Compress Audio Online Free — AI That Picks the Right Settings

Compression is the most misunderstood tool in audio. Engineer Guy's AI analyzes your track's dynamic range and applies the right threshold, ratio, attack, and release — then tells you exactly what it did and why.

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Correct Settings, Every Time

Threshold, ratio, attack, release — the AI picks them based on your track's actual dynamic range, not a one-size-fits-all preset.

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Plain-English Feedback

After compression, you get a breakdown: 'Your vocal had 18dB of dynamic range — compression was applied at -18dB threshold with a 4:1 ratio to tighten to 8dB.'

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Free to Start

Upload your first track and compress it at full quality. No credit card, no subscription required to start.

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Vocal, Music & Podcast

Different material needs different compression. The AI detects content type and adjusts accordingly — vocal glue, master bus compression, podcast leveling.

What Compression Actually Does

Compression reduces the dynamic range of audio — the difference between the quietest and loudest parts. When a vocalist hits a loud note, it gets turned down automatically. When they sing quietly, it stays where it is. The result is a more even, controlled sound where every word is audible and nothing jumps out as jarring.

This matters because uncompressed audio has a dynamic range that's too wide for most listening contexts. The loudest phrase in an uncompressed vocal track might be 20dB louder than the quietest breath. In a finished mix, that range needs to be much tighter — 6-10dB is typical for a lead vocal.

The 4 Compression Parameters (And What They Control)

Threshold: The level at which compression begins. Set at -18dBFS means the compressor only engages when the signal exceeds -18dBFS. Everything below that passes through unaffected. Setting threshold too high means the compressor rarely engages. Setting it too low and you're squashing every note equally.

Ratio: How much the signal is reduced once it exceeds threshold. A 4:1 ratio means for every 4dB above threshold, only 1dB comes through. A 2:1 ratio is gentle. A 10:1 ratio is heavy compression. Infinite:1 is limiting.

Attack: How quickly the compressor engages after the signal exceeds threshold. Slow attack (50-100ms) lets the transient (the initial hit) through before clamping down — preserving punch and snap. Fast attack (1-5ms) catches everything immediately — tighter control, but can sound pumping and unnatural on some material.

Release: How quickly the compressor stops after the signal drops below threshold. Too fast and you hear the compressor "breathing." Too slow and the compressor stays active through pauses, reducing the dynamic feel of the performance.

How to Compress Vocals vs Music vs Podcasts

Vocals in a mix: Moderate ratio (3:1-6:1), threshold set to catch 6-10dB of gain reduction on the loudest notes. Medium attack (10-30ms) to preserve consonant transients. Release set to track the performance — typically 40-100ms for sung vocals.

Full mix / master bus: Gentle ratio (1.5:1-2:1), threshold set to catch 2-4dB of gain reduction on the loudest sections only. Slow attack and release to preserve the natural dynamics of the mix. Over-compression on a full mix makes everything feel flat and lifeless.

Podcasts and spoken word: Higher ratio (6:1-10:1) to level out the inconsistent dynamics of conversational speech. Threshold set to keep consistent output level regardless of proximity to the mic. Some limiters apply a brick wall at 0dBFS to prevent any clipping on export.

The Beginner's Compression Mistake

Compressing too much. New engineers hear that compression "makes things sound professional" and crank the ratio up to 8:1 or higher with an aggressive threshold. The result is over-compressed audio that sounds flat, lifeless, and fatigued — every note the same volume, no sense of dynamics or energy. Professional mixing uses compression subtly: 2-6dB of gain reduction on most material, with heavier compression reserved for effect.

The second mistake: using compression to fix a performance problem. Compression reduces dynamic range — it doesn't fix a vocalist who rushes the beat, drifts flat, or has a weak consonant delivery. Those are performance issues that need to be addressed at the source or with editing, not compression.

Why AI Compression Works Better for Most Tracks

Setting compression manually requires listening carefully to the material, adjusting by ear, and understanding the interaction between all four parameters. For someone who processes tracks occasionally, this is a significant skill investment. Engineer Guy's AI analyzes the dynamic profile of your specific track and sets parameters accordingly — then shows you the exact settings it used so you can learn from each processing session.

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Frequently Asked Questions

Is audio compression the same as file compression?

No — they're completely different. Audio compression (dynamics compression) reduces the volume difference between loud and quiet parts of a recording. File compression (like MP3 or ZIP) reduces the file size. This page is about dynamics compression for mixing and mastering.

How much compression should I apply?

For most material, aim for 2-6dB of gain reduction on peaks. You can see this on the gain reduction meter in any compressor plugin — the needle should move 2-6dB on the loudest hits. More than 10dB of gain reduction usually sounds obviously over-compressed.

Should I compress before or after EQ?

The classic order is EQ before compression — you don't want the compressor reacting to frequencies you're about to cut. But many engineers use both: corrective EQ before the compressor, then tone-shaping EQ after.

Can I compress an already-mastered track?

You can, but results are usually poor. A mastered track already has its dynamics controlled — adding another compressor on top typically just makes it louder and less dynamic. Start from the unmastered mix if possible.

Does Engineer Guy apply compression automatically?

Yes — the AI analyzes your track and applies appropriate compression settings. The mastering module uses gentle multi-band compression for full mixes. The Mix Coach module applies vocal compression specifically tuned to your recording.