Beat File Formats: WAV, MP3, Stems and MIDI
Why the file you receive decides what you can do
When you license a beat, the audio file is not a souvenir; it is the raw material of your release. The format determines how much editing headroom you have, how the track survives mastering, and sometimes what a licence actually grants. Two families matter: uncompressed (or losslessly compressed) audio such as WAV, and lossy compressed audio such as MP3. Uncompressed files store every sample the producer exported; lossy files discard data to shrink the file, and that discarded data cannot be recovered by re-encoding later.
Producers and marketplaces such as BeatStars and Airbit commonly attach a file bundle to a licence tier: a tagged MP3 for auditioning, an untagged WAV for release, and sometimes tracked-out stems. "The master" in a beat licence usually means the producer's final stereo mixdown of the instrumental — the reference recording you are permitted to use. It is not automatically the same as a Mastering-ready deliverable for your full song, because your vocal still has to be mixed into it. Check the licence text for the exact words used for the delivered file, the permitted distribution limits, and whether stems are included or sold separately.
Specification table: sizes and trade-offs
The size figures below assume stereo audio, a duration of exactly 3 minutes (180 seconds), and no container padding or metadata overhead. PCM size = seconds × sample rate × channels × bytes per sample. Compressed size = seconds × bitrate ÷ 8.
| Format | Compression | Typical spec | Approx. size of a 3-minute stereo instrumental | When it is the right choice |
|---|---|---|---|---|
| WAV 16-bit/44.1 kHz PCM | None (lossless) | 44,100 Hz, 16-bit, stereo | ~31.8 MB (180 × 44,100 × 2 × 2 bytes) | Standard release master; CD-resolution delivery |
| WAV 24-bit/48 kHz | None (lossless) | 48,000 Hz, 24-bit, stereo | ~51.8 MB (180 × 48,000 × 2 × 3 bytes) | Mixing and video work; extra dynamic headroom |
| MP3 320 kbps CBR | Lossy | 320 kbps constant bitrate, 44.1 kHz | ~7.2 MB (180 × 320,000 ÷ 8 bytes) | Reference listening, DJ promos, quick sharing |
| MP3 128 kbps | Lossy | 128 kbps, 44.1 kHz | ~2.9 MB (180 × 128,000 ÷ 8 bytes) | Previews and low-bandwidth streaming only |
| AAC 256 kbps | Lossy | 256 kbps, 44.1 kHz | ~5.8 MB (180 × 256,000 ÷ 8 bytes) | Consumer streaming and mobile playback |
| FLAC | Lossless compression | 16- or 24-bit, 44.1–96 kHz | ~50–70% of the equivalent WAV size (roughly 16–22 MB for a 3-minute 16-bit/44.1 kHz file) | Archiving masters without losing samples |
| MIDI | None (event data) | Note, velocity, controller messages; no audio | Kilobytes — near-zero MB | Re-arranging parts, changing instruments, tempo maps |
MIDI is not audio. It records performance instructions — which note, how hard, when — so it can follow a new Tempo or drive a different instrument. A MIDI file of a beat is useful only if you also hold the sounds and the right to use the composition; it is not a substitute for the instrumental recording.
Stems and multitrack deliveries
A stereo file gives you one lane: vocal plus instrumental. Stems split the instrumental into groups so an engineer can balance your voice against the beat. A 2-stem delivery is usually instrumental plus a cappella, or drums plus everything else. A 6-stem delivery typically separates drums, bass, keys, lead melody, pads or strings, and effects or percussion. Full multitrack means every recorded element on its own track — kick, snare, hats, 808, each synth layer — which is the most flexible and the most work to manage.
For mixing a vocal, the practical target is at least four to six stems: drums (kick, snare, hats combined), bass, harmonic instruments (keys, guitars, pads), and lead melodic elements. That lets you duck the lead during verses, keep the kick clear of your low vocal, and ride the music under a chorus without touching the drums. Full multitrack is worth requesting when the arrangement needs surgery — cutting a section, replacing a synth, or sidechaining the bass to your vocal bus.
Session files exported as 32-bit float preserve values above 0 dBFS and below the noise floor, so gain changes during mixing do not clip or lose detail. If a producer offers a 32-bit float session alongside stems, take it; you can always render down to 16-bit or 24-bit WAV at the end. See the Mastering overview for how the final loudness stage fits after your mix, and note that streaming platforms apply their own level targets — Spotify loudness normalization describes how playback level is adjusted on that service.
How to store and back up your licence package
Keep every beat you license in one project folder so the paperwork and audio never separate. A workable layout, in order:
/license— the licence PDF or text, with the tier name, permitted uses, and any distribution cap./audio— the delivered stereo master(s): WAV first, MP3 copy for reference./stems— tracked-out files, named by instrument, plus any 32-bit float session./contract-pdf— the signed agreement, producer contact details, and any split sheet./receipt— proof of payment, order number, and date of purchase.
Apply the 3-2-1 rule concretely: keep three copies of the folder, on two different storage types (for example an internal drive and an external SSD), with one copy off-site — cloud storage or a drive kept at another address. Verify the backup by opening the WAV and the licence PDF from the off-site copy, not just by checking that a sync icon is green. A licence you cannot produce on request is difficult to rely on if a distributor or platform asks for proof of rights. The International Standard Recording Code (ISRC) is the identifier a distributor assigns to the finished recording, so keep it with the same folder once your song is registered; the glossary explains related terms, and release-workflow.html walks through the delivery sequence from mix to store.
FAQ
Should I re-download the beat later?
Only if the seller updates the file or you lost your copy. Re-downloading does not change the licence terms; the grant is tied to your purchase, not to how many times you fetch the file. Store the original download and its receipt so you never depend on a marketplace account staying active.
What if the seller only offers MP3?
You can still release, but you are working from a lossy source. Ask whether an untagged WAV or stems exist at a higher tier, and check the licence for the permitted file description. If MP3 320 kbps is all that is available, keep it as a reference and request the lossless master before mixing, since repeated encoding degrades the audio.
Do stems cost extra?
Often they are a separate tier or an add-on, because tracked-out files take more time to prepare. Read the tier list before paying and confirm exactly which files are included: stereo only, 2-stem, 6-stem, or full multitrack.
Can I use a MIDI file instead of the audio?
MIDI carries no audio, so it cannot replace the instrumental recording. It is useful for changing Tempo, swapping instruments, or rebuilding an arrangement — but you still need the recording and the rights that cover it.
What sample rate should I send to my mixing engineer?
Send the highest-quality files you received: 24-bit/48 kHz WAV or the 32-bit float session if available. Downsample only at the final render, and keep the original folder untouched. The index.html page collects the site's starting points on choosing and licensing instrumentals.
How do I prove I licensed the beat?
Keep the licence PDF, the receipt, and the producer's contact details together. If a distributor or platform queries the release, those documents plus the delivered files are your evidence. Back them up off-site so a single drive failure cannot erase your rights record.