Audio Compressor

Audio compression explained simply — bitrate, codec, and the trade-offs you actually care about

Every compressed audio file is a negotiation between file size and sound quality. The encoder listens to your audio, builds a model of what human ears can and can't hear in that moment, and throws away everything below the perceptual threshold. At high bitrates, what gets thrown away is genuinely inaudible. At low bitrates, you start losing things that matter — especially in music with lots of texture, reverb, or high-frequency detail.

The codec determines how clever that model is. AAC and Opus use better psychoacoustic models than MP3, which means they sound better at the same bitrate. That's the only technical thing you need to know.

Picking the right output format

MP3

Still the most universally compatible format on earth. Every car stereo, every Bluetooth speaker, every streaming app plays MP3. If you don't know what device your file will land on, MP3 is the right choice. Use 192 kbps for music, 128 kbps for speech and podcasts.

AAC

Better quality than MP3 at the same bitrate. Used by Apple Music, YouTube, and iTunes. 128 kbps AAC sounds about as good as 192 kbps MP3. Great for anything that'll be played on phones or Apple devices.

Opus

The most efficient modern codec. At 96 kbps it beats MP3 at 192 kbps for most listeners. The catch: not every player supports it. Works in browsers (Chrome, Firefox), Discord, WhatsApp voice notes, and most modern apps — but not car stereos or older hardware.

Bitrate guide — what each setting actually gives you

• 320 kbps MP3 — transparent for virtually everyone in virtually every situation. File is still 10x smaller than WAV but you won't hear the difference.
• 192 kbps MP3 — the real sweet spot. Indistinguishable from 320 kbps on normal headphones. Half the file size of 320 kbps.
• 128 kbps MP3 — excellent for speech, podcasts, audiobooks. Acceptable for music if you're not listening on good headphones.
• 96 kbps MP3 — noticeable quality loss in music but fine for voice content and very low file sizes.
• 64 kbps MP3 — voice only. Everything else sounds thin and artefacty.

The WAV to MP3 case — why it's so dramatic

WAV files store raw uncompressed audio at 176 kB/s (44.1 kHz 16-bit stereo). A 3-minute song is about 30 MB as WAV. As 192 kbps MP3, it's 4.3 MB. That's an 85% reduction with no perceptible quality loss. This is the single most impactful conversion you can make — it's where audio compression earns its name most visibly.

Re-compressing already-compressed audio — when not to do it

If your source is already an MP3 or AAC file, re-compressing it makes it smaller but at the cost of double encoding artefacts. Each re-encode introduces another layer of quality loss, even if tiny. For spoken word content this rarely matters. For music, avoid re-encoding if you can help it. If you have the original WAV or FLAC, always work from that — you get the full compression benefit with only one generation of quality loss.

Mono vs stereo — a simple gain most people ignore

Podcasts, voice memos, phone recordings, and interviews are recorded in mono even when the file shows two channels. Those two channels are often identical copies of the same signal. Switching to mono cuts the file size in half with zero perceptible change. If your content is speech, always check whether mono makes sense.