{"course":{"slug":"motion-and-audio","title":"Motion, Sound and Music","url":"https://addaly.com/learn/motion-and-audio","level":"intermediate","track":"create"},"lesson":{"slug":"eq-in-three-moves","title":"Three EQ moves that cover most voices","url":"https://addaly.com/learn/motion-and-audio/eq-in-three-moves","position":55,"of":72,"minutes":10,"answer":"High-pass below the speaker's fundamental, cut two to four decibels of mud between 200 and 400Hz, add a broad presence lift around 2 to 6kHz, and cut narrow while boosting wide.","keyIdea":"High-pass below the speaker's fundamental, cut two to four decibels of mud between 200 and 400Hz, add a broad presence lift around 2 to 6kHz, and cut narrow while boosting wide, because problems are resonances and pleasantness is a shape."},"body":{"format":"markdown","text":"## Cut first, boost rarely, and know which frequencies you are touching\n\nMost voice EQ is three moves. They are the same three moves nearly every time, and the reason they work is that they address three specific and predictable problems rather than a taste.\n\n**1. High-pass filter.** Remove what is below the voice.\n\nAdult speech fundamentals sit roughly between 85 and 180Hz for typical male voices and 165 to 255Hz for typical female voices. Below the fundamental there is nothing but rumble: traffic, air handling, footsteps, desk knocks, handling noise, and the low-frequency half of plosives.\n\nSet a high-pass at **80Hz for a low voice, 100 to 120Hz for a higher one**, with a slope of 12 or 18dB per octave. Sweep it upward while listening until the voice starts to thin, then back off. This is the single most useful filter in speech work and it is doing nothing to the voice at all: it is removing energy that was never part of it and that costs you headroom in every later stage.\n\n**2. Cut the mud.** There is almost always a build-up between 200 and 400Hz, from proximity effect, from a desk or a boundary reflection, or from the room. A **2 to 4dB cut with a moderately wide Q** is usually right. Too much and the voice becomes thin and telephone-like.\n\n> Figure: The three moves that cover most voices. Steps: 1. High-pass (80 Hz low, 100–120 Hz higher); 2. Cut the mud (2–4 dB, wide, at 200–400 Hz); 3. Presence (1–3 dB, broad, at 2–6 kHz); 4. Air, sometimes (a decibel of shelf above 10 kHz). Cut narrow and boost wide. A problem is usually a resonance, which is narrow; what sounds pleasant is a shape across a region, so a narrow boost sounds like the resonance it has just created. None of this restores energy a reflection cancelled: a notch is not attenuation, and boosting into one amplifies the noise in a band where the signal is gone.\n\n**3. A small presence lift.** Consonant clarity lives between about 2 and 6kHz. A gentle **1 to 3dB broad boost** in that region improves intelligibility noticeably. Above 10kHz, a shelf adds \"air\": worth a decibel or two on a good recording and worth nothing on a noisy one, because up there you are mostly lifting hiss.\n\nThat is the whole default. Most voices need nothing else.\n\n## Finding a resonance rather than guessing\n\nWhen something specific is wrong (a honk, a boxiness, a ring) there is a reliable method.\n\nTake a narrow band, boost it by 10 to 12dB, and sweep slowly across the spectrum while the voice plays. At the offending frequency, the problem becomes unbearable. Note the frequency, then **cut** there instead, by 3 to 6dB, with a moderate Q.\n\nThis works because a resonance is narrow and amplifying it makes it unmistakable. It is also easy to overuse: the sweep makes everything sound bad at high boost, and there is always *a* worst frequency. If nothing jumps out as obviously wrong, there is nothing to fix.\n\n## Cut narrow, boost wide\n\nA useful asymmetry. Problems tend to be narrow (a resonance at one frequency, a ring from one room dimension) so cuts can be surgical. What sounds pleasant tends to be broad, because tonal character is a shape across a region rather than a spike. A narrow boost sounds like a resonance, because it is one.