If you have the original PCM WAV and an MP3 made from it, use the WAV. If your original is FLAC, decode it to WAV before uploading; this preserves its audio detail. If you only have a usable MP3, upload it directly; converting it to WAV will not restore missing detail.
Start with the recording’s history. An original lossless source avoids an extra lossy encoding step, but a WAV extension alone does not prove you have that original.
Which file should you upload?
| Files you have | Choose | Why |
|---|---|---|
| The original WAV and an MP3 copy made from it | The original WAV | Making the MP3 copy discards some audio detail. |
| A WAV file and a FLAC made directly from it | Use the WAV for upload | FLAC keeps the WAV’s audio detail and usually takes up less space. |
| Only an MP3 | Upload the MP3 as it is | Conversion would not bring back audio detail missing from the MP3. |
| Only a WAV converted from an MP3 | Use that WAV | It has no extra original detail just because it is now a WAV. |
| Several files, but you are unsure | Choose the clearest copy of the version you need | A larger file or .wav extension alone does not prove better sound. |
Understand what conversion can change
MP3 uses lossy compression, which discards or reduces the precision of some audio information. Decoding that MP3 to WAV does not recreate what was discarded.
WAV is a container, commonly used with uncompressed PCM audio. FLAC compresses audio losslessly; its smaller size does not mean it contains less detail than the same decoded PCM source.
Check whether the problem is in the source or the separation
Listen to the original and separated output at similar levels. If distortion or noise is already in the original, changing the extension will not remove it. If recognizable words remain only in the instrumental, or useful notes disappear during separation, judge the output on its own merits.
A lossless source still cannot guarantee a clean split. The mix, overlapping sounds, effects, and separation model also affect what you hear. If words, harmonies, or echoes remain, use the vocal-removal troubleshooting guide to identify the likely cause.
Choose the download for your next step
Input and output formats are separate decisions. A WAV download made from an MP3 input does not turn the original recording into a lossless source.
For more editing, keep a lossless output when the tool offers one. For a sharing or practice copy, choose a format accepted by your destination. Check the actual export options rather than assuming every supported input is also a download format.
Start with the source you already have
Upload an MP3 or WAV to TuneStem, then preview the vocal or instrumental you need before downloading.