Mix Analyzer guide
Audio Source Quality Analysis
Tell a degraded MP3 source from a dull mix - and never master from a lossy file by accident.
What source quality analysis really tells you
You cannot master a 16 kHz MP3 - if the data is gone, no plugin brings it back. Producers worry their files are secretly degraded, and here is the reassuring part from our data: the tracks run through Mix Analyzer are almost always genuine full-quality sources, not sneaky MP3s wrapped as WAV. The catch is the opposite one - when the spectrum stops short, it is usually a dull mix, not a damaged file. Those two look similar and need completely different fixes, so the first job is telling them apart.
Lossy detection
Whether the file carries the brick-wall fingerprint of MP3 or AAC encoding.
Spectral cutoff
Where the energy stops - a hard shelf means a codec, a soft roll-off usually means the mix.
Sample rate
The project rate the file was rendered at.
Bit depth
Effective resolution estimated from the noise floor.
Lossy file or just a dull mix?
This is the distinction that matters, because the fixes are opposite. A lossy source has thrown data away for good; a dull mix still has all its data, it just needs EQ and arrangement. The spectrum is how you tell.
How to read it
- A hard, flat brick-wall cutoff at a round frequency means a codec put it there - the file was lossy at some point.
- Rough MP3 guide: 128 kbps cuts near 16 kHz, 192 near 18 kHz, 320 near 20 kHz; AAC cuts higher and softer.
- A gentle roll-off that tapers toward the top is usually just a dull or narrowband mix, not a damaged file.
- A full spectrum is not proof of lossless - upscaled "fake FLAC" can look full and still be degraded.
What we see most often
The good news first: in the tracks we analyze, genuinely lossy source files are rare - most people are working from real lossless masters. The more common issue is a mix that simply lacks top end, which reads as low quality but is completely recoverable.
The takeaway
- Most uploads are real full-quality sources, not hidden MP3s.
- When the top end is missing, suspect the mix before you blame the file.
- A dull mix is an EQ and arrangement fix; a lossy file is a re-export-from-the-original fix.
- If in doubt, find the original render and compare.
The common problems - and how to fix each
Most source-quality damage is avoidable with a couple of habits. The rule of thumb: keep one lossless master and only ever export lossy at the very end.
Problem then fix
- Mastering from an MP3: stop and find the original WAV or AIFF - the artifacts are permanent.
- Transcoding lossy to lossy: never round-trip through MP3 mid-project, because each pass loses more.
- Fake FLAC or upscaled hi-res: check the spectrum for the original cutoff; the container lies, the spectrum does not.
- Low bit depth: record and bounce at 24-bit so the summed noise floor stays inaudible.
- Lossy stems: ask collaborators for WAV stems, not MP3s.
- Streaming rips: use a downloaded reference for A/B only, never as material to mix.
What Mix Analyzer adds
You get the source read before you waste time on it - whether it looks lossy, where the spectrum stops, and whether the limit is the file or the mix.
In every analysis
- A lossy-versus-lossless assessment from the spectral fingerprint.
- The spectral cutoff frequency, so you can see where the energy ends.
- Sample rate and an estimated effective bit depth.
- A plain read on whether the source is worth mastering as is.
Frequently asked questions
Can I master from an MP3?
You can, but you should not. The lossy cutoff and artifacts are permanent and mastering EQ and limiting only amplify them. Always source the original WAV or AIFF.
How do I tell if a file is really lossless?
Open it in a spectrogram viewer and look at the top of the range. A hard, flat cutoff around 16-20 kHz means it was lossy at some point, even if it is now wrapped as WAV or FLAC. A full spectrum to about 22 kHz is a good sign, though not absolute proof.
What bitrate is good enough?
For delivery, 256 kbps AAC or 320 kbps MP3 is transparent to most listeners. For source material you are going to mix or master, no lossy bitrate is good enough - work from lossless.
Does 24-bit or 96 kHz actually matter?
For working - recording and mixing - 24-bit is worth it because it lowers the cumulative noise floor and adds headroom. For listening, 16-bit and 44.1 kHz already exceed normal human hearing.
What is a brick-wall cutoff?
A near-vertical drop where all energy above a frequency disappears, created by a codec low-pass filter. On a spectrogram it looks like a hard ceiling and is the clearest fingerprint of lossy encoding.
Can I restore a lossy file by exporting it to WAV or FLAC?
No. Converting to a lossless container does not bring back discarded data; it just makes a bigger file with the same artifacts. That is exactly what fake FLAC is.
Further reading
- Wikipedia - Lossy compression — How lossy codecs discard data and why artifacts accumulate.
- Wikipedia - MP3 — MP3 encoding, the psychoacoustic model, and its artifacts.
- Wikipedia - Audio bit depth — How bit depth sets the noise floor and dynamic range.
- Wikipedia - Generation loss — Why each lossy re-encode degrades quality further.
- iZotope Learn - Sample rate and bit depth — A plain-language explainer for music work.
Analyze your own mix
Upload a track to compare what you hear against Mix Analyzer's technical measurements and AI-assisted recommendations.
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