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Free AI mastering tools vs Burnish: what free costs you

Updated 2026-09-06

Free mastering tools exist and some of them are decent. This page is not a takedown. It is a list of what to check before you release a song through one.

What most free tools do

Apply a preset chain: an EQ curve, a compressor, a limiter, aimed at a loudness number. Some let you pick a style. The good ones do it with care and the result is louder and brighter than the input.

What they usually skip

• Measurement. A preset does not know your file has a cutoff at 16 kHz and 5 dB of mud at 350 Hz. It applies the same curve to a track that has neither.
• Repair. Loudness first makes AI artifacts louder. The rebuild, the mud cut and the widening have to happen before the limiter.
• True peak. Many free limiters are sample-peak. The file measures clean and clips after upload.
• The report. Without it you cannot tell what changed, so you cannot tell whether it helped.

Where the file goes

Most free tools are browser uploads to a server. Read the terms. Some keep the upload, some train on it, some are free because the upload is the product. A track nobody has heard yet deserves a clear answer to "where does this go." Burnish for iOS never sends it anywhere. On the web, Burnish keeps files only long enough to produce the master and does not train on them.

When paying is cheaper

When the track is going to a distributor, when it is the one that gets pitched, or when you have already spent an evening fighting a free tool's preset. Five dollars for a master that is measured, repaired, printed and true-peak safe is the cheapest part of a release. The analysis and the preview are free either way, so you can see the numbers before you decide.