Audio Mastering for Acoustic & Spoken Word

Good audio mastering for acoustic music and spoken word does less than you'd expect: gentle compression, a light EQ touch, and a loudness target around -16 to -14 LUFS, so breaths, pick noise and room tone stay where they belong. In the free Vocal Cut mastering tool that's the Flat or Warm preset, Compression on Gentle, and the Apple Music (-16) or Spotify (-14) target. Budget about ten minutes per file, most of it spent listening.

That's the short version. The rest of this guide covers why quiet material needs a different approach from a trap beat or a festival drop, the exact settings to reach for, and what to fix before you master at all.

Why audio mastering for acoustic and spoken word should be lighter

Loud genres get mastered for impact. The EDM mastering approach and the hip-hop and trap approach both push toward -9 to -7 LUFS with firm compression, because a kick drum and an 808 are the whole point and the arrangement is dense enough to hide the squeeze.

A fingerpicked guitar, a solo piano, or one person talking into a microphone has nowhere to hide it. Crush the dynamic range and you hear it right away: the breath before a line jumps up to the same level as the line, the room hiss rises between phrases, and a quiet verse stops feeling quiet. What you're preserving here is contrast. The listener should still feel the singer lean in, or the narrator drop their voice for effect.

There's also less reason to go loud. Streaming platforms normalize playback, so a master at -8 LUFS just gets turned down to match everything else, with its dynamics already gone. The streaming loudness normalization explainer walks through the mechanics.

What you'll need

• A finished mix or edited recording. WAV or FLAC is best; a high-bitrate MP3 is fine. Mastering is the last polish, not a repair step.
• A clean source. If there's hum, hiss, or long dead air, deal with that first (see the prep step below).
• Decent headphones or monitors, and a quiet moment to listen at a normal volume.
• A modern browser. The tool runs on your own device, so your audio never leaves your device. No account, no upload queue.

Prep first: clean before you master

Any mastering chain, whether it's free audio mastering in a browser or a paid audio mastering service, raises the quiet parts of a recording. That includes the parts you don't want. Two quick passes make a real difference on spoken word:

1. Noise. Run voice recordings through the Noise Reducer in Voice mode, which uses an AI speech model (GTCRN) built for podcasts, interviews, and voice memos. For acoustic music use Music mode instead, which is spectral processing rather than AI and is aimed at hiss, hum, and broadband noise. The tool itself warns against running songs through Voice mode, and it's right. The AI pass takes a little while on longer files; there's a progress bar and an ETA.
2. Dead air. Long gaps in an interview or voiceover can be tightened with the Silence Remover. Skip this for music, because the space between phrases is part of the performance.

For a full record-to-publish walkthrough, the podcast recording and editing guide covers the steps before this one.

Steps: mastering audio online, free, for quiet material

1. Open the tool and drop your file in. Go to the free audio mastering tool and drag the file onto the dropzone. The Mastering Console loads and the Original readout shows your file's current integrated loudness in LUFS. Note that number, since it tells you how far you're about to move.

2. Pick a gentle genre preset. Under Genre preset you'll see Flat, Warm, Bright, Punchy, and Vocal-Forward. For acoustic guitar, piano, and singer-songwriter material, start on Flat or Warm. Warm adds a little low shelf and softens the top, which suits nylon strings and close-miked vocals. For podcasts and voiceover, Vocal-Forward lifts the 1 kHz and 4 kHz range where speech clarity lives, but it also bumps compression to Firm, which you'll undo in step 4, and narrows stereo width to 90%. Skip Punchy for this kind of material; it's built for drums.

3. Set the loudness target. Under Loudness target, choose Apple Music (-16) for podcasts, audiobook-style narration, and most acoustic releases. It lands on -16 LUFS, which matches Apple's published podcast guidance of -16 LUFS integrated (±1 dB). If an acoustic single is going mainly to Spotify or YouTube, Spotify (-14) or YouTube (-14) is fine too. Leave Club / Loud (-9) alone. The limiter at the end of the chain holds peaks at roughly -1 dB, so you don't have to set a ceiling by hand.

4. Set Compression to Gentle. The Compression slider has four steps: Off, Gentle, Firm, Aggressive. Gentle is a 2:1 ratio from a fairly low threshold, which smooths level jumps without flattening a performance. If you picked Vocal-Forward, pull it back from Firm to Gentle now. For very dynamic solo instruments, try Off and let the loudness target do the work, then compare the two.

5. Leave the rumble filter low. The Rumble filter runs from 20 to 100 Hz. The default is 30 Hz, which is right for most acoustic music. For spoken word you can raise it to 70–80 Hz to clear desk thumps and HVAC rumble. Don't go that high on an upright bass or a low piano; you'll thin the fundamentals.

