recording software

Capture to file

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Post processing

Clean & enhance

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NLE timeline

Final mix

XLR vs USB — what the interface actually does

USB microphones have a built-in analogue-to-digital converter — they plug straight into a computer. XLR microphones output an analogue signal that needs an audio interface (like the Focusrite Scarlett Solo) to convert to digital. The interface also provides phantom power (+48V) that condenser XLR mics require. USB is simpler; XLR gives more control, lower noise floor, and upgrade flexibility.

Recording Best Practices

Set your input level correctly. Record a test at your loudest speaking volume. Your peak should hit around –12 dB — not clipping (red), not too quiet (below –24 dB). Leave headroom for unexpected loud moments.
Record a room tone sample first. Before speaking, record 10–15 seconds of complete silence in your recording environment. This sample is used for noise reduction in post — it's the acoustic fingerprint of your room.
Turn off everything that makes noise. HVAC, fans, washing machine, notifications. Put your phone in another room. Close windows. The 30 seconds you spend silencing the environment will save hours of noise-reduction work.
Monitor with headphones while recording. Plug headphones directly into the mic or interface's headphone output. You'll instantly hear your own plosives, room echo, and level issues — before you've recorded an hour of unusable audio.
Record audio and video separately if needed. If your camera mic is mediocre, record the camera audio (for sync reference) and record clean audio on a separate dedicated recorder or your PC simultaneously. Sync in post using the clap or a clapperboard.
Do a full take before editing anything. Record the whole piece, then review. Stopping mid-sentence to fix a mistake resets your mental state and breaks the flow. Complete takes sound more natural than stitched ones.

Fixing Audio in Post — The Processing Order

Apply audio processing in this specific order. Each step depends on the one before it — applying compression before noise reduction, for example, amplifies the noise along with the voice.

Noise reduction first. Use the room tone sample you recorded to subtract consistent background noise (hiss, hum, air conditioning). In Audacity: Effect → Noise Reduction → Get Noise Profile → apply. In DaVinci Fairlight: the Noise Reduction plugin. Don't over-apply — too much creates an unnatural "underwater" sound. Aim to reduce, not eliminate.
High-pass filter (HPF) at 80–100 Hz. Roll off everything below 80 Hz — this removes low-frequency rumble (traffic, desk vibration, HVAC sub-bass) that isn't part of your voice but takes up headroom and adds muddiness.
De-esser. Tame harsh sibilance ('s', 'sh', 'ch' sounds) that condenser mics emphasise. Most NLEs and Audacity have a de-esser plugin. Target 5–8 kHz. Subtle settings — just enough to smooth the harshest peaks.
EQ (equalisation). Boost 2–5 kHz slightly for presence and clarity. Cut 200–400 Hz if the voice sounds boxy or muddy. Every voice is different — listen and adjust by ear rather than applying fixed settings.
Compression. Reduces dynamic range — brings up quiet moments, tames loud ones. Start with: ratio 3:1, threshold –18 dB, attack 10 ms, release 100 ms. Make-up gain to restore level after compression. Aim for a consistent, even voice.
Limiter (last in chain). A hard ceiling at –1 to –3 dBFS prevents any peak from clipping during export. Acts as a safety net — should barely trigger on a well-compressed signal.

Free tools that do all of this

Audacity (free, Windows/Mac/Linux) handles noise reduction, HPF, EQ, and compression well. The workflow: import your audio, get noise profile, apply noise reduction, then apply each process in order. Export as WAV, import into your NLE. Adobe Podcast Enhance (free, browser-based) runs AI-powered noise removal and voice enhancement in one click — genuinely impressive for quick fixes on location recordings.

Common Audio Problems & Fixes

Problem	Sounds like	Most likely cause	Fix
Echo / reverb	Voice sounds distant, hollow, like a bathroom	Untreated room, hard surfaces	Add soft furnishings, move closer to mic, use dynamic mic, use a reflection filter
Background hiss	Constant white noise behind the voice	Cheap preamp, low gain, electronic interference	Noise reduction in post, better interface, keep mic cable away from power cables
Hum (50/60 Hz)	Low electrical drone, constant tone	Ground loop, nearby power supply, fluorescent lights	HPF in post, move mic away from power supplies, use a ground loop isolator
Plosives (thumps)	Bass thump on 'p', 'b', 't' sounds	Mic directly in front of mouth, no pop filter	Add foam windscreen, angle mic below/beside mouth, add fabric pop filter
Clipping (distortion)	Crackling, crunchy distortion on loud syllables	Input gain set too high	Lower gain until peaks sit around –12 dB; can't fix clipping in post — re-record
Sibilance	Harsh, sharp 'ss' and 'sh' sounds	Condenser mic, bright recording chain	De-esser plugin targeting 5–8 kHz; mic placement slightly off-axis
Thin / weak voice	Voice sounds small, no warmth or body	Mic too far away, HPF cutting too much low end	Move mic closer, boost 100–200 Hz gently in EQ, reduce HPF frequency
Clothing rustle (lav)	Scratching, rubbing sound on movement	Lav on lapel, loose clothing, necklace contact	Use a lav clip/mount under clothing with a small loop of cable; remove jewellery

Chapter 3 Quick Reference

Best mic for untreated rooms: Dynamic (Samson Q2U ~£65) — rejects background noise
Best mic for treated rooms: Cardioid condenser (Rode NT-USB Mini ~£100)
Dynamic mic distance: 5–15 cm — must be close to work properly
USB condenser distance: 15–30 cm — off-axis (beside/below mouth, not in front)
Best free room treatment: Record in a wardrobe or bookshelved room
Record room tone: 15 seconds of silence before every session — needed for noise reduction
Input level target: Peak at –12 dB — never clip (red), never below –24 dB
Processing order: Noise reduction → HPF (80 Hz) → De-esser → EQ → Compression → Limiter
Free audio fix tool: Adobe Podcast Enhance (browser) for quick noise removal
Clipping: Cannot be fixed in post — re-record. Lower gain before recording.
Pop filter: £3–5 foam windscreen eliminates plosive thumps instantly
Monitor while recording: Headphones into the mic/interface output — catch problems live