\n\nPractical: cuts at Q of 2 to 6; boosts at Q of 0.7 to 1.4.\n\n## Minimum phase, linear phase, and what each costs\n\nAn ordinary EQ is **minimum phase**: changing the amplitude at a frequency necessarily shifts the phase around it. This is not a defect but a mathematical consequence of a causal filter, and it is what analogue EQ does. On a single voice it is inaudible and unimportant.\n\nA **linear phase** EQ keeps phase constant by processing with a symmetric filter, which requires looking ahead, so it introduces latency, and it produces **pre-ringing**: a faint smear *before* a transient, which has no physical analogue and can sound unnatural on percussive material.\n\nWhich to use: minimum phase for almost everything, and particularly for anything you are monitoring live. Linear phase is worth it when you are EQing two microphones on the same source that will be summed, because a phase shift on one and not the other changes how they combine. On a single voice track, reach for the ordinary one.\n\n## The point everybody skips\n\n**Fix it with placement before you fix it with EQ.** A boxy recording caused by a desk reflection has a notch in it, and an EQ boost aimed at a notch is amplifying the noise in a band where the signal was cancelled. Moving the microphone 20cm or putting a cloth on the desk removes the cause.\n\nEQ is very good at removing excess energy and very bad at restoring energy that cancelled. Cuts are cheap; boosts have a cost.\n\n## A worked starting point\n\nFor a close-miked voice in a treated-enough room:\n\n```\nhigh-pass       90 Hz,  18 dB/oct\nbell           280 Hz,  −3 dB,  Q 1.2\nbell          3.5 kHz,  +2 dB,  Q 1.0\nhigh shelf     11 kHz,  +1.5 dB\n```\n\nThen listen and change one thing. The mistake is to build a six-band chain because the plugin has six bands.\n\n## The free path\n\n**Audacity** has a graphic and a parametric EQ and a spectrogram view. **Ardour** ships with a capable parametric EQ and analyser. The **Calf** and **LSP** plugin suites are free, cross-platform, and professional in scope. **ReaEQ**, from Reaper, is free to use within Reaper's evaluation. **ffmpeg** applies EQ from the command line for batch work:\n\n```bash\nffmpeg -i in.wav -af \"highpass=f=90,equalizer=f=280:t=q:w=1.2:g=-3,equalizer=f=3500:t=q:w=1:g=2\" out.wav\n```\n\nA spectrum analyser costs nothing and is worth more than any EQ: **Voxengo SPAN** is free, and Ardour and Audacity both include one.\n\n## The limitation\n\nEQ changes the balance of what was recorded and cannot separate two things occupying the same band. If the fridge hum and the voice's fundamental are both at 120Hz, a cut at 120Hz removes both. Every EQ decision on a noisy recording is a trade rather than a repair.\n\nIt also cannot fix a room. A comb filter from a reflection has notches every few hundred hertz, and EQ can only apply a smooth curve to a jagged problem. You can reduce the most prominent tooth and you cannot fill in the gaps, because the cancelled energy is not attenuated: it is gone."},"check":{"question":"A recording sounds hollow because of a reflection from a desk 40cm below the microphone. An engineer tries to fix it with EQ boosts at the affected frequencies and the result is noisier without sounding fuller. Why?","options":[{"text":"The boosts are too narrow, and a narrow boost always reads as a resonance rather than as added body; wider boosts at the same frequencies would restore the missing energy.","correct":false,"tempting":"Q choice is a real guideline, but no width of boost can recover energy that cancelled."},{"text":"The comb filter's notches are cancellations, so at those frequencies the signal is absent and boosting raises only whatever noise remains there.","correct":true},{"text":"A minimum-phase EQ shifts phase around each boost, and those shifts are reinforcing the original comb filter rather than opposing it.","correct":false,"tempting":"Phase shift around a boost is real but small, and it is not why the boost fails to restore the missing content."