Preparing audio before upload: loudness, clipping, and the 15 MB limit

May 2026 · 5 min read

Upload interfaces want you to drag and drop. That is fine when the file is healthy. When it is a brick-walled SoundCloud rip named final_FINAL_v3.mp3, separation quality suffers before the model even warms up.

Check levels before you upload

Modern masters are loud. Separation models do not care about your LUFS target — they care about whether the waveform still has shape. Hard clipping flattens peaks and creates harmonics that look like extra vocal content or noise. If your DAW's meter is pinned red the whole chorus, expect mushy stems.

You do not need to remaster the song. Light gain reduction (a few dB) on an overly hot file can help. Do not "fix" quiet recordings by cranking gain into distortion; quiet and clean beats loud and clipped.

Fit the 15 MB / 5 minute box

SongRemoveVocals accepts MP3, WAV, M4A, and FLAC up to 15 MB and 5 minutes per track. A three-minute WAV at 44.1 kHz/16-bit is usually well under the limit. A five-minute stereo WAV can exceed it — export 320 kbps MP3 for the upload test, or split the song.

If you are preparing specifically for separation quality, read WAV vs MP3: a high-bitrate MP3 under the size cap often outperforms a truncated WAV someone squeezed to fit.

Trim silence and intros

Long silent intros and crowd noise at the top of live tracks consume duration without adding value. Cut to the section you need — especially if you are rationing daily minutes. Ten free minutes per day (UTC reset) goes further when you are not processing ambient room tone.

One generation, one upload

Every re-encode adds artifacts. Export once from your source app, upload that file. Avoid routing through messaging apps that transcode attachments "for convenience." We have seen plenty of separations fail because the input was a forwarded WhatsApp audio file.

Quick pre-flight checklist

Source is the best version you have (not a screen recording of a speaker).
No obvious clipping on the loudest section.
Under 5:00 and under 15 MB (or plan a split).
Format is MP3, WAV, M4A, or FLAC.

Once the file passes those checks, upload it. If the result still has bleed, the mix may be the limit — not your prep. Our how-to guide covers how to judge output and when to stop tweaking.