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Mixing balances tracks and effects within a song. Mastering optimises the final mix for distribution: level, overall tone, dynamics and consistency. lexpi processes an already-mixed stereo file. It is not a mixing tool.

WAV or AIFF, 24-bit minimum, at 44.1 kHz or 48 kHz. The file must be between 30 seconds and 30 minutes long. Mono and stereo are both accepted.

24-bit preserves the dynamic headroom required by the processing. A 16-bit file has already been reduced and may produce artefacts during mastering.

Check that the file is WAV or AIFF, 24-bit or above, at 44.1 kHz or 48 kHz, between 30 seconds and 30 minutes. Make sure the export is stereo interleaved and that the file is not corrupted. The upload screen tells you the exact reason.

1 credit covers 10 minutes of audio. Any started 10-minute slot is due in full. For example, a 4-minute track costs 1 credit; a 12-minute track costs 2.

Yes. Analysis and the compressed A/B preview are free. You only pay to download the lossless files (24-bit WAV, 16-bit WAV, 320 kbps MP3).

Credits are valid for 12 months from the purchase date. The expiration date is shown on your Tokens page. You will receive an email notification before they expire.

Credits cannot currently be extended. Please use them within 12 months of purchase.

They come from the same processing. The preview is encoded as MP3, which may slightly change perception. The final WAV is the lossless, uncompressed result.

Clipping is most often already present in the mix. Common causes: limiter too aggressive on the master bus, gain too high. Solution: bring the master fader down a few dB, remove the limiter from the master bus, and re-export.

Yes. For an optimal premaster, remove the limiter (and ideally the compressor) from the master bus. Aim for headroom: a signal peaking between -6 and -3 dBTP. Mastering takes care of the rest.

No. Mastering optimises a correct mix for distribution. An unbalanced mix (too much bass, buried vocals, mis-panned instruments) will stay unbalanced. Fix your mix first.

It means your file's dynamics are very limited (Dynamic Range < 8 dB, LUFS > -14). Processing will have little headroom and may be more aggressive than intended. Export a premaster without a limiter for a better result.

Export a clean premaster: no clipping, headroom (-6 to -3 dBTP), no unnecessary dither, no destructive normalisation, no exotic sample-rate conversion. See the premaster guide on the upload page.

Yes. The 16-bit master is exported with triangular dither (TPDF) applied to the 24→16-bit conversion. You can use it as-is for CD burning or distribution.

If the master sounds crushed, your mix is probably already very compressed. Re-export a mix with more dynamics (remove the limiter from the master bus). Mastering handles the final level.

Mastering respects the tonal balance of your mix. If the result lacks bass or highs, the issue most likely comes from the mix. Check your mix on several listening systems before re-exporting.

No, never. Your files are processed only to produce your master. They are neither shared nor used for training. See our Ethics page for details.

Previews are kept for 7 days. Paid masters remain available while your account is active. Uploaded and abandoned files are purged within 24 hours. All retention periods are detailed in our privacy policy.

Yes. Open your Account page to export your data (JSON) or request account deletion. Deletion erases all your audio files (S3), your database records and your Clerk account. A confirmation email is sent.

Yes. From your Account page, you can export your profile, transaction history, consents and files as JSON.

Common causes: 3D Secure authentication failed, bank limit reached, card not compatible with online payments. Try again or use another payment method.

Check your transaction history on the Tokens page. If a duplicate is confirmed, contact support@updates.lexpi.ai with the transaction reference.

Yes. Re-downloading a paid master is unlimited and free. Find your masters in the Library.

In discovery mode (0 credit), you can analyse and listen to one file at a time. This guarantees server capacity and prevents abuse. Buy credits to process several files in parallel.

Yes, track by track. Each file is processed independently. With enough credits, you can have up to 10 files active in parallel.

A file is rejected when it doesn't meet the technical criteria: format (WAV/AIFF only), resolution (24-bit minimum), sample rate (44.1/48 kHz), duration (30s-30min), or when it is detected as silent or severely clipped. The upload screen explains the reason and how to fix it.

Check that your source file is not corrupted and that the export is complete (no cut at the end of the song). Re-upload the file.

In case of a verified billing error: yes. In case of aesthetic disappointment: no. Mastering is an automated technical process. The result depends on the mix provided. See our Terms (art. 6 and 7) for the full policy.

You keep full rights to your music. lexpi claims no right over uploaded files or generated masters. See our Terms (art. 8).