},{"text":"The reflection arrives 2.3ms after the direct sound, which is within the window where the ear fuses the two into a single event, so the notches are perceptual rather than present in the signal and an EQ cannot act on them at all.","correct":false,"tempting":"Invokes precedence-effect fusion, which affects localisation; the cancellation is genuinely in the waveform."}]},"prev":{"slug":"double-system-and-sync","title":"Two devices, one event","url":"https://addaly.com/learn/motion-and-audio/double-system-and-sync"},"next":{"slug":"turning-the-loud-bits-down","title":"Compression does not make anything louder","url":"https://addaly.com/learn/motion-and-audio/turning-the-loud-bits-down"},"authorship":"Founder and series editor: Dr Mustafa Mun. Written by AI models to a written standard. Exam keys checked blind by a second model: 3,665 of 3,666 agreed. Academic review invited.","review":{"status":"Draft, open for academic review"},"cite":"Addaly (2026) 'Three EQ moves that cover most voices', in Motion, Sound and Music. Edited by M. Mun. Addaly. Available at: https://addaly.com/learn/motion-and-audio/eq-in-three-moves (Accessed: 13 October 2026).","licence":{"name":"CC BY-NC-SA 4.0","url":"https://creativecommons.org/licenses/by-nc-sa/4.0/"},"reader":{"schema":1,"title":"Three EQ moves that cover most voices","courseTitle":"Motion, Sound and Music","module":{"index":7,"slug":"shaping-and-mixing-sound","title":"Shaping and mixing sound"},"answer":null,"keyIdea":"High-pass below the speaker’s fundamental, cut two to four decibels of mud between 200 and 400Hz, add a broad presence lift around 2 to 6kHz, and cut narrow while boosting wide, because problems are resonances and pleasantness is a shape.","hero":{"kind":"figure","figure":{"t":"figure","label":"Figure 7.1","figure":{"type":"flow","steps":[{"label":"High-pass","detail":"80 Hz low, 100–120 Hz higher"},{"label":"Cut the mud","detail":"2–4 dB, wide, at 200–400 Hz"},{"label":"Presence","detail":"1–3 dB, broad, at 2–6 kHz"},{"label":"Air, sometimes","detail":"a decibel of shelf above 10 kHz"}],"title":"The three moves that cover most voices","caption":"Cut narrow and boost wide. A problem is usually a resonance, which is narrow; what sounds pleasant is a shape across a region, so a narrow boost sounds like the resonance it has just created. None of this restores energy a reflection cancelled: a notch is not attenuation, and boosting into one amplifies the noise in a band where the signal is gone."},"alt":"Figure: The three moves that cover most voices. Steps: 1. High-pass (80 Hz low, 100–120 Hz higher); 2. Cut the mud (2–4 dB, wide, at 200–400 Hz); 3. Presence (1–3 dB, broad, at 2–6 kHz); 4. Air, sometimes (a decibel of shelf above 10 kHz). Cut narrow and boost wide. A problem is usually a resonance, which is narrow; what sounds pleasant is a shape across a region, so a narrow boost sounds like the resonance it has just created. None of this restores energy a reflection cancelled: a notch is not attenuation, and boosting into one amplifies the noise in a band where the signal is gone."}},"blocks":[{"t":"h2","id":"cut-first-boost-rarely-and-know-which-frequencies-you-are-to","runs":[{"text":"Cut first, boost rarely, and know which frequencies you are touching"}]},{"t":"p","runs":[{"text":"Most voice EQ is three moves. They are the same three moves nearly every time, and the reason they work is that they address three specific and predictable problems rather than a taste."}]},{"t":"p","runs":[{"text":"1. High-pass filter.","b":true},{"text":" Remove what is below the voice."}]},{"t":"p","runs":[{"text":"Adult speech fundamentals sit roughly between 85 and 180Hz for typical male voices and 165 to 255Hz for typical female voices. Below the fundamental there is nothing but rumble: traffic, air handling, footsteps, desk knocks, handling noise, and the low-frequency half of plosives."