6. Keep EQ moves small. The Equalizer has five bands: Low 100Hz, 250Hz, 1kHz, 4kHz, High 8kHz. For boxy voices, pull 250Hz down by 1–2 dB. For a dull acoustic guitar, add a dB at High 8kHz. If you're reaching for more than about 3 dB anywhere, the problem is in the recording or the mix, not the master. The guide to EQing a podcast voice goes deeper on speech.

7. Check stereo width. Most podcasts are voices panned center, so leave Stereo width at Normal (100%). If you picked Vocal-Forward, it will read 90%; that's fine for a centered voice, or drag it back to 100%. Widening a mono voice does nothing useful and can make it sound hollow on phone speakers. For a stereo acoustic recording, small changes are fine, but 100% is usually right.

8. A/B at matched level. Hit the Hearing: Mastered / Hearing: Original toggle. The comparison is level-matched, so you're judging tone and dynamics, not "louder sounds better." Listen for three things: do breaths jump out, does the room hiss rise between phrases, and does the quiet section still feel quiet? If any of them got worse, drop compression a step.

9. Export. Choose a format in the export selector and click Export mastered. WAV is the lossless default and the best choice for anything you'll upload elsewhere. MP3 is handy if your podcast host wants one directly. The tool re-measures during export and trims to hit your target.

Troubleshooting

Breaths got loud after mastering. Compression and a loudness boost lift everything under the threshold, and breaths live there. Drop Compression to Gentle or Off, or edit the worst breaths down in the mix before mastering. De-breathing belongs in the edit, not the master.

Hiss is more obvious than before. The master is louder, so the noise floor is too. Go back to the Noise Reducer, clean the source, then master again. Don't try to EQ hiss out with the 8 kHz band; you'll dull the voice or strings along with it.

It still sounds quiet next to other podcasts. Check the LUFS readout against your target first. If it matches, the difference is perceived, not measured: a thin voice reads as quieter at the same LUFS. A dB or two at 4kHz often helps more than more gain. The master too quiet guide covers the rest.

It sounds squashed or crunchy. You're probably on Firm with a loud target, or the source was already clipped. See why a master sounds distorted.

I need a different target, like -19 LUFS or -18 LUFS. The mastering tool's presets are -16, -14, and -9. For a custom level, master at -16 and then adjust in a DAW, or pick from the Volume Normalizer's LUFS targets, which match the same presets and include a Prevent clipping option that caps true peak. One caveat for audiobooks: ACX (Audible) doesn't spec LUFS at all. It asks for -23 to -18 dB RMS with peaks no higher than -3 dB, so check your file against those numbers, not a LUFS target.

Is an AI audio enhancer or a paid service better?

For this material, not necessarily. An AI audio enhancer can rescue a noisy phone recording, but on a clean acoustic take it often "improves" things you wanted kept: room ambience, finger squeak, the natural rise and fall of a voice. The software for audio mastering matters less than the restraint behind it. A paid engineer earns their fee on a complex mix or an album that needs consistency across tracks; a single podcast episode or a demo usually doesn't need that. The free vs paid audio mastering comparison lays out where the line sits.

Related

If you want to match a commercial release by ear, mastering with a reference track pairs well with everything above. For a podcast-specific walkthrough built around the -16 LUFS number, see how to master a podcast, and for picking a number in general, what LUFS should I master to. More tutorials live in the how-to guides.

Frequently asked questions

What LUFS should a podcast be mastered to? Most podcast guidance points to about -16 LUFS integrated for stereo, with true peaks at or below -1 dBTP. That's loud enough to hold up on phone speakers without squashing speech. In Vocal Cut's mastering tool, the Apple Music (-16) loudness target gets you there, with the limiter keeping peaks around -1 dB.

Should acoustic music be mastered quieter than pop or EDM? Usually, yes. Acoustic songs sound best with their dynamics intact, so -16 to -14 LUFS is a sensible range, compared with -9 or louder for club genres. Streaming services turn loud masters down anyway, so a quieter acoustic master loses nothing on playback and keeps the contrast between soft and loud passages.

How much compression should I use when mastering spoken word? Light. A gentle ratio around 2:1 evens out level differences between sentences without making every breath and mouth click as loud as the words. In the Vocal Cut tool, set the Compression slider to Gentle. If the speaker's level swings a lot, fix it in the edit before mastering rather than adding more compression.

Is free audio mastering good enough for a podcast? For most podcasts, yes. Spoken word needs clean audio, a consistent loudness target, and a safe peak ceiling, and a free browser tool can do all three. A paid audio mastering service matters more for music albums or problem recordings. Your audio never leaves your device with Vocal Cut, which also suits unreleased interviews.

Will mastering remove background noise from my recording? No. Mastering makes the whole recording louder and more even, which usually makes background noise more noticeable. Clean it first with a noise reduction tool, using a voice model for speech or spectral processing for music, and only then master. Mastering polishes a clean recording; it doesn't repair a noisy one.