}]},{"t":"p","runs":[{"text":"Set a high-pass at "},{"text":"80Hz for a low voice, 100 to 120Hz for a higher one","b":true},{"text":", with a slope of 12 or 18dB per octave. Sweep it upward while listening until the voice starts to thin, then back off. This is the single most useful filter in speech work and it is doing nothing to the voice at all: it is removing energy that was never part of it and that costs you headroom in every later stage."}]},{"t":"p","runs":[{"text":"2. Cut the mud.","b":true},{"text":" There is almost always a build-up between 200 and 400Hz, from proximity effect, from a desk or a boundary reflection, or from the room. A "},{"text":"2 to 4dB cut with a moderately wide Q","b":true},{"text":" is usually right. Too much and the voice becomes thin and telephone-like."}]},{"t":"p","runs":[{"text":"3. A small presence lift.","b":true},{"text":" Consonant clarity lives between about 2 and 6kHz. A gentle "},{"text":"1 to 3dB broad boost","b":true},{"text":" in that region improves intelligibility noticeably. Above 10kHz, a shelf adds “air”: worth a decibel or two on a good recording and worth nothing on a noisy one, because up there you are mostly lifting hiss."}]},{"t":"p","runs":[{"text":"That is the whole default. Most voices need nothing else."}]},{"t":"h2","id":"finding-a-resonance-rather-than-guessing","runs":[{"text":"Finding a resonance rather than guessing"}]},{"t":"p","runs":[{"text":"When something specific is wrong (a honk, a boxiness, a ring) there is a reliable method."}]},{"t":"p","runs":[{"text":"Take a narrow band, boost it by 10 to 12dB, and sweep slowly across the spectrum while the voice plays. At the offending frequency, the problem becomes unbearable. Note the frequency, then "},{"text":"cut","b":true},{"text":" there instead, by 3 to 6dB, with a moderate Q."}]},{"t":"p","runs":[{"text":"This works because a resonance is narrow and amplifying it makes it unmistakable. It is also easy to overuse: the sweep makes everything sound bad at high boost, and there is always "},{"text":"a","i":true},{"text":" worst frequency. If nothing jumps out as obviously wrong, there is nothing to fix."}]},{"t":"h2","id":"cut-narrow-boost-wide","runs":[{"text":"Cut narrow, boost wide"}]},{"t":"p","runs":[{"text":"A useful asymmetry. Problems tend to be narrow (a resonance at one frequency, a ring from one room dimension) so cuts can be surgical. What sounds pleasant tends to be broad, because tonal character is a shape across a region rather than a spike. A narrow boost sounds like a resonance, because it is one."}]},{"t":"p","runs":[{"text":"Practical: cuts at Q of 2 to 6; boosts at Q of 0.7 to 1.4."}]},{"t":"h2","id":"minimum-phase-linear-phase-and-what-each-costs","runs":[{"text":"Minimum phase, linear phase, and what each costs"}]},{"t":"p","runs":[{"text":"An ordinary EQ is "},{"text":"minimum phase","b":true},{"text":": changing the amplitude at a frequency necessarily shifts the phase around it. This is not a defect but a mathematical consequence of a causal filter, and it is what analogue EQ does. On a single voice it is inaudible and unimportant."}]},{"t":"p","runs":[{"text":"A "},{"text":"linear phase","b":true},{"text":" EQ keeps phase constant by processing with a symmetric filter, which requires looking ahead, so it introduces latency, and it produces "},{"text":"pre-ringing","b":true},{"text":": a faint smear "},{"text":"before","i":true},{"text":" a transient, which has no physical analogue and can sound unnatural on percussive material."}]},{"t":"p","runs":[{"text":"Which to use: minimum phase for almost everything, and particularly for anything you are monitoring live. Linear phase is worth it when you are EQing two microphones on the same source that will be summed, because a phase shift on one and not the other changes how they combine. On a single voice track, reach for the ordinary one."}]},{"t":"h2","id":"the-point-everybody-skips","runs":[{"text":"The point everybody skips"}]},{"t":"p","runs":[{"text":"Fix it with placement before you fix it with EQ.","b":true},{"text":" A boxy recording caused by a desk reflection has a notch in it, and an EQ boost aimed at a notch is amplifying the noise in a band where the signal was cancelled. Moving the microphone 20cm or putting a cloth on the desk removes the cause."}]},{"t":"p","runs":[{"text":"EQ is very good at removing excess energy and very bad at restoring energy that cancelled. Cuts are cheap; boosts have a cost."}]},{"t":"h2","id":"a-worked-starting-point","runs":[{"text":"A worked starting point"}]},{"t":"p","runs":[{"text":"For a close-miked voice in a treated-enough room:"}]},{"t":"code","lang":"","label":"Text","text":"high-pass       90 Hz,  18 dB/oct\nbell           280 Hz,  −3 dB,  Q 1.2\nbell          3.5 kHz,  +2 dB,  Q 1.0\nhigh shelf     11 kHz,  +1.5 dB"},{"t":"p","runs":[{"text":"Then listen and change one thing. The mistake is to build a six-band chain because the plugin has six bands."}]},{"t":"h2","id":"the-free-path","runs":[{"text":"The free path"}],"role":"free"},{"t":"p","runs":[{"text":"Audacity","b":true},{"text":" has a graphic and a parametric EQ and a spectrogram view. "},{"text":"Ardour","b":true},{"text":" ships with a capable parametric EQ and analyser. The "},{"text":"Calf","b":true},{"text":" and "},{"text":"LSP","b":true},{"text":" plugin suites are free, cross-platform, and professional in scope. "},{"text":"ReaEQ","b":true},{"text":", from Reaper, is free to use within Reaper’s evaluation. "},{"text":"ffmpeg","b":true},{"text":" applies EQ from the command line for batch work:"}]},{"t":"code","lang":"bash","label":"Bash","text":"ffmpeg -i in.wav -af \"highpass=f=90,equalizer=f=280:t=q:w=1.2:g=-3,equalizer=f=3500:t=q:w=1:g=2\" out.wav"},{"t":"p","runs":[{"text":"A spectrum analyser costs nothing and is worth more than any EQ: "},{"text":"Voxengo SPAN","b":true},{"text":" is free, and Ardour and Audacity both include one."}]},{"t":"h2","id":"the-limitation","runs":[{"text":"The limitation"}],"role":"limit"},{"t":"p","runs":[{"text":"EQ changes the balance of what was recorded and cannot separate two things occupying the same band. If the fridge hum and the voice’s fundamental are both at 120Hz, a cut at 120Hz removes both. Every EQ decision on a noisy recording is a trade rather than a repair."}]},{"t":"p","runs":[{"text":"It also cannot fix a room. A comb filter from a reflection has notches every few hundred hertz, and EQ can only apply a smooth curve to a jagged problem. You can reduce the most prominent tooth and you cannot fill in the gaps, because the cancelled energy is not attenuated: it is gone."}]}],"check":{"question":[{"text":"A recording sounds hollow because of a reflection from a desk 40cm below the microphone. An engineer tries to fix it with EQ boosts at the affected frequencies and the result is noisier without sounding fuller. Why?"}],"options":[{"text":[{"text":"The boosts are too narrow, and a narrow boost always reads as a resonance rather than as added body; wider boosts at the same frequencies would restore the missing energy."}],"correct":false,"tempting":[{"text":"Q choice is a real guideline, but no width of boost can recover energy that cancelled."}]},{"text":[{"text":"The comb filter’s notches are cancellations, so at those frequencies the signal is absent and boosting raises only whatever noise remains there."}],"correct":true,"tempting":null},{"text":[{"text":"A minimum-phase EQ shifts phase around each boost, and those shifts are reinforcing the original comb filter rather than opposing it."}],"correct":false,"tempting":[{"text":"Phase shift around a boost is real but small, and it is not why the boost fails to restore the missing content."}]},{"text":[{"text":"The reflection arrives 2.3ms after the direct sound, which is within the window where the ear fuses the two into a single event, so the notches are perceptual rather than present in the signal and an EQ cannot act on them at all."}],"correct":false,"tempting":[{"text":"Invokes precedence-effect fusion, which affects localisation; the cancellation is genuinely in the waveform."}]}],"order":[2,1,3,0],"why":null},"prev":{"slug":"double-system-and-sync","title":"Two devices, one event","minutes":10},"next":{"slug":"turning-the-loud-bits-down","title":"Compression does not make anything louder","minutes":11}}}